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The nutritional status and physical work performance of children of migrant agricultural workers in Southern.. 1981

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THE NUTRITIONAL STATUS AND PHYSICAL WORK PERFORMANCE OF CHILDREN OF MIGRANT AGRICULTURAL WORKERS IN SOUTHERN BRAZIL by CHARLOTTE WADDELL B . S c , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1978 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES D i v i s i o n o f Human N u t r i t i o n S choo l o f Home Economics ' We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o the r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA A p r i l 1981 © CHARLOTTE WADDELL, I 9 8 I I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an advanced degree a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e head o f my department o r by h i s o r h e r r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f The U n i v e r s i t y o f B r i t i s h C o l u m b i a 2075 Wesbrook P l a c e Vancouver, Canada V6T 1W5 i i ABSTRACT A s t u d y was c o n d u c t e d t o i n v e s t i g a t e and compare the n u t r i t i o n a l s t a t u s and p h y s i c a l work performance o f c h i l d r e n o f B r a z i l i a n m i g r a n t a g r i c u l t u r a l w o r k e r s w i t h B r a z i l i a n c h i l d r e n from w e l 1 - t o - d o backgrounds. The r e l a t i o n s h i p between n u t r i t i o n a l s t a t u s and p h y s i c a l work performance was a l s o i n v e s t i g a t e d . D i e t a r y a n a l y s i s was conducted u s i n g the 24-hour d i e t r e c a l l method. E v i d e n c e was found t h a t i n t a k e s o f e n e r g y , c a l c i u m , t h i a m i n , r i b o f l a v i n , n i a c i n , and v i t a m i n C may have been i n a d e q u a t e among m i g r a n t w o r k e r c h i l d r e n . T h e i r d i e t was g e n e r a l l y monotonous and c o n s i s t e d m a i n l y o f r i c e , beans, and c o f f e e w i t h s u g a r . D i e t s o f w e l l - t o - d o c h i l d r e n were c o n s i d e r a b l y more v a r i e d w i t h good r e p r e s e n t a t i o n from a l l major food groups. A n t h r o p o m e t r i c assessment i n d i c a t e d t h a t m i g r a n t worker c h i l d r e n had v a l u e s f o r w e i g h t and t r i c e p s s k i n f o l d t h i c k n e s s t h a t were low compared to American s t a n d a r d s . V a l u e s f o r h e i g h t , arm c i r c u m f e r e n c e , and arm muscle c i r c u m f e r e n c e were average compared t o American s t a n d a r d s . W e l l - to-do c h i l d r e n exceeded American s t a n d a r d s f o r a l l a n t h r o p o m e t r i c p a r a - meters measured. B i o c h e m i c a l i n v e s t i g a t i o n s o f p r o t e i n and i r o n s t a t u s were a l s o con- d u c t e d . Serum t o t a l p r o t e i n and a l b u m i n l e v e l s were normal i n most s u b j e c t s i n both groups. However, many m i g r a n t worker, c h i 1 d r e n had low v a l u e s f o r h e m a t o c r i t , serum i r o n , and t r a n s f e r r i n s a t u r a t i o n . Most w e l l - t o - d o c h i l d r e n had normal v a l u e s f o r t h e s e p a r a m e t e r s . Hemoglobin l e v e l s were adequate i n most s u b j e c t s . i i i Physical work performance was found to be impaired in migrant worker c h i l d r e n . Exercise heart rates and post -exerc i se blood l a c t i c ac id leve ls in response to a standardized bicycle-ergometer work test were s i g n i f i - cant ly higher in migrant worker compared to wel1-to-do c h i l d r e n . In add i - t i o n , a s i g n i f i c a n t c o r r e l a t i o n was found between anthropometric i n d i - cators o f n u t r i t i o n a l status and parameters of physical work performance. F i n a l l y , socio-economic and eco log ica l assessment indicated that the l i v i n g condit ions of migrant worker ch i ld ren were impoverished and un- san i ta ry . This probably aggravated health problems such as in fect ions that were found to occur among these c h i l d r e n . Wel l - to-do ch i ld ren did not share these cond i t ions . i v TABLE OF CONTENTS Page ABSTRACT i i LIST OF TABLES v i LIST OF FIGURES v i i ACKNOWLEDGEMENTS v i i i CHAPTER I INTRODUCTION 1 II REVIEW OF THE LITERATURE 6 1. S o c i o - e c o n o m i c F a c t o r s i n M a l n u t r i t i o n 6 2. Assessment o f N u t r i t i o n a l S t a t u s 7 3. Assessment o f P h y s i c a l Work Performance 15 k. A s s o c i a t i o n Between N u t r i t i o n a l S t a t u s and P h y s i c a l Work Performance 18 5- N u t r i t i o n i n B r a z i l 25 a) B r a z i l i a n S o c i o - e c o n o m i c S i t u a t i o n 25 b) N u t r i t i o n a l S t a t u s o f B r a z i l i a n P e o p l e 29 i ) N a t i o n a l S t u d i e s •. 29 i i ) S t u d i e s i n R i b e i r a o P r e t o , Sao P a u l o 3k I I I METHODS AND MATERIALS 38 1. P o p u l a t i o n and Sample 38 2. E x p e r i m e n t a l P r o c e d u r e 39 3. Assessment o f N u t r i t i o n a l S t a t u s kO a) S o c i o - e c o n o m i c F a c t o r s hO b) D i e t a r y A n a l y s i s kO c) A n t h r o p o m e t r i c D e t e r m i n a t i o n s 43 d) B i o c h e m i c a l T e s t s . kk k. Assessment o f P h y s i c a l Work Performance 51 5- S t a t i s t i c a l A n a l y s i s 53 IV RESULTS 5k 1. Assessment o f N u t r i t i o n a l S t a t u s 5k a) S o c i o - e c o n o m i c F a c t o r s 5k b) D i e t a r y A n a l y s i s 59 c) A n t h r o p o m e t r i c D e t e r m i n a t i o n s . 69 d) B i o c h e m i c a l T e s t s Ik 2. Assessment o f P h y s i c a l Work Performance 78 3. A s s o c i a t i o n Between N u t r i t i o n a l S t a t u s and P h y s i c a l Work Performance 78 V DISCUSSION 8k 1. S o c i o - e c o n o m i c C o n s i d e r a t i o n s 8k V 2. Assessment of Nut r i t i ona l Status 86 a) Dietary Analys is 86 b) Anthropometric Determinations 91 c) Biochemical Tests Sk 3- Assessment of Physical Work Performance 97 k. Assoc iat ion Between Nut r i t i ona l Status and Physical Work Performance 99 VI SUMMARY AND CONCLUSIONS 102 BIBLIOGRAPHY 107 v i LIST OF TABLES Table Page 11-1 Typical d iet of b o i a - f r i a migrant workers. . 37 IV—1 Comparison of ind icators of health status in subjects from b o i a - f r i a and we l l - to -do fami l ie s 60 IV-2 Comparison of da i l y nutr ient intake of subjects from b o i a - f r i a and we l l - to -do fami l ie s 61 IV—3 Dai ly nutr ient intake of subjects from b o i a - f r i a and we l l - to -do fami l ie s in comparison with WHO/FAO recommended da i l y intakes. . . 6 2 IV-4 Number of subjects with da i l y nutr ient intake less than 2/3 of recommended da i l y intake 6 4 1V-5 Contr ibut ion of food groups to nutr ient intake 6 4 IV-6 Sample da i l y menus taken from d ie t r eca l l s co l l e c ted from b o i a - f r i a subjects 67 IV-7 Sample da i l y menus taken from d ie t r eca l l s co l l e c ted from we l l - to -do subjects 68 IV-8 Comparison of physical growth and development of subjects from b o i a - f r i a and we l l - to -do fami l ie s 70 IV-9 Comparison of blood biochemistry in subjects from b o i a - f r i a and we l l - to -do fami l ie s 79 IV-10 Blood biochemistry in subjects from bo i a - f r i a and we l l - to -do fami l ie s in comparison with normal values . . . 76 IV-11 Number of subjects having biochemical parameters below normal value 77 IV-12 Comparison of change in heart rate in subjects from b o i a - f r i a and we l l - to -do fami l ie s 8 0 1V — 13 Comparison of blood l a c t i c ac id levels before and a f t e r exerc i se in subjects from b o i a - f r i a and we l l - to -do fami l ie s 81 IV-14 Corre la t ions between selected pairs of var iab les 83 vi i LIST OF FIGURES Figure Page 11-1 Stages of ma lnutr i t ion 8 I I-2 Map of Brazi 1 . 27 I I 1-1 Questionnaire used in 24-hour d iet r eca l l interviews k2 IV-1 Typical house in V i l a Recreio 55 IV-2 Typica l s t reet in V i l a Recreio 55 IV—3 Typical corner store in V i l a Recreio 57 IV-4 Goods ava i l ab le in typ ica l store in V i l a Recreio 57 IV-5 Typica l house in Jardim Recreio 58 IV-6 Typica l house in Jardim Recreio 58 IV-7 Weight of subjects from b o i a - f r i a and we l l - to -do fami l ie s in comparison with standards 71 IV-8 Height of subjects from b o i a - f r i a and we l l - to -do f ami l i e s in comparison with standards 72 IV-9 Sk info ld th ickness , arm circumference, and arm muscle circumference of subjects from b o i a - f r i a and we l l - to -do fami l ie s in comparison with standards 73 IV-10 Change in heart rate with.t ime in b o i a - f r i a and we l l - to -do subjects 79 v i i i ACKNOWLEDGEMENTS To my r e s e a r c h d i r e c t o r , Dr. l.D. D e s a i , I would l i k e t o e x t e n d my s i n c e r e thanks f o r f a c i l i t a t i n g t h i s p r o j e c t and f o r a s s i s t i n g me t h r o u g h - out, i t . I a l s o w i s h t o e x p r e s s my a p p r e c i a t i o n t o my o t h e r r e s e a r c h a d v i s o r s , Dr. M e l v i n Lee and Dr. B l a n c a M u r a t o r i o , f o r t h e i r g u i d a n c e and encouragement i n the p r e p a r a t i o n o f t h i s t h e s i s . In a d d i t i o n , I w i s h t o thank Lewis James and V i r g i n i a Green f o r t h e i r most v a l u a b l e h e l p i n d e v e l o p i n g computer programs t o a n a l y s e the d a t a f o r t h i s p r o j e c t . I would l i k e t o o f f e r a s p e c i a l thanks t o the many B r a z i l i a n p e o p l e w i t h o u t whom t h i s p r o j e c t would not have been p o s s i b l e : Dr. J.E. Dutra de O l i v e i r a , D i r e c t o r o f the F a c u l t y o f M e d i c i n e , U n i v e r s i t y o f Sao P a u l o , R i b e i r a o P r e t o ; E. Duarte and M.L. Robazzi from the School o f N u r s i n g , U n i v e r s i t y o f Sao P a u l o , R i b e i r a o P r e t o ; Dr. L.S. C e v a l l o s Romero and Dr. F.L. V i c h i from t h e C a r d i o l o g y U n i t , H o s p i t a l das C l i n i c a s , U n i v e r s i t y o f Sao P a u l o , R i b e i r a o P r e t o ; C. B o s e r e t , D i r e c t o r , V i t a Pax C o l e g i o ; V.L. F a r i a Fernandes, D i r e c t o r , C e n t r o E d u c a t i o n a l SESI No. 3^6; and M. l o z z i , D i r e c t o r , O r g a n i z a c a o V i d a Nova. A s p e c i a l thanks i s a l s o o f f e r e d t o M. Desai and t o the s t a f f a t both the H o s p i t a l das C l i n i c a s and t h e Department o f C l i n i c a l M e d i c i n e a t t he U n i v e r s i t y o f Sao P a u l o i n R i b e i r a o P r e t o f o r t h e i r c h e e r f u l a s s i s t a n c e i n c o n d u c t i n g t h i s r e s e a r c h . To t h e B r a z i l i a n c h i l d r e n who p a r t i c i p a t e d i n t h i s s t u d y and from whom I l e a r n e d so much: o b r i g a d a , from t h e h e a r t ! F i n a l l y , I w i s h t o acknowledge the f r i e n d s , both Canadian and B r a z i l i a n , and t h e f a m i l y members who gave me g r e a t s u p p o r t i n d o i n g t h i s t h e s i s . In p a r t i c u l a r , I e x t e n d a s p e c i a l thanks to. David J i l e s , ix my parents, and George Hermanson. Their warmth, pat ience, and informed feedback enabled me to see th is work to completion. 1 CHAPTER I INTRODUCTION "The oppressed, who have been shaped by the death- a f f i rming c l imate of oppress ion, must f ind through the i r s trugg le the way to l i f e - a f f i r m i n g humanization, which does not l i e s i mply in having more to eat (although i t does involve having more to eat and cannot f a i l to i n - clude th is aspect ) . The oppressed have been destroyed p rec i se l y because the i r s i t ua t i on has reduced them to things. In order to regain the i r humanity they must cease to be things and f i gh t as men." (Paulo F r e i r e , 1970) Braz i l has been heralded by many to be an example of a development mirac le among th i rd world nat ions. A country t r a d i t i o n a l l y bound to an agr icu l tura1 -export economy, Braz i l in the ear ly 19701s managed to increase i t s a g r i c u l t u r a l and i ndus t r i a l output by an astounding 10% annual ly, a growth rate exceeded by few developed countr ies . Yet c lo ser scrut iny of this development mirac le has y ie lded increas ing evidence that national economic growth has occurred at the expense of the vast majority of B r a z i l i a n people. The a g r i c u l t u r a l and indus t r i a l labourers on whom pro- docution depended have rea l i zed very l i t t l e of the burgeoning B r a z i l i a n wealth. For most workers and peasants, poverty, ma lnut r i t i on , i l l i t e r a c y , inadequate medical care, inadequate housing, and lack of p a r t i c i p a t i o n in p o l i t i c a l processes have continued to be a way of l i f e , as in the past. These are the oppressed about whom Fre i re (1970) speaks. These are a l so the subjects of this study. B raz i l today is the world 's seventh largest country in terms of populat ion, and f i f t h in terms of s i z e , i t s economy is s t i l l large ly based on the export of a g r i c u l t u r a l products such as co f fee , soybeans, 2 and s u g a r , however massive e x p a n s i o n o f the i n d u s t r i a l s e c t o r has o c c u r r e d r e c e n t l y i n the s o u t h o f B r a z i l , e s p e c i a l l y i n the s t a t e o f Sao P a u l o . The n o r t h o f B r a z i l i s v e r y poor i n c o m p arison t o the s o u t h : c l i m a t e i s d r y and i n h o s p i t a b l e t o a g r i c u l t u r e , e x c e p t on the c o a s t , and i n d u s t r i e s o t h e r than s u b s i s t e n c e f i s h i n g and f a r m i n g have not been d e v e l o p e d . Extreme p o v e r t y , c r o p f a i l u r e s , and c h r o n i c unemployment a r e major m o t i v a t i n g f a c t o r s f o r B r a z i l i a n s from the n o r t h t o m i g r a t e s o u t h , a t t r a c t e d t o the hope o f j o b s i n the c i t i e s o r on the f e r t i l e c o f f e e o r sugar p l a n t a t i o n s . U n f o r t u n a t e l y , urban c e n t e r s i n the s o u t h have r a r e l y been e q u i p p e d t o h a n d l e t h e i n f l u x o f m i g r a n t s . Most m i g r a n t s must l i v e i n h a s t i l y c o n s t r u c t e d f a v e l a s o r shanty-towns on the edges o f c i t i e s and towns, and most l a c k a c c e s s t o even the most b a s i c f a c i l i t i e s f o r m e d i c a l c a r e o r e d u c a t i o n . The e x i s t e n c e o f m a l n u t r i t i o n i n B r a z i l has been documented by many r e s e a r c h e r s . I t o c c u r s among the peasant f a r m i n g and f i s h i n g f a m i l i e s o f the n o r t h and among t h o s e who m i g r a t e s o u t h and d w e l l i n urban fave1 a s . S p e c i f i c problems t h a t have been i d e n t i f i e d i n c l u d e i n a d e q u a t e v i t a m i n A, p r o t e i n , e n e r g y , t h i a m i n , r i b o f l a v i n , v i t a m i n C, i r o n , and c a l c i u m n u t r i t u r e , a l t h o u g h m a l n u t r i t i o n w i t h r e s p e c t t o t h e s e n u t r i e n t s has o f t e n been i d e n t i f i e d as s u b - a c u t e o r e a r l y - s t a g e ( I n t e r d e p a r t m e n t a l Committee on N u t r i t i o n f o r N a t i o n a l Defense - ICNND, 1965; P a t r i c k and Simoes, 1971; Roncada, 1972; A l v e s , 1977; Jansen e_t aj_. , 1977; M a r t i n s et^ aj_. , 1976; and Desai et^ a_l_. , 1980) . V i t a m i n A and s u b - a c u t e p r o t e i n - energy m a l n u t r i t i o n have been i d e n t i f i e d as problems p a r t i c u l a r l y a f f e c t - i n g B r a z i l i a n c h i l d r e n (Waterlow and V e r g a r a , 1956; ICCND, 1965; G u i t t i , 1974; S i g u l e m et_ a]_., 1976; Simmons, 1976; Roncada et^ aj_. , 1978; and O l s o n , 1979 ) . 3 I n su f f i c ient a t tent ion has been paid in the past to amel iorat ing these nu t r i t i ona l problems of the B r a z i l i a n poor, perhaps because much of the i r ma lnutr i t ion is not acute or late in stage. Ma lnutr i t ion in i t s ear ly stages is o f ten undramatic and unobtrusive even though i t can cause da i l y eros ion of health in epidemic proportions among people in develop- ing countr ies such as B raz i l (Berg, 1973) - One poss ib le side e f f e c t of malnutr i t ion in i t s e a r l i e r stages which has not been c l e a r l y character - i zed , e s p e c i a l l y among c h i l d r e n , may be the impairment of physical work performance (Spurr et_ aj_. , 1978 ) . The a s soc ia t ion between nu t r i t i ona l status and physical work per fo r - mance is of in terest for several reasons. F i r s t , the loss of health and we l l -be ing , inc luding loss of physical f i t n e s s , which may be experienced by the ind iv idua l who is undernourished is of unequivocal importance and needs to be we 11-documented so that preventive measures can be e f f e c t i v e l y conceived. Second, undernourished ind iv idua l s may experience economic losses i f income is d i r e c t l y dependent on work output, as is the case for many a g r i c u l t u r a l labourers in countr ies such as B raz i l (Food and Agr i cu l ture Organization-FAO, 1 962 ) . T h i r d , there may be economic rami f i cat ions for developing countr ies such as B r a z i l , which depend heavi ly on manual labour for product ion, i f the physical work performance of many ind iv idua l s is adversely a f fec ted by ma lnut r i t i on . It has been suggested that inadequate d ie t s can resu l t in net losses for national economies by causing decreased work output, shorter working l i f e span, and increased costs for medical care (FAO, 1962 and Berg, 1973)• Indeed, Correa and Cummins (1970) estimated that increased c a l o r i c consumption alone could account for 5% of the growth in national product in nine Lat in American countr ies studied between 4 1950 and 1962. Economic arguments such as these may sway government planners to recognize and address malnutr i t ion where humanistic arguments have f a i l e d (Berg, 1973)• Few studies in the past have focussed on the poss ib le assoc ia t ion between undernutr i t ion and impairment of physical work performance in B raz i l i an populat ions. A l so, while researchers of other populations have examined and found a re l a t i onsh ip between nu t r i t i ona l status and physical work performance in adu l t s , few studies have examined th is re l a t ionsh ip in c h i l d r e n . C o n f l i c t i n g resu l t s have been obtained from studies that have been done in ch i l d ren (Areskog e_t aj_. , 1969; Spurr et_ aj_. , 1978; Satyanarayana e_t a_l_. , 1979; Ferro-Luzzi et_ aj_. , 1979; and Desai et_ aj_., 1981). The re l a t i onsh ip between n u t r i t i o n a l status,and.physreal work per fo r - mance in ch i ld ren is of in terest in countr ies like. Braz i l because ch i ld ren leave school at an ear ly age to begin various kinds of manual labour. Any impairment of the i r phys ica l work performance that could resu l t from undernutr i t ion w i l l adversely a f f ec t both t h e i r sense of wel l -be ing and the i r a b i l i t y to earn a l i v i n g , as is the case with adul t s . Undernutr i t ion may have an even greater impact on ch i ld ren than adults because of add i - t iona l n u t r i t i o n a l requirements for growth. Hence, the present study was designed to obtain information on the nu t r i t i ona l status and physical work performance of ch i ldren of B r a z i l i a n migrant a g r i c u l t u r a l workers res id ing in urban fave las . Chi ldren from higher socio-economic groups were se lected to serve as a control group. The primary object ives of this study were twofold: to determine whether n u t r i t i o n a l status and physical work performance of ch i ld ren of migrant worker s ' d i f fe red s i g n i f i c a n t l y from nu t r i t i ona l status and phys i - cal work performance of ch i ld ren from h i gherr> soc i o-economi c groups; 5 and to ascer ta in whether physical work performance was re lated to n u t r i - t ional status in these 2 groups of c h i l d r e n . This study was conducted during 1979 in the c i t y of Ribeirao Preto, which is located in the i n t e r i o r of the state of Sao Paulo in southern B r a z i l , and which has a population of approximately 300,000 people. Many migrant workers are a t t rac ted to Ribeirao Preto because jobs are a v a i l - able on nearby sugar cane and coffee p lantat ions . Subjects for th i s study were e i the r ch i ld ren of migrant workers res id ing in favelas on the periphery of Ribeirao Preto, or ch i l d ren of we l l - to -do B r a z i l i a n profess iona l s or businesspeople res id ing in a f f l uent areas of Ribeirao Preto. Nut r i t i ona l status was evaluated using the fo l lowing c r i t e r i a : socio-economic cons iderat ions ; d ie tary assessment, using the 24-hour recal1 method; anthropometric assessment, inc luding the measurement of weight, height,.mid-upper-arm circumference, and t r i ceps sk in fo ld th ickness; and biochemical assessment, inc luding the determination of serum prote in and albumin, and percentage of t r a n s f e r r i n sa tura t ion . Physical work performance was assessed by measuring changes in heart rate and blood l a c t i c ac id leve l s in response to a bicycle-ergometer work tes t . A tota l of 94 subjects between the ages of 11 and 14 were s tud ied. In keeping with the thoughts of Paulo Fre i re (1970) expressed at the beginning of th i s in t roduct ion , i t was not expected that th i s study would address the problems of B r a z i l i a n migrant workers in the i r e n t i r e t y . Rather, i t was merely hoped that the resu l t s of th i s study, by document- ing some of the rami f i cat ions of ma lnutr i t ion in migrant workers' ch i ld ren could serve as a basis for informed act ion to ameliorate nu t r i t i ona l and other problems among B r a z i l i a n migrant workers and the i r f am i l i e s . 6 CHAPTER I I REVIEW OF THE LITERATURE 1 . Socio-economic Factors in Ma lnutr i t ion Human malnutr i t ion is widely acknowledged to be a socio-economic and eco log ica l problem the et io logy of which is complex and m u l t i - f a c t o r i a l . Probably no other factor has greater impact on nu t r i t i ona l status than income (Mel lor, 1973 ) , and numerous studies have documented highly s i g n i - f i c an t d i f fe rences in food consumption across the income spectrum (Call and Levinson, 1973) - Another factor that a f fec t s nu t r i t i ona l status is food a v a i l a b i l i t y , which is inf luenced in turn by c l imate , s o i l , i r r i g a - t i o n , t ransport , storage, and population growth (Berg, 1 973 ) . Lack of knowledge about n u t r i t i o n a l needs is another fac tor which can often cause ma lnutr i t ion even in the midst of wealth (Devadas, 1970). It has been wel1-documented that b a c t e r i a l , v i r a l , or p a r a s i t i c in fect ions can exert s ynerg i s t i c e f f ec t s on the development of ma lnutr i t ion ( J e l l i f f e , 1966). Infections are themselves exacerbated by lack of medical and educational se rv i ce s , and by poor san i tary condit ions (Sa i , 1976). F i n a l l y , cu l tu ra l habits are powerful soc ia l factors that inf luence what people eat . Foods may have re l i g i ou s s i g n i f i c a n c e , may express soc ia l s ta tus , may be d i s t r i bu ted unequally within f a m i l i e s , or may be rejected due to unfami 1 i a r i t y (Devadas, 1970). In summary then, factors which can inf luence nu t r i t i ona l status i n - clude the fo l l owing : income l e v e l ; food a v a i l a b i l i t y ; knowledge of n u t r i - t iona l needs; presence^of i n fec t i on s ; level of medical and educational se rv i ce s ; and cu l tu ra l hab i t s . Because many factors inf luence 7 malnut r i t i on , any attempt to assess nu t r i t i ona l status or to ameliorate ma lnutr i t ion in the community must take a mu l t i - f aceted approach (Sa i , 1976) . Anyone attempting to understand or ameliorate malnutr i t ion must a l so be w i l l i n g to grapple with the underlying causes of poverty, food s c a r c i t y , and lack of medical and educational serv ices which contr ibute to malnutr i t ion in much of the world (McLaren, 1978 ) . Malnutr i t ion has been said to be the consequence of a malfunctioning soc iety (Cravioto and L i c a r d i e , 1 973 ) . Yet the acknowledgement may be long overdue that ce r t a in sectors in soc iety gain from exp lo i t i n g the world 's poor. It has been well documented recent ly that the interests and a c t i v i t i e s of mult inat ional food and agribusiness corporat ions, major governments, and th i r d world e l i t e s play a ro le in perpetuating poverty and food s ca rc i t y in the world (Frank, 1969; George, 1976; and Lappe and Col 1i ns , 1977 ) . These exploi tat i ve interests and.act i vi t ies cons t i - tute the underlying causes of poverty and food s ca rc i t y which McLaren (1978) has suggested should be examined more r i gorous ly . 2. Assessment of Nut r i t i ona l Status The development of ma lnutr i t ion proceeds through several stages commenc- ing with inadequate d i e t . This is followed by deplet ion of body s tores , phys io log ica l and biochemical changes, i l l n e s s , and f i n a l l y death. As Behar (1976) pointed out, d i f f e r e n t methods of assessment must be used to evaluate d i f f e r e n t stages of ma lnut r i t i on . This is i l l u s t r a t e d in Figure I 1-1. An important note is that in the interests of prevent ion, i t is always preferab le to assess malnutr i t ion in i t s e a r l i e s t stages. The e a r l i e s t stage of ma lnu t r i t i on , an inadequate d i e t , can be detected using e c o l o g i c a l , socio-economic, d ie ta ry , and food balance sur- INADEQUATE DEPLETION PHYSIOLOGICAL ILLNESS DIET OF AND AND BODY BIOCHEMICAL PERMANENT RESERVES CHANGES BODY DAMAGE eco log ica l studies • soc i o-economi c b iochemi ca1 studies • biochemical studies anthropometry c l i n i cal exam- . inat ion s tud ies d ietary surveys food balance sheets morbidity data DEATH morbidity data morta1i ty data FIGURE 11-1 Stages of ma lnut r i t ion ' a Modif ied from Behar, 1976. 9 veys. The second stage of ma lnu t r i t i on , deplet ion of body nutr ient s tores , can be detected using biochemical tests of body t i s sues . The ensuing phys io log ica l and biochemical changes that fo l low deplet ion of body nutr ient stores can be assessed using biochemical and c l i n i c a l s tud ies . Advanced ma lnut r i t i on which manifests i t s e l f in i l l n e s s and permanent body damage can be assessed using c l i n i c a l examinations alone. Ma lnut r i - t i on which has resu l ted in death can be studied by examining morbidity and morta1ity data. Because there are inherent l im i t a t i ons in methodologies for assessment of ma lnutr i t ion at a l l stages, most comprehensive n u t r i t i o n surveys examine as many indices of n u t r i t i o n a l status as poss ib le ( J e l l i f f e , 1966) . This review w i l l cover aspects of d i e ta ry , anthropometric, and biochemical assessment of n u t r i t i o n a l s tatus . Dietary assessment is the only tool that allows the ::researcher to estimate what subjects are ac tua l l y eat ing . This knowledge is e s sent ia l in the i n te rp re ta t i on of resu l t s from biochemical and anthrop- metric components of a n u t r i t i o n survey (ICNND, 1963). Dietary assessment is usual ly conducted in three phases: c o l l e c t i o n of food intake data; ana lys i s of n u t r i t i v e value of food;' and in terpre ta t ion of data ( J e l l i f f e , 1966). There are three bas ic methods that ex i s t for the c o l l e c t i o n of food intake data: d ie t records, d ie t h i s t o r i e s , and d ie t r eca l l s (Pekkarinen, 1970)- Diet records are accounts of food consumption kept by i n s t i t u - t ions , f a m i l i e s , or . ind iv idua l s for periods o r d i n a r i l y ranging from 1 day to k weeks (Pekkarinen, 1970). Subjects keeping d iet records often weigh a l l foods to be consumed. Problems that have been noted with d iet 10 records include inaccuracy due to fau l ty memory or untruthfulness of sub- j e c t s ; and unconscious changes in the usual d ie tary habits of ind iv idua l s being surveyed (Chalmers et_ a_l_. , 1952 ) . The d ie t h i s tory is a tool which gives an estimate of an i n d i v i d u a l ' s average food intake pattern over a longer time per iod. This usual ly i n - volves conducting a de ta i l ed one-hour interview which includes questions designed to estimate both the usual amounts and the frequencies of food intake over periods of a year or more (Burke, 1947) - The major drawback to th is method is that i t can be very time-consuming. The d ie t reca l l is the method most frequent ly used in n u t r i t i o n surveys. It usual ly involves interviewing ind iv idua l s or f ami l ie s as to the i r food consumption during the preceeding 24-hour or 7~day period (Pekkarinen, 1970 ) . The d ie t reca l l method is quick and inexpensive, and can be used in non-modernized soc i e t i e s where poverty and i l l i t e r a c y are widespread (F lores , 1962 ) . A l so , the 24-hour reca l l is preferab le to the d ie t h i s to ry when studying ch i l d ren (Rasanen, 1 979 ) . However, the d iet reca l l method lacks accuracy for the fo l lowing reasons: i t is dependent on the subject ' s memory and wi l l ingness to t e l l the t ru th ; i t makes no estimate of usual intake (Beaton et a 1 . , 1979 ) ; i t overestimates intake when consumption is low and underestimates i t when consumption is high (Linusson et a l . , 1974 and Madden et_ a_l_. , 1976) and i t cannot be used with any accuracy to assess intake of i nd i v i dua l s , only of populations (Garn et a 1., 1978 and Stapleton and Abernathy, 1980 ) . Once d ietary information is c o l l e c t e d , ana lys i s of nutr ient value of food intake may be conducted. Actual food samples may be c o l l e c t e d and chemical ly analysed for nutr ient composition (ICNND, 1963 ) , or foods may 11 be compared to food composition tables and nutr ient content ca l cu l a ted . The f i na l stage in d ietary assessment involves in terpre t ing d ietary data obtained. Many authors simply compare actual nutr ient intake to recommended intakes. However, as Beaton (1975) pointed out, i t is not poss ib le to judge from th i s whether an observed intake is d e f i c i e n t because recommended intakes are ca lcu la ted to meet the requirements of most of the populat ion, and ind iv idua l requirements vary g rea t l y . Beaton (1975) suggested that d ie tary data, instead, should be interpreted in terms of the p robab i l i t y that nu t r i t i ona l inadequacy e x i s t s . For instance, i f most subjects in a population have d ietary intakes below the recommended intake, then the p robab i l i t y is high that inadequate intakes do ex i s t (Beaton, 1975 ) . Anthropometric assessment allows the researcher to detect long term e f f ec t s of ma lnutr i t ion on growth, s i ze and body composition because most nu t r i t i ona l d e f i c i e n c i e s cause growth dece lerat ion ( J e l l i f f e , 1 966 ) . Anthropometric ind icators are not n u t r i e n t - s p e c i f i c however, and many non-nutr i t iona l factors can inf luence growth and s i z e , inc luding genet ics , sex, d isease, and soc ia l status (Tanner, 1973 ) . Complex methodology is ava i l ab le for n u t r i t i o n a l anthropometry, e s p e c i a l l y the assessment of growth and development of c h i l d r e n , and the est imation of body fat in re l a t i on to height and weight ( J e l l i f f e , 1966 ) . This review w i l l concern i t s e l f mainly with n u t r i t i o n survey anthropometry as i t re lates to the assessment of c h i l d r e n . According to J e l l i f f e ( 1 966 ) , the fo l lowing p r inc ipa l measurements can be taken in n u t r i t i o n surveys of c h i l d r e n : weight; height; head c i r - cumference; chest c ircumference; upper-arm circumference; and t r iceps and/ 12 or subscapular s k in fo ld th ickness. The four measurements most commonly taken are weight, height, upper-arm circumference, and t r i ceps sk in fo ld th ickness. J e l l i f f e (1966) ou t l ined standard recommended procedures for obta in ing these four measurements. The r e l a t i v e merits of the anthropometric measurements commonly used in n u t r i t i o n surveys have been assessed by several authors. Rao and Singh (1970) found that the r a t i o weight/he ight 2 was a better age-independent index for p red i c t ing protein-energy malnutr i t ion in ch i ld ren than other anthropometric ind ices . S i m i l a r l y , Dugdale (1971) found that weight/ h e i g h t 1 - 6 was cor re la ted better with overa l l nu t r i t i ona l status of ch i ld ren than were other antropometric ind ices . Keys and co-workers (1972) examined various ind icators of body shape and body density (which gives a measure of " fa tness " ) and found that weight/height 2 and t r i ceps sk in fo ld th i ck - ness were both wel1 -corre 1ated to body dens i ty . Upper-arm circumference, f i n a l l y , has been found to be a good ind icator of decreasing body mass in protein-energy ma lnu t r i t i on , e s p e c i a l l y i f compared to height (Loewenstein and Ph i l l i p s , - 1973) - The appropr iate eva luat ion of anthropometric measurements depends on choice of standards used for comparative purposes, but community standards are d i f f i c u l t to def ine ( J e l l i f f e , I966). In many countr ie s , local s tan- dards for growth and development have not been prepared, so survey resu l ts are compared to North American standards, even though the a p p l i c a b i l i t y of North American growth standards to developing countr ies is h ighly questionable (Garn, 1965 ) . J e l l i f f e (1966) recommended that where poss ib le , anthropometric resu l t s should be compared to both local and internat iona l standards. Once a standard has been se lec ted , sever i ty of malnutr i t ion 13 in an ind iv idua l subject may be graded according to what percentage of the standard the indiv idual subject achieves (Gomez et a l . , 1956). Biochemical tests provide perhaps the most ob ject i ve means by which to assess n u t r i t i o n a l status because they permit detect ion of nu t r i t i ona l de f i c iency at s u b - c l i n i c a l stages. More accurate assessments of body stores would be furnished by analyses of l i v e r , muscle, and bone t i s sue ; however, in human surveys biochemical assessment usual ly must be r e s t r i c t e d to blodd, ur ine, and ha i r analyses ( J e l l i f f e , 1966) . Numerous wel1-documented methods are ava i l ab l e to assess vitamin and mineral n u t r i t u r e , however, th i s review sha l l concern i t s e l f p r imar i l y with the biochemical assessment of prote in and iron s ta tus . No biochemical measurement ex i s t s at present that is highly s a t i s f a c - tory in eva luat ing prote in n u t r i t u r e . While severe forms of prote in mal- n u t r i t i o n can be better diagnosed by c l i n i c a l than biochemical means, milder forms of prote in def i c iency remain d i f f i c u l t to diagnose (Sauberl ich et a l • , 1974). Biochemical parameters commonly used in prote in status assessment inc lude: serum leve l s of prote in and albumin; serum amino ac id r a t i o s ; ur inary c rea t in ine exc re t i on ; ur inary hydroxyprol ine excre- t i o n ; and ur inary u rea -c rea t in ine r a t i o s . The procedures have been reviewed by Sauberl ich and co-authors (1974) as fo l lows. Serum tota l protein appears to have l i t t l e value alone as a sens i t i ve ind icator of prote in n u t r i t u r e , however serum albumin levels have been shown to decrease in p r o t e i n - d e f i c i e n t ch i l d ren not exh ib i t i n g c l i n i c a l signs of ma lnut r i t i on . Chi ldren with prote in malnutr i t ion also tend to have reduced serum concentrat ions of the essent ia l amino ac ids . As w e l l , they tend to excrete less c rea t in ine as a funct ion of lower body mass, and tend to excrete elevated amounts of hydroxyprol ine, which 14 is a by-product of col lagen metabolism. Fasting u r ina ry .u rea /c rea t in ine rat ios are o f ten reduced in prote in ma lnu t r i t i on , although th i s r a t i o is more r e f l e c t i v e of recent d ietary intake than long-term prote in n u t r i - t i on . Serum tota l prote in and albumin are parameters most commonly assessed because of methodological s i m p l i c i t y ( J e l l i f f e , 1 9 6 6 , and ICNND, 1 9 6 3 ) . The biochemical assessment of iron status has been recent ly reviewed by Cook and Finch ( 1 9 7 9 ) . These authors have noted that although hemo- globin and hematocrit have been the parameters most commonly measured to assess i r o n - d e f i c i e n c y , these methods are i n sen s i t i ve , lack s p e c i f i c i t y , and indicate i ron -de f i c i ency only in late stages. A preferred method, ava i l ab le in recent years, is the determination of the percentage of t r a n s f e r r i n s a tu ra t i on , which is derived from the ra t i o of serum iron to i ron-b ind ing capac i ty , and which is an ear ly ind icator of iron de f i c i ency . An even more sens i t i ve ind icator of iron status than t r a n s f e r r i n satura- t ion is thought to be serum f e r r i t i n , leve l s of which co r re l a te highly with body stores of i ron. Serum f e r r i t i n a f fords a measure of i r on - de f i c iency at i t s e a r l i e s t stage. Unfortunately, the methodology for i t s determination is as yet too complicated for extensive use in f i e l d surveys. Cook and Finch ( 1 9 7 9 ) have recommended combining several methods in assessing iron de f i c iency at d i f f e r e n t stages, inc luding serum f e r r i t i n , t r a n s f e r r i n sa tura t ion , and hemoglobin. However, J e l l i f f e ( 1 9 6 6 ) has pointed out that f requent ly hemoglobin and hematocrit determinations are the only est imations p rac t i cab le in large n u t r i t i o n surveys. 15 3. Assessment o f P h y s i c a l Work Performance P h y s i c a l f i t n e s s f o r work has been d e f i n e d as the c a p a c i t y , i n terms o f both endurance and s t r e n g t h , t o e n j o y moderate m u s c u l a r a c t i v i t y w i t h - out d i s c o m f o r t (Jones e t a l . , 1975 ) . C o n c o m m i t a n t l y , i t has long been known t h a t c o n t i n u a n c e o f a g i v e n a c t i v i t y e v e n t u a l l y l e a d s t o impairment i n performance o f f a t i g u e (Simonson, 1971) - A v a s t l i t e r a t u r e e x i s t s on the p h y s i o l o g y o f work and e x e r c i s e , however, t h i s r e v i e w w i l l summarize o n l y the s a l i e n t p h y s i o l o g i c a l changes t h a t accompany f a t i g u e and how they may be m o n i t o r e d t o a s s e s s p h y s i c a l work perf o r m a n c e . The f o l l o w i n g h i g h l y s i m p l i f i e d a c c o u n t o f res p o n s e s t o e x e r c i s e i n the human body i s d i s t i l l e d from t h e works o f s e v e r a l a u t h o r s (Simonson, 1971; Morehouse and M i l l e r , 1976; and A s t r a n d and R o d a h l , 1977 ) . A c t i v i t y causes an i n c r e a s e i n the r e q u i r e m e n t o f the c o n t r a c t i n g muscles f o r both oxygen and e n e r g y - y i e l d i n g s u b s t a n c e s such as g l y c o g e n . T h i s i n c r e a s e d oxygen r e q u i r e m e n t can be met p a r t i a l l y by i n c r e a s i n g the c a r d i a c o u t p u t . Both h e a r t r a t e and s t r o k e volume may i n c r e a s e so t h a t more b l o o d i s pumped t o the w o r k i n g m u s c l e . F a t i g u e d e v e l o p s i n p r o l o n g e d a c t i v i t y when oxygen s u f f i c i e n c y cannot be m a i n t a i n e d the t h e s e mechanisms and when e n e r g y - y i e l d i n g s u b s t a n c e s become d e p l e t e d . When s u f f i c i e n t oxygen i s a v a i l a b l e t o the w o r k i n g m u s c l e , p y r u v i c a c i d formed i n g l y c o l y s i s i s n o r m a l l y m e t a b o l i z e d t o a c e t a t e and then through t h e Kreb's c y c l e t o form a d e n o s i n e t r i p h o s p h a t e (ATP). Under a n a e r o b i c c o n d i t i o n s , however, p y r u v i c a c i d i s reduced t o l a c t i c a c i d i n - s t e a d . L a c t i c a c i d a c c u m u l a t e s i n the muscle under a n a e r o b i c c o n d i t i o n s and d i f f u s e s i n t o t h e b l o o d . The combined a c c u m u l a t i o n o f both l a c t i c a c i d and p y r u v i c a c i d can e v e n t u a l l y r e s u l t i n m e t a b o l i c a c i d o s i s . Con- 16 commitant to th i s whole process, muscle glycogen s tores , the sole energy source for the anaerobica11y working muscle, become depleted and fat igue becomes pronounced. Given these basic phys io log ica l responses to prolonged muscular a c t i v i t y , there are several indices by which the body's response to work may be assessed: increased resp i ra tory ra te ; increased heart rate; accumu- l a t i on of l a c t i c ac id and pyruvic ac id in the muscle and blood; metabolic a c i do s i s ; and depleted muscle glycogen stores. In add i t ion to these i n - d ices , maximal oxygen uptake can be measured. Maximal oxygen uptake refers to the level of oxygen uptake during exerc i se beyond which further increase in exerc i se in tens i ty is not accompanied by any increase in oxygen uptake. The subject who has a high physical capaci ty w i l l exh ib i t the fo l low- ing c h a r a c t e r i s t i c s in response to exerc i se : low resp i ra tory ra te ; low heart r a te ; low blood and muscle leve l s of l a c t i c ac id and pyruvic a c i d ; a low degree of metabolic a c i do s i s ; high muscle glycogen l eve l s ; and high maximal oxygen uptake. This is in comparison with the subject who has a low physical capac i ty . Most assessments of physical performance employ more than one index of fat igue and the choice of indices to be used often depends on technica l and l o g i s t i c cons iderat ions . As w e l l , i t is pre- ferab le that physical performance be measured in response to w e l l - standardized exerc i se tests such as the treadmil l or bieye 1e-ergometer, where power output can be accurate ly regulated (Jones et a 1., 1975). Maximal oxygen intake is widely regarded to be the best ind icator of maximal physical capacity or physical f i tnes s when exerc i se is prolonged (Morehouse and M i l l e r , 1976). However, i t has a l so been we l l -e s tab l i shed that increases in heart rate and v e n t i l a t i o n rate para 11 el increases in oxygen consumption in exerc i se of increas ing i n tens i t y , and that maximum 17 oxygen uptake can in fact be predicted from heart rate (Morehouse and M i l l e r , 1976). When blood samples can be taken, elevated l a c t i c ac id levels of venous blood are regarded to be a meaningful ind icator that anaerobic metabolism is taking place (Morehouse and M i l l e r , 1976 ) , and blood pH is a good ind icator of metabolic ac idos i s (Jones et_ aj_. , 1975 ) . Tests of muscle glycogen s tores, while exce l len t ind icators of fa t igue, are techn i ca l l y more unwieldy than the other tests mentioned because they involve taking needle biops ies (Simonson, 1971 ) . There are other tests reported in the l i t e r a t u r e that assess physical work performance in a less d i rec t or phys io log ica l fashion than those jus t d i scussed. Endurance time to exhaustion at a given work load, strength at a s p e c i f i c task l i k e hand-grip, actual output produced at a factory or a g r i c u l t u r a l job, and simple observations about level of work e f f i c i e n c y are a l l techniques that have been used to assess physical work performance. These kinds of tests are more conspicuously inf luenced by extraneous factors such as motivation than tests that measure physio- l og i ca l changes in response to exerc i se (Simonson, 1971 ) . This makes resu l t s of these tests d i f f i c u l t to i n te rp re t , but at the same time, these tests may approximate r e a l i t y more c l o se l y than other kinds of te s t s . Results of tests of physical work performance must always be i n t e r - preted in view of the fact that many factors inf luence performance. Durnin (1976) reviewed sex d i f ferences in energy requirements for work and concluded that females have lowerenergy expenditure and lower maximal physical work capacity than males, independent of body s i ze or basal metabolic ra te . Several authors (Dehn and Bruce, 1972 .and Nylind et a l . , 18 1978) have noted t h a t p h y s i c a l f i t n e s s d e c l i n e s w i t h age, and e n v i r o n m e n t a l f a c t o r s such as t e m p e r a t u r e , h u m i d i t y , and a l t i t u d e have been shown to i n f l u e n c e p h y s i c a l performance (Sen Gupta et^ aj_. , 1977; Lane e t a 1 . , 1978; and B u s k i r k and Mendez, 1967)- H a b i t u a t i o n i s a n o t h e r f a c t o r w h i c h s t r o n g l y i n f l u e n c e s p h y s i c a l p e r f o r m a n c e : r e g u l a r l y a c t i v e p eople demonstrate much g r e a t e r p h y s i c a l c a p a c i t y t h a n t h e i r s e d e n t a r y c o u n t e r - p a r t s (Dehn and B r u c e , 1972 and Watson and 0 'Donovan, 1977 ) . S o c i o - economic f a c t o r s a l s o cannot be d i s c o u n t e d : Wyndham and co-workers (1964) found t h a t m o t i v a t i o n , s k i l l , and wages were a l l more i n f l u e n t i a l on j o b p erformance than maximal p h y s i c a l work c a p a c i t y ; and Wyndham and Cook (1964) found t h a t p r o d u c t i v i t y on the j o b was d i r e c t l y r e l a t e d t o q u a l i t y o f s u p e r v i s i o n . - Thus, s o c i o - e c o n o m i c f a c t o r s can o b s c u r e the e f f e c t s o f p h y s i c a l c a p a c i t y on work performance'. In summary, whi 1e maximal oxygen uptake i s t h e b e s t measure o f p h y s i c a l c a p c i t y o f f i t n e s s , p h y s i o l o g i c a l r e s p o n s e s t o sub-maximal e x e r c i s e a l s o p r o v i d e a means t o a s s e s s work performance. I n d i c a t o r s t h a t may be used t o a s s e s s sub-maximal work performance i n c l u d e : h e a r t r a t e , r e s p i r a t o r y r a t e , b l o o d l a c t i c a c i d l e v e l s , b l o o d pH, and muscle g l y c o g e n s t o r e s . F a c t o r s such as s e x , age, e n v i r o n m e n t a l c o n d i t i o n s , h a b i t u a t i o n , and s o c i o - e c o n o m i c s i t u a t i o n s h o u l d a l s o be c o n s i d e r e d when a s s e s s i n g p h y s i c a l work p e r f o r m a n c e . 4. A s s o c i a t i o n Between N u t r i t i o n a l S t a t u s and P h y s i c a l Work Performance I t has been w e l l documented t h a t under a c t u a l and e x p e r i m e n t a l c o n d i - t i o n s o f food s h o r t a g e s o f e xtended d u r a t i o n , the e f f e c t s o f n u t r i t i o n a l d e f i c i e n c i e s m a n i f e s t t h e m s e l v e s i n p h y s i o l o g i c a l , p s y c h o l o g i c a l , and psychomotor changes t h a t can undermine p h y s i c a l work p e r f o r m a n c e . A v a s t 19 l i t e r a t u r e ex i s t s on the e f fec t s of acute s tarvat ion or semi-starvat ion in th is regard (Shi Is, 1980), however, i t is the purpose of th is review to examine only the l i t e r a t u r e that deals with the e f f ec t s of sub-optimal nu t r i t i ona l status on the physical work performance of humans. Sub-optimal nu t r i t i ona l s ta tus , more s p e c i f i c a l l y , re fers to the eros ion of health caused by chronic but non-acute n u t r i t i o n a l d e f i c i e n c i e s that may be experienced for a l i f e t ime (Berg, 1973)- The re la t ionsh ip between n u t r i t i o n a l status and physical work per- formance has been extens ive ly studied in humans only with in the last 20 years, as increas ing a t tent ion has been paid to the s i t ua t i on of chronic undernourishment in developing countr ies . The FAO (1962) reviewed the consequences of an inadequate d ie t for working people and found them to be f o u r f o l d : lethargy; low res i s tance to d isease; high absenteeism; and high accident rates. These factors are postulated to resu l t in decreased work output. Conversely, when inadequately nourished workers have received supplemental r a t i ons , as studies c i t ed by the FAO (1962) ind i ca te , work output has improved. Numerous studies s ince th is review have examined the re l a t i on between undernourishment and phys i ca lwork performance more d i r e c t l y but the l i t e r a t u r e is not without controversy. Individual v a r i a b i l i t y is a confounding factor when studying n u t r i - t iona l status and physical work performance because wide ranges of v a r i a - t ion ex i s t in human metabolic and work e f f i c i e n c y (Edmundson, 1979), and i t has long been accepted that nutr ient requirements vary widely between ind i v idua l s , independent of sex, a c t i v i t y , or basal metabolic rate (Rose and Wi l l iams, I96I and Widdowson, 1962). This l a t t e r observation has led some authors (Durnin et^ aj_. , 1973) to comment that human energy requirements in re l a t i on to expenditure are indeed poorly understood. 20 Several studies have invest igated energy expenditure and requirements in manual labourers and have found work performance to be unaffected by seemingly inadequate energy intakes (Ramanamurthy and Dakshayani, 1962; Ramanamurthy and Belavady, 1966; Belavady, 1966; and Ashworth, 1968). These invest igators assessed c a l o r i c intake, and then e i ther measured actual hourly work output or assessed work e f f i c i e n c y by simple observa- t i o n . Actual phys io log ica l responses to exerc i se were not tested in these s tud ies . Areskog and co-workers (1969) examined several parameters of n u t r i - t iona l status and tested physical work performance by measuring heart rate in response to increas ing bieye 1e-ergometric workload in poorly nourished Ethiopian boys. Bieye 1e-ergometer tests showed that undernourished ch i l d ren had poorer maximal work capacity for age but greater maximal work capacity for s i ze than did Swedish cont ro l s . These authors concluded that there was no demonstrable co r re l a t i on between physical work per fo r - mance and n u t r i t i o n a l s tatus. Results of studies such as these have prompted the suggestion that there may be adaption to inadequate d iets such that phys ica l f i tnes s is not impaired by undernourishment (Durnin e t a l . , 1973). In a study of work output of coa l -miners , test subjects were given 500 supplemental kcal da i l y while control subjects consumed the i r usual sub-optimal d iets (Satyanarayana et a 1., 1972). A f ter 6 months, supple- mentation had no e f f e c t on work output or attendance on the job, but supplemented subjects gained a s i g n i f i c a n t amount of weight and reported improved stamina. Another study (Heywood et_ a_l_. , 1974) examined various factors in f luenc ing p roduct i v i t y of Jamaican sugar cane cu t te r s , i nc lud - ing weight, height, sk in fo ld th ickness, arm circumference, hemoglobin, 21 h e m a t o c r i t , and f o o d i n t a k e . We ight and w e i g h t / h e i g h t , assumed t o r e f l e c t n u t r i t i o n a l s t a t u s , were found t o have t h e s t r o n g e s t c o r r e l a t i o n w i t h p r o - duc t i v i t y . In a s t u d y o f pea s an t f a r m e r s i n Ea s t J a v a , Edmundson (1977) found no c o r r e l a t i o n between d a i l y ene rgy i n t a k e and o u t p u t . Work o u t p u t , o r ene rgy e x p e n d i t u r e , was d e t e r m i n e d f o r 10 b a s i c a c t i v i t i e s , then t o t a l d a i l y e ne r g y e x p e n d i t u r e o f each s u b j e c t was c a l c u l a t e d f rom a c t i v i t y r e c o r d s . No c o r r e c t i o n was made f o r b a s a l m e t a b o l i c r a t e , nor f o r adequacy o f t he d i e t w i t h r e g a r d s t o n u t r i e n t s o t h e r than e n e r g y . C h r o n i c a l l y u n d e r n o u r i s h e d Co l omb ian r u r a l d w e l l e r s were g i v e n a c o m p l e t e a s se s sment o f n u t r i t i o n a l s t a t u s i n c l u d i n g e s t i m a t i o n o f body c o m p o s i t i o n , and as w e l l , maximum oxygen con sumpt i on and endu rance t ime a t a t r e a d m i l l work t e s t were e v a l u a t e d ( B a r a c - N i e t o e t a 1., 1978 ) . I t was found t h a t maximum a e r o b i c power was c o r r e l a t e d t o mu s c l e c e l l mass, a n t h r o p o m e t r i c v a r i a b l e s , and hemog l ob i n l e v e l s , however endu rance d i d not appea r t o be a f f e c t e d by n u t r i t i o n a l s t a t e . A n o t h e r s t u d y i n B r a z i l ( A n g e l e l i , 1978) examined h e a r t r a t e o f a g r i c u l t u r a l w o r k e r s i n r e spon se t o submaximal b i e y e 1 e - e r g o m e t r i c work b e f o r e and a f t e r d i e t a r y s u p p l e - m e n t a t i o n . A f t e r s e v e r a l week s , e x e r c i s e h e a r t r a t e s were s i g n i f i c a n t l y r educed i n w o r k e r s r e c e i v i n g s upp lement s as compared t o c o n t r o l s . S a t y a n a r a y a n a and c o - w o r k e r s (1977) measured work o u t p u t o f f a c t o r y w o r k e r s i n I n d i a , as w e l l as a n t h r o p o m e t r i c i n d i c e s , h e m o g l o b i n , serum a l b u m i n , and s o c i o - e c o n o m i c v a r i a b l e s . S u b j e c t s d i d not appear t o be s u f f e r i n g f r om any o v e r t n u t r i t i o n a l d e f i c i e n c i e s , but a n t h r o p o m e t r i c d a t a v a r i e d w i d e l y . H igh work o u t p u t was s i g n i f i c a n t l y c o r r e l a t e d w i t h h i g h body w e i g h t . A l a t e r s t u d y by t he same i n v e s t i g a t o r s ( S a t y a n a r a y a n a ; et_ aj_. , 1979) examined t h e e f f e c t s o f n u t r i t i o n a l d e p r i v a t i o n i n e a r l y 22 childhood on body s i ze and heart rate response to b icyc le -ergometr ic work of boys in India. Maximal physical work capacity was strongly corre la ted to current weight and height, and to leve ls of habitual physical a c t i v i t y . Desai 's group (1981) a lso found that low body s ize was re lated to low work performance in B r a z i l i a n c h i l d r e n . However, th i s resu l t was not in agreement with a study of I ta l ian ch i ld ren (Ferro-Luzzi et a l . , 1979 ) , which found that ch i l d ren who were marginal ly malnourished had lower heart rates in response to exerc i se , despite growth re ta rda t ion , than the i r we 11-nourished counterparts . While the data for ch i l d ren seems to be more controvers ia l (Spurr et^ aj_., 1 978 ) , i t is becoming general ly accepted that ma lnutr i t ion a f f ec t s phys ica l work performance in adults (Spurr e_t_ a_l_., 1979 ) . Spurr and co- workers (1979) presented resu l t s of t he i r studies on heart rate in response to sub-maximal t readmi l l work in malnourished Columbian adults during a period of d ie tary replenishment. Increased sever i ty of ma lnutr i t ion including underweight for height was associated with increased heart rate response to work to such a degree that these authors suggested that sub- maximal work tests may be useful as a funct ional assessment of nu t r i t i ona l s ta tus . While the studies ju s t discussed have examined physical work pe r fo r - mance in r e l a t i o n to a wide range of parameters of n u t r i t i o n a l s tatus , there is another body of l i t e r a t u r e which has concerned i t s e l f pr imar i l y with the e f f e c t s of i r on -de f i c i ency on physical work performance. Davies and co-authors (1973) assessed responses to b icyc le -ergometr ic exerc i se in A f r i can indus t r i a l workers with moderate (hemoglobin 8-10 g/100 ml) and severe (Hemoglobin less than 8 g/100 ml) anemia. Both moderately and severely anemic subjects exh ib i ted increased exerc i se heart rates compared 23 to non-anemic (hemoglobin g r e a t e r than 13 g/100 ml) c o n t r o l s . S e v e r e l y anemic s u b j e c t s a l s o e x h i b i t e d s i g n i f i c a n t l y lower maximum a e r o b i c power than c o n t r o l s . Gardner and co - w o r k e r s (1975) s t u d i e d i r o n - d e f i c i e n c y anemia and i t s e f f e c t on p h y s i c a l performance i n Ven e z u e l a n a d u l t s . Heart r a t e , b l o o d l a c t i c a c i d , and maximal oxygen consumption responses t o a s t a n d a r d s t e p t e s t were d e t e r m i n e d , as w e l l as m u s c u l a r s t r e n g t h , i r o n s t a t u s , and a n t h r o p o m e t r i c measurements. One group o f anemic s u b j e c t s then r e c e i v e d i r o n i n j e c t i o n s and t r e a t m e n t f o r hookworm i n f e s t a t i o n . E i g h t y - t h r e e days a f t e r i n i t i a t i o n o f t r e a t m e n t , e x e r c i s e h e a r t r a t e s and b l o o d l a c t i c a c i d l e v e l s were lower and maximal oxygen consumption h i g h e r i n the t r e a t e d group than i n the u n t r e a t e d . M u s c l e s t r e n g t h appeared to be u n a f f e c t e d by i r o n s t a t u s . Gardener's group conducted a l a t e r s t u d y on i r o n - d e f i c i e n c y anemia i n t e a e s t a t e w o r k e r s i n Ce y l o n (Gardner et_ aj_. , 1977) - Heart r a t e was m o n i t o r e d as s u b j e c t s performed t r e a d m i l l t e s t s and b l o o d l a c t i c a c i d l e v e l s were d e t e r m i n e d b e f o r e and a f t e r e x e r c i s e . Both e x e r c i s e h e a r t r a t e a t a l l work l o a d s and p o s t - e x e r c i s e b l o o d l a c t i c a c i d l e v e l s were s i g n i f i c a n t l y h i g h e r i n s u b j e c t s w i t h hemoglobin l e v e l s below 7 g/100 ml than i n non-anemic c o n t r o l s . When anemic w o r k e r s then r e c e i v e d i r o n sup- plements f o r one month, an i n c r e a s e i n hemoglobin and a s i g n i f i c a n t i n - c r e a s e i n amount o f t e a p i c k e d was o b s e r v e d f o r i r o n - t r e a t e d s u b j e c t s as compared w i t h p l a c e b o - t r e a t e d s u b j e c t s ( E d g e r t o n e t a 1., 1979 ) . L e v e l s o f e veryday a c t i v i t y a l s o appeared t o i n c r e a s e s i g n i f i c a n t l y a f t e r i r o n t r e a t m e n t . The same r e s e a r c h e r s , i n a n o t h e r s t u d y ( O h i r a e t a l . , 1979) found t h a t hemoglobin and maximal work endurance began t o i n c r e a s e i n anemic 2k C e y l o n e s e w o r k e r s as soon as f o u r days a f t e r commencement o f i r o n t r e a t m e n t . A n o t h e r r e c e n t s t u d y o f anemia and work p r o d u c t i v i t y was c a r r i e d o u t i n I ndone s i a by B a s t a and c o - w o r k e r s ( 1979 ) - In male w o r k e r s on a West J a va r ubbe r p l a n t a t i o n , hemog l ob i n l e v e l s were c o r r e l a t e d t o s t e p t e s t p e r f o r - mance, t o a c t u a l work o u t p u t , and t o m o r b i d i t y f r om d i a r r h e a and i n f e c - t i o n s . I ron t r e a t m e n t r e s u l t e d i n s i g n i f i c a n t improvements i n t h e s e p a r a - mete r s i n c o m p a r i s o n w i t h p l a c e b o - t r e a t e d c o n t r o l s . D i e t a r y a s se s sment showed t h a t c a l o r i c i n t a k e was not c o r r e l a t e d t o e i t h e r s t e p t e s t p e r - fo rmance o r work o u t p u t . In a d d i t i o n t o t h e e f f e c t s o f i r o n - d e f i c i e n c y on p h y s i c a l work p e r - f o rmance , o t h e r s p e c i f i c n u t r i e n t d e f i c i e n c i e s may i n f l u e n c e work p e r f o r - mance. V i t a m i n A d e f i c i e n c y i n p o u l t r y has been found t o i n f l u e n c e musc l e c a r b o h y d r a t e m e t a b o l i s m (Sundeen, 1980 ) , i n t h a t s e v e r e d e f i c i e n c y has been shown t o c au se r e s t r i c t i o n i n g l y c o g e n d e p o s i t i o n . T h i s may a f f e c t work p e r f o r m a n c e s i n c e musc l e a b i l i t y t o p e r f o r m p r o l o n g e d e x e r - c i s e i s i n f l u e n c e d m a r k e d l y by musc l e g l y c o g e n s t o r e s ( A s t r a n d , 1967 and Be r g s t r om e t a l . , 1967 ) . Long te rm p r o t e i n and energy m a l n u t r i t i o n , t h r ough imped ing m y e l i n a t i o n , was found t o cause s i g n i f i c a n t r e d u c t i o n i n ne rve c o n d u c t i o n v e l o c i t y i n c h i l d r e n , w h i c h may a f f e c t mu s c l e c o - o r d i n a t i o n and a b i l i t y t o p e r f o r m work t a s k s (Kumar e t a l . , 1977 ) . F i n a l l y , e x t r a n e o u s d i e t a r y f a c t o r s can i n f l u e n c e e x e r c i s e p e r f o r m a n c e i n v a r i o u s ways . C a r b o h y d r a t e - r i c h d i e t s can p r o l o n g e x e r c i s e t i m e t o e x h a u s t i o n i f a d m i n i s t e r e d b e f o r e o r d u r i n g e x e r c i s e t e s t i n g ( M a r t i n et_ aj_. , 1978) , s i n c e c a r b o h y d r a t e i s r e ga rded t o be t he p r e f e r r e d energy s o u r c e f o r t h e w o r k i n g musc l e f o l l o w i n g p e r i o d s o f c a l o r i c r e s t r i c t i o n ( C o n s o l a z i o and J o h n s o n , 1972; and B e r g s t r o m et_ aj_. , 1967 ) . C a f f e i n e i n t a k e can a l s o have an a f f e c t on e x e r c i s e p e r f o r m a n c e . By s t i m u l a t i n g 25 f ree fa t ty ac id m o b i l i z a t i o n , an energy source for the ae rob i ca l l y working muscle, ca f fe ine exerts a sparing e f f e c t on muscle glycogen, re su l t ing in prolonged endurance at heavy exerc i se (Costi 11 et_ aj_., 1978 ) . 5 . Nutri t i on in Brazi 1 a) B r a z i l i a n Socio-economic S i tuat ion B raz i l was f i r s t se t t l ed in 1532 by the Portuguese, who organized a co lon ia l soc ie ty in the northeast of the country to protect the i r interest in B r a z i l ' s abundant natural resources. This ear ly B raz i l i an soc iety was founded on p lanta t ion a g r i c u l t u r e , pa t r i a rcha l family l i f e , and the labour of Negro and Indian slaves (Freyre, 1956 ) . In 1822 B raz i l gained inde- pendence from Portugal and in 1889 an independent Republic was declared (Worcester, 1 973 ) . B r a z i l i a n p o l i t i c a l h i s tory has been stormy s ince 1889 - Author i tar ian and m i l i t a r y d i c ta to r sh ip s have only occas iona l l y been interspersed with e lected popul i s t governments (Rosenbaum and T y l e r , 1972 ) . The most recent change of government, in 1964, resu l ted from the f o r c i b l e over- throw of an e lected party by a m i l i t a r y coup (Frank, 1969)- B r a z i l ' s economic past was dominated by the exp lo i t a t i on and export of i t s cash crops and minera ls , often to the exc lus ion of production of adequate local food suppl ies (Frank, 1969 and Worcester, 1973 ) . Major products that were exported at various times s ince 1600 have inc luded: sugar, gold, rubber, cacao, and coffee (Margolis, 1973 ) . B raz i l main- tained a p r imar i l y co lon ia l a g r i c u l t u r a l export economy un t i l the 1950 ' s , at which time dramatic i ndus t r i a l development began, e s p e c i a l l y in the automotive and steel industr ies (Rosenbaum and T y l e r , 1972 ) . Braz i l is a large country which occupies hl% of the geographic area 26 of South America (Government of B r a z i l , 1976 ) . This is i l l u s t r a t e d in Figure 11-2. B raz i l has a diverse cl imate ranging from the dry backlands and t rop i ca l forests of the north to the f e r t i l e , temperate regions of the South. Its population is 90% Catho l ic and the national language is Portuguese (Government of B r a z i l , 1976 ) . The populat ion of B raz i l is cur rent l y estimated to be 119,656,000 people (Inter-American Development Bank - IADB, 1979 ) . The population growth rate is 2.8% annually (United Nations - UN, 1979a ) . The average l i f e expectancy at b i r th is 57-6 years for males and 61 .0 years for females (UN, 1979a ) , whi le the infant mor ta l i t y . r a te is 9-10% (IADB, 1979 ) . The Braz i1 i an economy today, as in the past, is s t i l l based pr imar i l y on a g r i c u l t u r e . B r a z i l ' s leading exports are coffee beans, soya beans, and unrefined sugar (UN, 1980 ) . Other p r i nc ipa l products for export i n - clude kidney beans, r i c e , beef, cocoa, tea , tobacco, and cotton (Govern- ment of B r a z i l , 1976 ) . In most parts of the country, the proport ion of the population that is rural exceeds 50% (Shrimpton, 1 975 ) . Although the small annual growth rate of the indus t r i a l sector soared over ]Q% in the ear ly 1970 's, th i s rate of increase has s tarted to de- c l i n e (UN, I 98O) . B r a z i l ' s balance of trade is now negative with imports exceeding exports. In f l a t ion is a major problem; so much so that in 1979 consumer pr ices rose by over 50% (IADB, 1979). According to Shrimpton (1975), incomes in Braz i l are unevenly d i s t r i bu ted such that 10% of the population receives 48% of the wealth. The wages of the B raz i l i an working c lass have not kept pace with the severe i n f l a t i o n that has plagued the country s ince 1950 (Arruda, 1975 ) , and the present estimated per cap i ta income is thought to be approximately US $1,384 per year (UN, 1979a ) . E39 State of Sio Paulo FIGURE I 1-2 Map of Brazi1 . a a From Government of B r a z i l , 1976. 28 There ex i s t s an o f f i c i a l minimum sa l a ry , but employers are not forced to pay th is wage to non-unionized workers. In add i t i on , the majority of B r a z i l i a n people have no soc ia l secur i ty or unemployment insurance (Govern- ment of B r a z i l , 1976 ) . Unemployment has been estimated to vary between 15 and 30% of the male adult work force (Shrimpton, 1975) - As previous ly mentioned, high unemployment is the dr i v ing force of migrat ion. Workers leave the i r homes and fami l ie s in the north hoping to secure employment in wealthier southern states of B raz i l (Margolis, 1 973 ) . The universal r ight to education is recognized by the B r a z i l i a n govern- ment ( 1 9 7 6 ) , yet of a l l B r a z i l i a n ch i l d ren enter ing primary schoo l , only a f r a c t i on ever reach un i ve r s i t y ( F r e i r e , 1970 ) . Most poor ch i ld ren rare ly reach even the second grade (Government of B r a z i l , 1976 ) , and i l l i t e r a c y is a nat ional problem of considerable proport ion ( F r e i r e , 1970 and 1 973 ) . The B r a z i l i a n government (1976) asserts that health care is paid for by the state in c h i l d b i r t h , infancy, and ch i ldhood, but Shrimpton's ana lys i s (1975) of the medical system revealed that k%% of townships in B raz i l had no doctor, 85% of a l l hosp i ta l s beds were p r i v a t e , and 60% of the B r a z i l i a n populat ion had no health insurance. The leading causes of death in B raz i l are e n t e r i t i s and d iarrhea l disease (UN, 1979) , both of which are diseases associated with ma lnut r i t ion (Berg, 1 973 ) . Sch i s to - somiasis, malar ia , Chagas 1 d i sease, and tubercu los i s are continuing endemic publ ic health problems in B raz i l (Government of B r a z i l , 1976 ) . Braz i l s t i l l exh ib i t s many of the c h a r a c t e r i s t i c s of an underdeveloped country: high infant mor ta l i t y ; low l i f e expectancy; high population growth rate; large rural populat ion; d i s t r i b u t i o n of income heavi ly skewed in favour of a small percentage of the populat ion; widespread 29 i l l i t e r a c y ; and a high incidence of diseases re lated to ma lnutr i t ion and poor hygiene. Because so much of B raz i l is s t i l l so underdeveloped, i t has been suggested that B r a z i l ' s s o - ca l l ed development mi rac le , namely the rapid increase in indus t r i a l growth s ince the 1950 ' s , has ac tua l l y benef i t ted only a small minority of B r a z i l i a n people (Frank, 1969; Forman, 1975; Davis, 1977; and Souza, 1975 ) . b) Nut r i t i ona l Status of B r a z i l i a n People i) National Studies Numerous studies have invest igated the n u t r i t i o n a l status of B r a z i l i a n people. This review w i l l summarize resu l t s of pert inent studies conducted with in the last 20 years. There have been two comprehensive surveys that examined d ie ta ry , anthropometric, b iochemica l , and c l i n i c a l aspects of the nu t r i t i ona l status of B r a z i l i a n f am i l i e s . The ICNND conducted a survey in 1963 of over 5,500 ind iv idua l s in northeastern Braz i l (ICNND, 1 965 ) . The out- standing f indings of th i s survey were that energy and prote in intakes were low among most of the sample populat ion; that heights and weights of ch i ld ren were well below American standards; and that few c l i n i c a l signs of ma lnutr i t ion were observed. This survey a lso found that 60% of the population had e i the r low or d e f i c i e n t leve ls of serum vitamin A, which indicates probable dep let ion of body vitamin A s tores . Examinations of serum tota l p ro te i n , ur inary thiamin, and ur inary r i b o f l a v i n indicated that approximately 25% of the population appeared to be d e f i c i e n t in these nu t r i en t s . A more recent survey of 500 Sao Paulo fami l ie s (Campino et a l . , 1975) found that of the poorest 20% of people s tud ied, 50% had c l i n i c a l signs 30 malnu t r i t i on , 25% were below American standards for height and weight, and most had prote in and energy intakes s i g n i f i c a n t l y lower than wealthier subjects s tud ied . Dietary assessment of the B r a z i l i a n population has been the subject of many s tud ies . As c i t ed by Shrimpton ( 1 9 7 5 ) , in 1961-1963, family food consumption surveys were conducted by the Vargas Foundation in B r a z i l . Covering 9 ,000 f a m i l i e s , 48 c i t i e s , and rural areas in 7 s t a te s , these surveys provided the fo l lowing estimates of food consumption: 75% of people in the northeast consumed energy -def i c ient d i e t s ; the rural popula- t ion in the south appeared to be well nourished, while nearly ha l f the urban population in the south consumed energy d e f i c i e n t d i e t s ; and in a l l areas, most people consumed adequate amounts of p ro te in . Chaves (1964) noted that basal d iets in the northeast of B raz i l con- s i s ted of dry sa l ted beef, f l o u r , beans, and sugar. S iqueira (1970) noted that although food production in B raz i l increased dramat ica l ly between 1948 and 1961, B raz i l s t i l l compared unfavourabley with other Lat in American countr ies in terms of i nd i v idua l s ' food purchasing power. Indeed, Patr ick and Simoes (1971) found that poor people in centra l B raz i l spent 80% of t he i r income on food but most people f a i l e d to meet recommended d ietary allowances for any of the nutr ients considered. Jansen and co-workers (1977) found that tota l a v a i l a b i l i t y of c a l o r i e s and prote in was great ly dependent on income, and that low-income urban B raz i l i an s simply could not purchase an adequate quantity of food to meet t h e i r needs. In another study (Alves, 1977) of 2 ,380 Sao Paulo f am i l i e s , 15% of f ami l ie s consumed inadequate amounts of prote in and energy, and the mean income of fami l ie s who did consume an adequate d ie t was twice that of f ami l ie s who did not. 31 Martins and co-authors (1977) reported that mean intakes of vitamin A, thiamin, r i b o f l a v i n , vitamin C, and calcium were well below recommended levels in 337 Sao Paulo fami l ie s of low-income. In other Sao Paulo s tud ies , Szarfarc (1979) found that intakes of high qua l i t y prote in foods such as meat, mi lk, and eggs had dec l ined by over 20% between 1969 and 1975 in low-income f a m i l i e s ; and Roncada (1972) found that most people consumed less than k0% of the recommended amounts of vitamin A in the d i e t . Biochemical and c l i n i c a l indices of n u t r i t i o n a l status of the general B r az i l i an populat ion have been examined by several authors. Roncada (1972) examined biochemical and c l i n i c a l as well as d ie tary indices of vitamin A status in Sao Paulo f a m i l i e s . In th is study, i t was reported that 10-30% of subjects had low serum vitamin A values and that several c l i n i c a l signs of hypovitaminosis A were found. Another biochemical study (Szarfarc, 1972) found that k0% of people in Sao Paulo v i l l a g e fami l ie s had low hemoglobin values. As w e l l , in another study, k0% of ind iv idua l s from low-income Sao Paulo fami l ie s were found to excrete sub-normal leve l s of r i b o f l a v i n in the i r urine (Wilson et al_., 1977 ) . Apart from studies of the general populat ion, the nu t r i t i ona l status of B r a z i l i a n infants and ch i l d ren has been of p a r t i c u l a r concern to many inves t i ga tor s . An ear ly work by Waterlow and Vergara (1956) out l ined the resu l t s of a prote in ma lnutr i t ion survey made of ch i l d ren in f i v e towns in B r a z i l . It was found that many infants were weaned ear ly into d ie t s that were inadequate in most nutr ients inc luding prote in and that in most cases, unsanitary condit ions caused many ch i ld ren to contact d iarrhea and in fect ions during the f i r s t year of l i f e . These factors great ly aggravated ex i s t i n g ma lnutr i t ion and many of these ch i ld ren e i the r 32 d i e d o r d e v e l o p e d c l i n i c a l s i g n s o f k w a s h i o r k o r (Waterlow and V e r g a r a , 1956) . P u f f e r and Serano (1973) i n c l u d e d B r a z i l i n t h e i r s t u d y o f i n f a n t m o r t a l i t y i n Pan-American c o u n t r i e s . R e c i f e , i n n o r t h e a s t B r a z i l , was found t o have t h e f o u r t h h i g h e s t i n f a n t m o r t a l i t y r a t e among 25 c i t i e s s t u d i e d . Most i n f a n t s who d i e d i n R e c i f e were r e p o r t e d t o d i e o f i n f e c - t i o u s d i s e a s e s . P u f f e r and Serano (1973) a l s o e s t i m a t e d t h a t n u t r i t i o n a l d e f i c i e n c y was an u n d e r l y i n g cause o f kd% o f de a t h s i n c h i l d r e n under 5 y e a r s i n R e c i f e . B r e a s t f e e d i n g p a t t e r n s i n B r a z i l were review e d by Sousa and c o l l e a g u e s i n 1975- B r e a s t f e e d i n g appeared t o be d e c l i n i n g g e n e r a l l y , e s p e c i a l l y among low-income women. Over 70% o f women employed b o t t l e - f e e d i n g by the time t h e i r i n f a n t was 2 months o l d . Ignorance about the b e n e f i t s o f b r e a s t f e e d i n g , and t h e i n f l u e n c e o f i n f a n t f o r m u l a a d v e r t i s i n g were c i t e d as two major reasons f o r t h e r i s e i n b o t t l e - f e e d i n g (Sousa e t a l . , 1975) . More r e c e n t s t u d i e s have shown t h a t w h i l e many women b r e a t f e e d t h e i r c h i l d r e n f o r s i x t o t w e l v e months a f t e r b i r t h , weaning foods l i k e s u g a r w a t e r , c a s s a v a f l o u r , and r i c e f l o u r a r e i n t r o d u c e d as e a r l y as two weeks a f t e r b i r t h (Desai et_ a_j_. , 1980, and Swann, 1 979 ) . D i e t a r y s t u d i e s have been c o n d u c t e d among s e v e r a l groups o f o l d e r c h i l d r e n i n B r a z i l . Rosenberg (1977) found t h a t b r e a k f a s t c o n s i s t e d o f bread and c o f f e e w i t h a l i t t l e sugar and m i l k f o r the m a j o r i t y o f Sao P a u l o s c h o o l c h i l d r e n , a l t h o u g h no comment was made as t o the n u t r i t i o n a l e f f i c a c y o f t h i s b r e a k f a s t . S a n t o s ' group (1979) s t u d i e d t h e n u t r i t i o n a l v a l u e o f a r i c e ( O r i z a s a t i v a ) and bean ( P h a s e o l u s v u l g a r i s ) d i e t , t r a - d i t i o n a l B r a z i l i a n f a r e , f o r p r e - s c h o o l c h i l d r e n . They found t h i s d i e t c o u l d be a s a t i s f a c t o r y p r o t e i n s o u r c e i f accompanied by adequate energy 33 i n t a k e . Many r e s e a r c h e r s have l o o k e d a t a n t h r o p o m e t r i c i n d i c e s of n u t r i t i o n a l s t a t u s i n B r a z i l i a n c h i l d r e n . Marcondes and co-workers ( 1 9 7 0 p u b l i s h e d a c r o s s - s e c t i o n a l a n t h r o p o m e t r i c s t u d y o f o v e r 9,000 low-income Sao P a u l o c h i l d r e n between ages 3 months and 12 y e a r s . The r e s u l t s o f t h i s s t u d y a r e o f t e n used i n B r a z i l as a l o c a l s t a n d a r d f o r h e i g h t and w e i g h t ( S h r i m p t o n , 1975 ) , even though v a l u e s o b t a i n e d f o r h e i g h t and w e i g h t were low i n c o m p a r i s o n w i t h both American s t a n d a r d s and v a l u e s f o r B r a z i l i a n c h i l d r e n from h i g h e r s o c i o - e c o n o m i c groups. G u i t t i (1974) a l s o examined low-income s c h o o l - a g e c h i l d r e n i n B r a z i l , c omparing them t o American s t a n d a r d s . Low body w e i g h t and s m a l l head c i r c u m f e r e n c e f o r age were found i n 63% o f s u b j e c t s . A n o t h e r s t u d y o f c h i l d r e n under 5 y e a r s (S i gu 1 em et_ aj_. , 1976) showed t h a t c h i l d r e n from h i g h - i n c o m e B r a z i l i a n f a m i l i e s tended t o meet o r exceed American s t a n d a r d s f o r h e i g h t and w e i g h t ; whereas, low-income c h i l d r e n f e l l below American s t a n d a r d s . S e v e r a l l a t e r s t u d i e s ( G u i t t i e_t a]_. , 1977; T u r i n i e_t a l _ . 1 9 7 8 ; Hegg, 1978; Yunes e t aj_. , 1978; and Desai e t a l . . , 1981) have e x p r e s s e d s i m i l a r r e s u l t s f o r c h i l d r e n who a r e s c h o o l age and younger. C l i n i c a l s t u d i e s o f B r a z i l i a n c h i l d r e n c o n f i r m the e x i s t e n c e o f n u t r i t i o n problems among low-income groups. Maldonada (1968) r e p o r t e d w i d e s p r e a d d e n t a l c a r i e s and some ca s e s o f e n l a r g e d t h y r o i d among p o o r l y n o u r i s h e d s c h o o l c h i l d r e n i n c e n t r a l B r a z i l . Simmons (1976) found a h i g h i n c i d e n c e o f c l i n i c a l s i g n s o f h y p o v i t a m i n o s i s A, i n c l u d i n g b l i n d n e s s among p r e - s c h o o l c h i l d r e n i n n o r t h e a s t B r a z i l . B i o c h e m i c a l assessment o f B r a z i l i a n c h i l d r e n has shown t h a t low- income s u b j e c t s have s i g n i f i c a n t l y p o o r e r r i o b f l a v i n s t a t u s , as i n d i c a t e d by u r i n a r y r i b o f l a v i n / c r e a t i n i n e r a t i o s than w e l l - t o - d o c h i l d r e n ( M a r t i n s e_t̂  aj_. , 1 9 7 6 ) . In a n o t h e r b i o c h e m i c a l s t u d y o f i r o n - d e f i c i e n c y anemia i n Sao P a u l o , low hemoglobin l e v e l s , w h i l e not p r e v a l e n t i n t h e p o p u l a t i o n as a w hole, d i d o c c u r w i t h s i g n i f i c a n t l y g r e a t e r f r e q u e n c y i n c h i l d r e n o f low s o c i o - e c o n o m i c s t a t u s ( S i g u l e m , 1 9 7 8 ) . Roncada's group ( 1 9 7 8 ) examined serum v i t a m i n A and c a r o t e n e i n c h i l d r e n o f n a t i o n a l m i g r a n t s i n Sao P a u l o . They found t h a t o v e r 50% o f c h i l d r e n had low o r d e f i c i e n t v a l u e s o f both serum v i t a m i n A and c a r o t e n e . T h i s c o n f i r m e d the r e s u l t s o f p r e v i o u s s t u d i e s (Gomes e t a l . , 1 9 7 0 and Va re 1 a et_ a]_. , 1 9 7 2 ) showing t h a t c h i l d r e n from lower B r a z i 1 i an s o c i o - economic groups tend t o have m a r g i n a l v i t a m i n A n u t r i t u r e . O l s o n , i n h i s s t u d y o f l i v e r v i t a m i n A r e s e r v e s ( 1 9 7 9 ) , found t h a t 30% o f c h i l d r e n i n c e n t r a l B r a z i l between 3 weeks and 2 y e a r s o l d who had d i e d o f v a r i o u s causes had e x t r e m e l y low l i v e r v i t a m i n A r e s e r v e s . F u r t h e r - more, v i t a m i n A r e s e r v e s i n 50% o f c h i l d r e n who d i e d under 4 y e a r s o f age were c l a s s i f i e d as i n a d e q u a t e i n t h i s s t u d y , i n d i c a t i n g p r o b a b l e w i d e s p r e a d cause f o r c o n c e r n about v i t a m i n A n u t r i t u r e o f B r a z i l i a n c h i l d r e n i n t h i s a r e a ( O l s o n , 1 9 7 9 ) - i i ) S t u d i e s i n R i b e i r a o P r e t o , S i o P a u l o R e l a t i v e l y few n u t r i t i o n s t u d i e s have been p r e v i o u s l y conducted i n the R i b e i r a o P r e t o a r e a o f Sao P a u l o s t a t e i n B r a z i l . P u f f e r and Serano ( 1 9 7 3 ) i n c l u d e d R i b e i r a o P r e t o as a p r o j e c t a r e a i n t h e i r s t u d y o f i n f a n t m o r t a l i t y . R i b e i r a o P r e t o was found t o be s u p e r i o r t o o t h e r a r e a s i n L a t i n A m e rica i n t h a t i t had lower i n f a n t m o r t a l i t y r a t e s and a lower i n c i d e n c e o f i n f a n t deaths h a v i n g m a l n u t r i t i o n as an a s s o c i a t e d c a u s e . The n u t r i t i o n a l s t a t u s o f 5 8 6 R i b e i r a o P r e t o c h i l d r e n aged 2 t o 1 0 y e a r s was i n v e s t i g a t e d by Dutra de O l i v e i r a and co-workers i n 1 9 6 4 . A l l 35 subjects in th i s study were found to have values for height, weight, and arm circumference well below American standard values. Energy intakes in th i s study were found to be low, and iron s tatus, as indicated by hemo- globin l e ve l s , was found to be general ly adequate. Angele l i ( 1 9 7 8 ) examined general aspects of n u t r i t i o n a l status of male a g r i cu l t u r a l migrant workers, popularly known as b o i a - f r i a s (or "co ld meal eaters" ) res id ing in the Ribeirao Preto area. It was found that adult male energy intakes averaged 2 , 2 0 0 kcal per day and that most ind iv idua l s followed a s im i l a r meal pat tern : no breakfast ; r i ce and beans for lunch; and r i ce and beans for supper occas iona l l y supplemented with eggs, beef, tomatoes, or sausage.. J8% of subjects showed evidence of p a r a s i t i c i n - f e s t a t i o n , and hl% of subjects exhib i ted anthropometric indices of f i r s t grade malnutr i t ion according to the Gomez ( 1 9 5 6 ) c l a s s i f i c a t i o n , using American standards for comparison. Biochemical tests were a l so conducted in A n g e l e l i ' s ( 1 9 7 8 ) study. Over 9 0 % of subjects had normal values for plasma vitamin A and carotene; 8 7 % had normal values for hemoglobin; and 5 7 % had norma.l values for hematocrit. Protein and albumin in the serum were normal in most subjects . A recent comprehensive n u t r i t i o n survey of 1 0 0 b o i a - f r i a migrant worker fami l ies was conducted in Ribeirao Preto by Desai and co-workers ( I 9 8 O ) . A socio-economic quest ionnaire used in th is study y ie lded the fo l lowing informat ion: male family members usual ly worked as day labourers cut t ing sugar cane or p ick ing cof fee on large land holdings near the c i t y ; women and ch i ld ren often worked as well to supplement the family income; most fami l ie s reported earning subs tan t i a l l y less than the legal minimum wage; and 40-60% of adult b o i a - f r i a s had no education whatsoever. There was no sewage system in most homes and p a r a s i t i c i n fe s ta t i on was found in 36 60% of ch i l d ren examined. The typ i ca l d ie t of b o i a - f r i a s , as revealed from food frequency quest ionnaires , is out l ined in Table 11-1. Quant i tat ive ana lys i s of the adult b o i a - f r i a d i e t , based on 24-hour reca l l interviews, showed that the average da i l y intake of most nutr ients was below the World Health Organiza- tion/Food and Ag r i cu l tu re Organization (WHO/FAO) recommended d ietary al lowances. Very low nutr ient intakes were reported for ca lc ium, r e t i n o l , thiamin, n i a c i n , r i b o f l a v i n , and ascorbic a c i d , and for iron among women only. For a l l anthropometric parameters measured, mean b o i a - f r i a values were well below American standards, except for weight in female adu l t s . In terms of biochemical analyses, 25% of the adult population examined showed low serum vitamin A values, 30% showed low or d e f i c i e n t serum carotene va lues, and 25% showed low values for hemoglobin and hematocrit. These resu l t s d i f f e r somewhat from A n g e l e l i ' s ( 1 978 ) . This could be due to the fact that Angelel i (1978) studied only male subjects ; whereas, Desai and co-workers (1980) studied both males and females, and found that males had higher mean values than females for plasma vitamin A and carotene, and for hemoglobin and hematocrit. In a separate report , Desai and co-workers (1980a) indicated that vitamin E status of boi a - f r i as appeared to be s a t i s f a c t o r y . TABLE 11-1 T y p i c a l d i e t o f b o i a - f r i a m i g r a n t w o r k e r s . 3 37 Meal s Foods and beverages consumed Dai l y Week 1y Somet i mes B r e a k f a s t C o f f e e & s u g a r , w h i t e bread Hot mi l k & sugar' 3 Lunch White rum, r i c e & beans Beer E g g - f r i e d S a l a d - r a w : -tomato -on i on Beef o r c h i c k e n - f r i e d S a l a d - r a w : - l e t t u c e - w i l d c h i c o r y V e g e t a b l e s - b o i l e d : - p o t a t o - c a s s a v a Di nner White rum, r i c e & beans Beer Macaron i-soup White bread S a u s a g e - f r i e d Snacks C o f f e e & s u g a r Tea & sugar S o f t d r i n k s b Limewater S sugar F r u i t s : banana, orange Fats Soybean o i l , p o r k l a r d Cond i ments S a l t , o n i o n , g a r l i c Red pepper Tomato sauce a M o d i f i e d from Desai et_ aj_. , 1 9 8 0 . b Consumed m a i n l y by c h i l d r e n . 38 CHAPTER I I I METHODS AND MATERIALS 1. P o p u l a t i o n and Sample A s t u d y was d e s i g n e d t o o b t a i n i n f o r m a t i o n on the n u t r i t i o n a l s t a t u s and p h y s i c a l work performance o f c h i l d r e n o f m i g r a n t a g r i c u l t u r a l w o r k e r s , commonly i d e n t i f i e d as b o i a - f r i a s , l i v i n g i n s o u t h e r n B r a z i l . For the purposes o f c o m p a r i s o n , i n f o r m a t i o n was a l s o o b t a i n e d on the n u t r i t i o n a l s t a t u s and p h y s i c a l work performance of c h i 1 d r e n from h i g h e r s o c i o - e c o n o m i c groups who had a c c e s s t o adequate d i e t s and h e a l t h c a r e . In the s t u d y , t h e s e l a t t e r c h i l d r e n were i d e n t i f i e d as " w e l l - t o - d o " and s e r v e d as c o n t r o l s . The o b j e c t i v e s o f the st u d y were t o compare b o i a - f r i a c h i l d r e n w i t h t h e i r w e l l - t o - d o c o u n t e r p a r t s i n terms o f n u t r i t i o n a l s t a t u s and p h y s i c a l work p e r f o r m a n c e , and t o d e t e r m i n e whether parameters o f p h y s i - c a l "work performance were r e l a t e d t o parameters o f n u t r i t i o n a l s t a t u s . The s t u d y was co n d u c t e d d u r i n g the months o f May t h r o u g h A u g u s t , 1979. The s u b j e c t s o f the s t u d y were boys aged 11-14 y e a r s l i v i n g i n R i b e i r a o P r e t o i n the s t a t e o f Sao P a u l o , B r a z i l , whose p a r e n t s were e i t h e r m i g r a n t a g r i c u l t u r a l w o r k e r s , o r wel1-to-do p r o f e s s i o n a l s and businesspeop1e. S e v e r a l f a c t o r s were c o n s i d e r e d i n s e l e c t i n g s u b j e c t s f o r the s t u d y . F i r s t , o n l y male c h i l d r e n were s t u d i e d due t o time c o n s t r a i n t s . Second, the age range o f 11-14 y e a r s was chosen because t h i s i s a c r i t i c a l growth p e r i o d when n u t r i t i o n a l needs a r e h i g h . A l s o , many b o i a - f r i a c h i I d r e n l e a v e s c h o o l by age 15 t o become a g r i c u l t u r a l l a b o u r e r s , w h i l e w e l l - t o - d o c h i l d r e n remain i n s c h o o l . I t was thought t h a t c h i l d r e n i n a younger age range who were a l l s t i l l i n s c h o o l would be more l i k e l y 39 than o l d e r c h i l d r e n t o be s i m i l a r i n terms o f t h e i r d a i l y a c t i v i t i e s . T h i r d , the c i t y o f R i b e i r a o P r e t o was chosen t o be the l o c a t i o n f o r the stu d y because many m i g r a n t w o r k e r s l i v e d t h e r e and because e x c e l l e n t r e s e a r c h f a c i 1 i t i e s were a v a i l a b l e a t the U n i v e r s i t y o f Sao P a u l o H o s p i t a l . F i n a l l y , s u b j e c t s f o r the s t u d y had t o be s e l e c t e d from one o f two groups l i v i n g i n R i b e i r a o P r e t o : e i t h e r c h i l d r e n o f m i g r a n t w o r k e r s , or c h i l d r e n o f w e l l - t o - d o p r o f e s s i o n a l and b u s i n e s s p e o p l e . I t was d e c i d e d t o choose two s c h o o l s i n the c i t y t h a t were p o p u l a t e d m a i n l y by one o r o t h e r o f the two groups t o be s t u d i e d , and t o s e l e c t s u b j e c t s from t h e s e s c h o o l s . S c h o o l s were s e l e c t e d on the b a s i s o f p r e v i o u s s t u d i e s (Desai e t a 1. , 1980) and w i t h the h e l p o f l o c a l p e o p l e . B o i a - f r i a c h i l d r e n were s e l e c t e d from a p u b l i c s c h o o l i n V i l a R e c r e i o , a f a v e l a o r slum a r e a on the p e r i - phery o f R i b e i r a o P r e t o where most m i g r a n t w o r k e r s l i v e d . V i l a R e c r e i o was c h a r a c t e r i z e d as b e i n g one o f the p o o r e s t a r e a s o f the c i t y i n terms o f income l e v e l s , h o u s i n g , and e d u c a t i o n l e v e l s . W e l l - t o - d o c h i l d r e n were s e l e c t e d from a p r i v a t e s c h o o l i n J a r d i m R e c r e i o , a r e s i d e n t i a l a r e a o f R i b e i r a o P r e t o which was p o p u l a t e d a l m o s t e x c l u s i v e l y by p r o f e s s i o n a l s and b u s i n e s s p e o p l e . J a r d i m R e c r e i o was c o n s i d e r e d t o be one o f the most a f f l u e n t a r e a s o f the c i t y i n terms o f income, h o u s i n g , and e d u c a t i o n . A t o t a l o f Sk s u b j e c t s were t e s t e d , 59 b o i a - f r i a and 35 w e l l - t o - d o . 2. E x p e r i m e n t a l P r o c e d u r e A l l t e s t s e x c e p t b i o c h e m i c a l bloodwork were con d u c t e d a t the U n i v e r - s i t y o f Sao P a u l o H o s p i t a l i n R i b e i r a o P r e t o . B i o c h e m i c a l bloodwork was done i n l a b o r a t o r i e s o f the Department o f C l i n i c a l M e d i c i n e i n the F a c u l t y o f M e d i c i n e a t the U n i v e r s i t y o f Sao P a u l o i n R i b e i r a o P r e t o . 40 On the morning of t e s t i n g , subjects were taken to the hospita l at 8 a.m. They were f i r s t given a physical examination and an e l e c t r o c a r d i o - gram by a phys ic ian to detect any medical condit ions that might prevent p a r t i c i p a t i o n in the study. Subjects were then interviewed to obtain i n - formation about the i r d i e t . Following the interview, experimental equip- ment and procedures were explained to the subject and a f i r s t blood sample was taken. The subject then performed a work test on a : bicyc le-ergometer and a second blood sample was taken. Af ter the work te s t , subjects rested and were given refreshments. Anthropometric measurements were taken a f t e r the rest per iod. Subjects then returned to the i r schools and blood specimens were transported to the laboratory for ana ly s i s . The en t i r e procedure took each subject approximately 3 hours. 3. Assessment of Nut r i t i ona l Status a) Socio-economic Factors Socio-economic factors that may have bearing on n u t r i t i o n a l status were assessed by conversing with local people and by making v i s i t s to houses, markets, and shops to obtain q u a l i t a t i v e information about local cu l ture and home l i f e . Information about general phys ica l health of bo?a- f r i a as compared to we l l - to -do ch i ld ren was obtained from an examination conducted by a phys ic ian on each subject p r io r to experimental t e s t i ng . It was expected that th i s information might provide he lpfu l background in in terpret ing resu l t s of more d i r ec t tests of n u t r i t i o n a l s tatus. b) Dietary Analys i s Information on d ietary intake was obtained using the 24-hour reca 1 1 method. Each subject in the study was interviewed in Portuguese by a 41 B r a z i l i a n n u r s e who had been p r e v i o u s l y t r a i n e d t o do 24 -hour d i e t r e c a l l s . Foods e a t e n were r e c o r d e d by t he i n t e r v i e w e r and q u a n t i t i e s were e x p r e s s e d i n terms o f l o c a l measu re s . Any s upp lement s consumed were n o t e d . F i g u r e I I 1-1 i l l u s t r a t e s the q u e s t i o n n a i r e used i n the i n t e r v i e w . A l l f ood s r e - c o r d e d f o r each s u b j e c t were then coded f o r f o o d number, f ood group number, and q u a n t i t y . T h i s i n f o r m a t i o n was t r a n s c r i b e d o n t o computer c a r d s f o r a n a l y s i s . The m o d i f i e d f ood c o m p o s i t i o n t a b l e f o r B r a z i l i a n f ood s d e v e l o p e d by Swann (1979) was used f o r n u t r i e n t a n a l y s i s , w i t h the a d d i t i o n o f 35 new f o o d s . I n f o r m a t i o n on t he c o m p o s i t i o n o f the 35 f ood s not i n c l u d e d i n Swann ' s t a b l e was o b t a i n e d f rom Leung and F l o r e s (1961) and Watt and M e r r i l l (1963), and n u t r i e n t c o m p o s i t i o n was e x p r e s s e d pe r lOOg o f f o o d . I f a f ood was l i s t e d i n bo th s o u r c e s , the more l o c a l l y a p p l i c a b l e s o u r c e was u s e d . I f a f ood c o u l d not be found i n e i t h e r s o u r c e , the c o m p o s i t i o n o f . the food most c l o s e l y a p p r o x i m a t i n g i t was u s e d , a - t o c o p h e r o l v a l u e s f o r f ood s were o b t a i n e d f r om c o m p o s i t i o n t a b l e s d e v e l o p e d by B a u e r n f e i n d and Desai (1977). For mixed d i s h e s , B r a z i l i a n r e c i p e s were o b t a i n e d f r om l o c a l cookbooks and f rom l o c a l women. These r e c i p e s were a ve r a ged where a p p r o p r i a t e and i n g r e d i e n t s and q u a n t i t i e s o f f ood s used i n mixed d i s h e s were a p p r o x i m a t e d . The mixed d i s h was then coded i n terms o f i n d i v i d u a l i n g r e d i e n t f o o d s . Computer programmes d e v e l o p e d by s t a t i s t i c i a n s a t the U n i v e r s i t y o f B r i t i s h Co l umb i a were used f o r n u t r i e n t a n a l y s i s . N u t r i e n t i n t a k e and p e r - c e n t a g e c o n t r i b u t i o n o f f o o d g roups t o n u t r i e n t i n t a k e were d e t e r m i n e d f o r each s u b j e c t . N u t r i e n t i n t a k e s were compared t o WHO/FAO recommended d a i l y i n t a k e s (Passmore e t a l . , 1974). 42 QUANT IDADES DE COMIDAS E BEBIDAS CONSUMIDAS NO DIA ANTERIOR (ULTIMAS 24 HORAS) NOME DA FAMILIA DATA: NOME DA CRIANCA I DADE VILA RECREIO • VITA ET PAX • SEXO: HORARIO ALIMENTOS QUANT 1 DADE OBSERVAQOES Cafe da Manna Entre Cafe e Almoco ALMOqO Entre Almoco e Jantar JANTAR Noi te FIGURE I I 1-1 Questionnaire used in 24-hour d ie t reca l l interviews. 43 c) Anthropometric Deterrhi nat i ons A l l anthropometric measurements were taken according to standard recommended procedures ( J e l l i f f e , 1966). The fo l lowing parameters were measured: weight, standing height, mid-upper-arm circumference, and t r iceps sk in fo ld thickness. In add i t i on , mid-upper-arm muscle c ircum- ference was c a l c u l a t e d . To measure weight, a platform beam balance was used. Subjects were weighed to the nearest 1/10 kg before meals, without shoes, and wearing a minimum of l i gh t c l o th ing . No cor rec t ion was made for c l o th ing . Standing height was measured using a platform beam balance equipped with a v e r t i c a l measuring rod. Subjects were measured to the nearest mm without shoes. Mid-upper-arm circumference was measured using a p l a s t i c i z e d f i b r e tape. Measurements were taken to the nearest mm on the f u l l y relaxed l e f t arm. Tr iceps sk in fo ld thickness was measured using Lange sk in fo ld ca l i pe r s which exerted a uniform pressure of 10 g/mm2. Measurements were taken to the nearest 1/10 mm on the f u l l y relaxed l e f t arm. Mid-upper-arm muscle circumference was ca lcu la ted for each subject using the fo l lowing formula ( J e l1 i f f e , 1966) : xi = x 2 = T T ( X 3 ) where: x^ = mid-upper-arm-muscle circumference (cm) X£ = mid-upper-arm circumference (cm) X3 = t r i ceps sk in fo ld thickness (cm) A l l anthropometric measurements were compared to both internat iona l standards (Nelson et^ aj_. , 1979 and Fr isancho, 1974) and B r a z i l i a n stan- dards (Marcondes et a l . , 1971) where poss ib le . d) B i o c h e m i c a l T e s t s S u b j e c t s were asked t o g i v e b l o o d b e f o r e and a f t e r e x e r c i s e t e s t s . B e f o r e e x e r c i s e , a p p r o x i m a t e l y 10 ml o f venous b l o o d were drawn u s i n g s t e r i l i z e d d i s p o s a b l e n e e d l e s and r u b b e r - s t o p p e r e d g l a s s v a c u t a i n e r tubes Of the 10 m l , a p p r o x i m a t e l y k ml were drawn i n t o a tube c o n t a i n i n g the a n t i - c o a g u l a n t e t h y l e n e - d i a m i n e t e t r a a c e t i c a c i d (EDTA), f o r t e s t r e q u i r - i n g whole b l o o d , and a p p r o x i m a t e l y 6 ml were drawn i n t o a tube c o n t a i n i n g no a n t i - c o a g u l a n t , f o r t e s t s r e q u i r i n g serum. A f t e r e x e r c i s e , a n o t h e r h ml o f b l o o d were drawn i n t o a tube c o n t a i n i n g EDTA. Blood samples were r e - f r i g e r a t e d and a n a l y s e d w i t h i n 2k-k8 hours f o r the f o l l o w i n g : t o t a l hemo- g l o b i n , h e m a t o c r i t , serum i r o n , t o t a l serum i r o n - b i n d i n g c a p a c i t y , serum t o t a l p r o t e i n , and serum a l b u m i n . The p e r c e n t a g e o f t r a n s f e r r i n s a t u r a - t i o n i n serum was a l s o c a l c u l a t e d . T o t a l hemoglobin was d e t e r m i n e d u s i n g the cyanomethemog1obin c o l o r i - m e t r i c method (Crosby and Ho u c h i n , 1957; D r a b k i n , 19^9; and E i l e r s , 1967)• For each sample, 20 y l o f whole b l o o d were added t o 5-0 ml o f D r a b k i n ' s s o l u t i o n (100 p a r t s sodium b i c a r b o n a t e , 20 p a r t s p o t a s s i u m f e r r i c y a n i d e , and 5 p a r t s p o t a s s i u m c y a n i d e i n 1,000 ml o f water w i t h 0.5 ml o f B r i j - 3 5 s o l u t i o n , 30 g/100 ml, added). A f t e r b e i n g mixed w e l l and s t a n d i n g f o r 15 m i n u t e s , sample a b s o r b a n c e s were read a t 5^0 nm on a Beckman DU s p e c t r o p h o t o m e t e r . S t a n d a r d s were p r e p a r e d a c c o r d i n g t o the s p e c i f i c a t i o n s o f E i l e r s (1967) and t o t a l hemoglobin i n each sample'was d e t e r m i n e d from a c a l i b r a t i o n c u r v e . H e m a t o c r i t was d e t e r m i n e d u s i n g the ICNND s t a n d a r d method (1963 ) - For each sample, a s m a l l amount o f whole b l o o d was i n t r o d u c e d i n t o a m i c r o - c a p i l l a r y t u b e , w h i c h was then s e a l e d a t one end w i t h C r i t o s e a l p u t t y , and c e n t r i f u g e d a t 3,000 rpm f o r 5 m i n u t e s . When the c e l l s were packed, the percentage of volume that was red blood c e l l s was determined using a standard m i c ro - cap i l l a r y hematocrit reader. Serum iron and tota l serum i ron-b inding capacity were determined using fe r roz ine co l o r imet r i c methods (Carter, 1971 :and Per s i jn et_ a_l_. , 1971)- To determine serum i ron , 0.5 ml of serum was added to 2.5 ml of buffer s o lu - t ion (hydroxylamine hydrochlor ide 1.5% w/v in acetate bu f fe r , pH 4.5), and i n i t i a l absorbance was read at 560 nm on a Beckman DU spectrophoto- meter. Then 0.05 ml of fe r roz ine (0.85% w/v in hydroxylamine hydro- ch lo r ide so lut ion) was added and the so lu t ion was incubated at 37° for 10 minutes. F inal absorbance was then read at 560 nm. A standard was prepared and the fo l lowing formula was used to ca l cu l a te serum tota l i ron: Serum tota l iron (pg/lOOm) = Final A t e s t ~ 1 n ' t ' a 1 A t e s t -= - : — 7 : — r — : — - — 7 x Concentration . , .(yg/lOO ml) Final A ^ , ,-Initial A ^ , , standard 3 standard standard Where: A^ ^ = absorbance at 560 nm of te s t , test A ^ , , = absorbance of 560 nm of standard, standard To determine to ta l serum i ron-b inding capac i ty , 0.5 ml of serum was added to 0.5 ml of iron standard so lu t ion which contained 500 yg/100 ml of i ron, and i n i t i a l absorbance was read at 560 nm. Then 0.05 ml of fe r roz ine was added and the so lut ion was incubated at 37° for 10 minutes F ina l absorbance was read at 560 nm. A standard was prepared and the fol lowing formulae were used to ca l cu l a te tota l i ron-b inding capac i ty : 50 1. Serum unsaturated i ron-b inding capacity = Concentration , .(uq/lOO ml) - s tandard 3 Fi na I A - i nt t i a I A test test Final A , - I n i t i a l A . standard standard x Concentration .(tig/100 ml) standard 3 where: = absorbance at 560 nm of test test A ^ , . = absorbance at 560 nm of standard standard 2. Serum tota l i ron-b inding capacity (yg/100 ml) = Serum total iron (ug/100 ml) + Serum unsaturated iron-binding capacity (yg/100 ml) Percentage of t r a n s f e r r i n saturated was ca lcu la ted using the fo l lowing formula: L ̂  c .. Serum total iron (yg/100 ml) % transferrin saturation = 7 .—: ',. r — , ,A x 100 Serum total iron-binding capacity (yg/100 ml) Serum tota l prote in was determined using the b iuret co l o r imet r i c method (Gornall et_ a_l_., 1949). For each sample, 0.1 ml df serum was added to 5.0 ml of b iuret reagent (0.15% w/v copper su l f a te in 3-0% w/v sodium hydroxide). The so lu t ion was mixed w e l l , allowed to stand at room temperature for 15 minutes, then absorbance was read at 540 nm on a Beckman DU spectrophotometer. A standard was prepared and serum tota l prote in was ca lcu la ted using the fo l lowing formula: Serum tota l prote in (g/100 ml) = Absorbance/ri, n\ of test - r r r ~E J — T * Concentration ^ , , (g/100 ml) Absorbance(c^g) °' standard standard Serum albumin was determined using the bromcresol green co l o r imet r i c method (Doumas and Biggs, 1972 and Rodkey, 19&5). 20 yl of serum were added to 5.0 ml of bromcresol green so lut ion (0.01% w/v in buf fer , pH 4.0), and 51 the sample was mixed w e l l . A f t e r s t a n d i n g f o r 10 minutes a t room tempera- t u r e , the a b s o r b a n c e o f t h e sample was rea d a t 630 nm on a Beckman DU s p e c t r o p h o t o m e t e r . A s t a n d a r d was p r e p a r e d and serum a l b u m i n was c a l c u - l a t e d u s i n g the f o l l o w i n g f o r m u l a : Serum a l b u m i n (g/100 ml) = A b s o r b a n c e , 6 3 Q v -TT r x C o n c e n t r a t i o n ^ , ,(g/100 ml) Absorbance/ \ , , s t a n d a r d (630) s t a n d a r d For a l l b i o c h e m i c a l d e t e r m i n a t i o n s , s u b j e c t s ' v a l u e s were compared t o normal v a l u e s ( S a u b e r l i c h e t a 1., 1974). k. Assessment o f P h y s i c a l Work Performance Two t e s t s were used t o a s s e s s p h y s i c a l work p e r f o r m a n c e : change i n h e a r t r a t e i n r e s p o n s e t o work, and change i n b l o o d l a c t i c a c i d i n res p o n s e t o work. To a s s e s s the change i n h e a r t r a t e i n response t o work, the f o l l o w i n g p r o c e d u r e was used. F i r s t , each s u b j e c t was c o n n e c t e d t o a c o n t i n u o u s h e a r t r a t e m o n i t o r u s i n g e l e c t r o d e s which were taped t o h i s c h e s t . The sub- j e c t then was s e a t e d on a b i e y e 1e-ergometer ( B r a z i l i a n - m a d e Funbec model) and f o l l o w i n g a 3 m i n u t e r e s t p e r i o d , commenced p e d a l l i n g . S u b j e c t s p e d a l l e d f o r 3 minutes w i t h a l o a d o f 25 w a t t s , 3 minutes w i t h a l o a d o f 50 w a t t s , and 3 minutes w i t h a l o a d o f 75 w a t t s . T h i s was f o l l o w e d by a n o t h e r 3 m i n u t e r e s t p e r i o d . P e d a l l i n g was thus c o n t i n u o u s f o r 9 mimutes w i t h pace h e l d c o n s t a n t a t 50 rpm. Heart r a t e was r e c o r d e d a t the end o f each minute o f t e s t i n g , i n c l u d - i n g r e s t p e r i o d s . Change i n h e a r t r a t e was c a l c u l a t e d by s u b t r a c t i n g minimum r e c o r d e d h e a r t r a t e from maximum r e c o r d e d h e a r t r a t e . I f a t any 9 52 t ime d u r i n g t e s t i n g a s u b j e c t ' s h e a r t r a t e exceeded 180 b e a t s pe r m i n u t e , t e s t i n g was s t o p p e d . A c a r d i o l o g i s t was p r e s e n t t h r o u g h o u t t he e n t i r e t e s t p e r i o d . As an i d e x o f f a t i g u e , l a c t i c a c i d i n r e spon se t o work l o ad was measured i n who le b l o o d c o l l e c t e d b e f o r e and a f t e r e x e r c i s e i n a manner p r e v i o u s l y d e s c r i b e d . Immed ia te l y a f t e r c o l l e c t i o n , 2.0 ml o f who le b l o o d were t r a n s f e r r e d i n t o 4 .0 ml o f c o l d p e r c h l o r i c a c i d (8% w/v) t o p r e c i p i - t a t e b l o o d p r o t e i n s and s t a b i l i z e l a c t i c a c i d ( Long , 1944; Marbach and W e i l , 1967; and Sega l e t a 1. , 1956 ) . T h i s s o l u t i o n was mixed v i g o r o u s l y and c e n t r i f u g e d . The r e s u l t i n g c l e a r s u p e r n a t a n t was then used t o d e t e r - mine l a c t i c a c i d by t he l a c t a t e dehydrogenase e n z y m a t i c method ( Long , 1944; Marbach and W e i l , 1967; and Sega l et^ a_l_. , 1956 ) . For each s amp le , 0.2 ml o f s u p e r n a t a n t was added t o 2.8 ml o f a s o l u t i o n c o n t a i n i n g : 10 mg o f n i c o t i n a m i d e a d e n i n e d i n u c l e o t i d e (NAD); 2.0 ml o f g l y c i n e b u f f e r , pH 9 - 2 ; 4 . 0 ml o f w a t e r ; and 0.1 ml o f l a c t a t e dehyd rogena se s u s p e n s i o n , 1,000 u n i t s / m l i n ammonium s u l f a t e . The s o l u t i o n was mixed and i n c u b a t e d a t 37° f o r 30 m i n u t e s . Then a b s o r b a n c e was read a t 340 nm on a Z e i s s s p e c t r o p h o t o m e t e r . L a c t i c a c i d i n t he sample was c a l c u l a t e d u s i n g t he f o l l o w i n g f o r m u l a : B l o o d l a c t i c a c i d (mg/100 ml) = 3.0 x 90.0 6.22 x 0.0667 x 1 A 3 4 0 X = A 3 1 F 0 X 65.1 10 Where: ^31+0 maximum a b s o r b a n c e o f sample a t 340 nm r e a c t i o n v a l u e (ml) 3.0 6.22 m i l l i m o l a r e x t i n c t i o n c o e f f i c i e n t o f NADH a t 340 nm volume o f b l o o d sample i n c u v e t (ml) 0 .0667 53 1 = 1 i ghtpath (cm) 90.0 = molecular weight of l a c t i c ac id (g/mole) 10 = conversion factor 1000 ml T ml. Change in blood l a c t i c ac id was ca lcu la ted by subtract ing l a t i c ac id before exerc i se from l a c t i c ac id a f te r exerc i se . Percentage d i f fe rence between l a c t i c a c i d before and a f te r exerc i se was a l so c a l cu l a ted . 5. S t a t i s t i c a l Analys is A l l s t a t i s t i c a l analyses were conducted using computer f a c i l i t i e s and programmes at the Univers i ty of B r i t i s h Columbia. For a l l data, b o i a - f r i a and we l l - to -do ch i l d ren were f i r s t compared as two separate groups. Studentis t - t e s t and the chi -square test were used to determine the s i g n i - f icance of d i f ferences between the two groups. Then, to determine the assoc ia t ion between nu t r i t i ona l status, and phys i -.. cal work performance, co r re l a t i on analys i s was used. Pearson's co r re l a t i on c o e f f i c i e n t s were determined for se lected pairs of va r i ab le s , t reat ing b o i a - f r i a and we l l - to -do subjects as one group. Corre la t ion c o e f f i c i e n t s were a lso determined for the same var iab les t rea t ing the two groups separ- a te l y . However, s ince these values were not found to be d i f f e r e n t than those for the two groups treated as one, they are not reported in the study. 54 CHAPTER IV RESULTS 1 . Assessment of Nut r i t i ona l Status a) Socio-economic Factors Local v i s i t s y ie lded the fo l lowing information about l i v i n g condit ions in V i l a Recreio and in Jardim Recreio.. V i l a Recreio was located approximately 10 km, or 45 minutes by bus, from the center of Ribeirao Preto. L iv ing condit ions in V i l a Recreio were general ly very poor. Most fami l ie s l i ved in two-or three-room houses that they constructed themselves with d i r t f l o o r s , wooden wal ls and t i l e or t i n roofs. Figure IV-1 is i l l u s t r a t i v e of typ ica l migrant worker hous- ing. These homes often had no e l e c t r i c a l l i gh t ing or v e n t i l a t i o n , and much of the time cooking was done outdoors on open f i r e s . Many homes did not have running water, so fami l ies shared water taps located in pub l ic l o t s . There was no sewage system in most V i l a Recreio homes, so sewage and other waste water flowed into the s t ree t s . Figure IV-2 i l l u s t r a t e s a typ ica l s t reet scene in V i l a Recreio where ch i ld ren played barefoot in the e f f l u e n t , a p rac t i ce probably aggravating chronic problems with para- s i t i c i n fec t i on that have been documented among bo i a - f r i as (Desai et a 1., 1980). So i l in the area was dry and red ( terra roxa) and red dust often coated ch i l d ren and the i r c l o th ing . Very few fami l ie s planted vegetable gardens or f r u i t t rees , but some kept domestic animals such as dogs or cat s . Most b o i a - f r i a fami l ie s did not possess the i r own cars or horses for t ransportat ion and depended on b icyc les or the municipal bus to travel to FIGURE IV-2 Typica l s t reet in V i l a Recreio. 56 the c i t y center. Bus travel was both time-consuming and cos t l y so that as a r e s u l t , most f ami l i e s bought food l o c a l l y at corner stores such as the one i l l u s t r a t e d in Figure IV—3- These stores had l imi ted stock se lec t i on with pr ices approximately 15% higher than in the larger stores in the c i t y center (Swann, 1979)- Figure WJ-k shows the type of goods ava i l ab le in a V i l a Recreio corner s tore : l i quo r , c i g a re t te s , white unenriched bread, and sausages, as well as white r i ce and dr ied kidney beans. Fresh produce was seldom so l d . Jardim Recreio was a l so located approximately 10 km from the center of Ribeirao Preto but l i v i n g condit ions in th is suburb were superior to those in V i l a Recreio. Most f ami l i e s in Jardim Recreio l i ved in a t t r a c t i v e three- or four-bedroom homes b u i l t of wood and stucco or br ick construc- t ion with t i l e f l oor s and roofs. Figures IV-5 and IV-6 i l l u s t r a t e typ ica l homes found in Jardim Recreio. A l l homes here had e l e c t r i c i t y , running water, and f lush t o i l e t s . Most fami l ie s had gas stoves and r e f r i g e r a t o r s , as well as appl icances such as washing machines, t e l e v i s i o n s , and radios. In many of these homes, b o i a - f r i a s were h ired to perform domestic duties and to do gardening chores. The s t reets in Jardim Recreio were a l l paved and most homes had fenced gardens where f r u i t , vegetables and flowers were grown. Most fami l ie s owned cars and did the i r shopping in downtown Ribeirao Preto. The se lec - t ion of foods a va i l ab l e in the c i t y markets was wide-ranging: fresh pro- duce, meats, various baked goods, and imported confect ions . People from Jardim Recreio a l so frequented the many restaurants located in Ribeirao Preto. It was es tab l i shed from conversations with local people that the average migrant worker earned approximately US$1,000 annual ly. The average FIGURE \\l-k Goods ava i l ab le in typ ica l store in V i l a Recreio (Photo courtesy of Dr. l.D. Desai) 58 FIGURE IV-6 Typica l house in Jardim Recreio. 59 w o r k i n g p e r s o n J s income i n J a r d i m R e c r e i o was e s t i m a t e d t o be a p p r o x i m a t e l y US$10,000 a n n u a l l y . Thus, t h e r e was a t e n f o l d d i f f e r e n c e i n average i n - comes i n the two a r e a s . As p r e v i o u s l y m e n t i o n e d , most p e o p l e i n V i l a R e c r e i o e a r n e d t h e i r l i v i n g p i c k i n g c o f f e e o r c u t t i n g s u g a r - c a n e on nearby f a r m s . On the o t h e r hand, most p e o p l e i n J a r d i m R e c r e i o were d o c t o r s , l a w y e r s , p r o f e s s o r s , o r b u s i n e s s e x e c u t i v e s . I n f o r m a t i o n about the h e a l t h s t a t u s o f b o i a - f r i a and w e l l - t o - d o c h i l d r e n , o b t a i n e d from p h y s i c a l e x a m i n a t i o n s , i s summarized i n T a b l e IV-1. From t h i s t a b l e i t can be seen t h a t p r o p o r t i o n a l l y fewer b o i a - f r i a than w e l l - d o - do s u b j e c t s were a p p a r e n t l y h e a l t h y , as i n d i c a t e d by a normal e l e c t r o - c a r d i o g r a m (ECG) and by the absence o f b r o n c h i a l i n f e c t i o n . More boi a - f r i a than w e l l - t o - d o s u b j e c t s had c a r d i a c i r r e g u l a r i t i e s , and more b o i a - f r i a than w e l l - t o - d o s u b j e c t s e x h i b i t e d symptoms o f i n f e c t i o n such as f e v e r , cough, o r s o r e t h r o a t . b) D i e t a r y A n a l y s i s The mean d a i l y n u t r i e n t i n t a k e o f b o i a - f r i a and w e l l - t o - d o s u b j e c t s i s shown i n T a b l e IV-2. For a l l n u t r i e n t s e x c e p t a - t o c o p h e r o l , the i n t a k e o f b o i a - f r i a s u b j e c t s was lower than t h a t o f w e l l - t o - d o s u b j e c t s . For the f o l l o w i n g n u t r i e n t s , d i f f e r e n c e s i n mean i n t a k e between b o i a - f r i a and w e l l - to-do s u b j e c t s were s t a t i s t i c a l l y s i g n i f i c a n t : e n e r g y , p r o t e i n , t o t a l f a t , c a l c i u m , i r o n , v i t a m i n A, t h i a m i n , r i b o f l a v i n , and v i t a m i n C. S t a n - d a r d d e v i a t i o n was v e r y h i g h f o r mean i n t a k e s o f c a l c i u m , v i t a m i n A, n i a c i n , and v i t a m i n C. T a b l e IV-3 shows the mean d a i l y n u t r i e n t i n t a k e o f b o i a - f r i a and " w e l l - t o - d o s u b j e c t s i n comparison w i t h WH0/FA0 recommended i n t a k e s (Passmore et_ aj_. , 1974). The mean i n t a k e o f b o i a - f r i a s u b j e c t s was l e s s TABLE IV-1 Comparison of ind icators of health status in subjects from b o i a - f r i a and we l l - to -do fami l i e s . Number of s u b j e c t s 3 Health status ind icator Boi a - f r i a (n = 58) Well - to-do (n = 34) Apparently heal thy: 35 (60.3) b 30 (88.2) . as indicated by a b r i e f physical examination and an ECG. Cardiac i r r e g u l a r i t i e s : 6 (10.3) 1 (2.9) as indicated by an abnormal ECG. Bronchial i n f e c t i o n : 17 (29.3) b 3 (8.8) as indicated by presence of fever,. cough , sore throat, or chest congestion a Figures in parentheses denote % of tota l in group. b Values for b o i a - f r i a and wel l - to -do subjects are s i g n i f i c a n t l y d i f f e r e n t (p < .001) using chi -square te s t . TABLE IV-2 Comparison of da i l y nutr ient intake of subjects from b o i a - f r i a and wel l -po-do f am i l i e s . Dai ly intake (mean + SD) Nutrient B o i a - f r i a Wel l - to-do I r T ^ W (n = 32) Energy (kcal) U75.6 + 485 .9 b 1863 .2 + 604.0 (kcal/kg) 43.4 + 18 .2 37 • 7 + 15.6 Protein (g) 51 .0 27 .o a 79. .4 + 32.8 (g/kg) 1 .49 + 0 .79 1, .61 + 0.65 Total fat (g) 60.9 + 21 • 9 b 81 , .6 + 42.1 Carbonhydrate (g) 182.7 + 66, .5 206, • 7 + 67.6 Calcium (mg) 391 .1 + 264, ,4 a 681 . 8 + 359.0 Iron (mg) 7-9 + 3. . l d 10. .0 + 4.3 Vi tami n A (RE) 451.9 + 253. , l a 1121. ,6 + 570.9 Thiamin (mg) 0.59 + 0. ,24 d 0. 76 + 0.40 Ribof lav in (mg) 0.78 + 0. ,38 a 1 . 27 + 0.46 Niacin (mg) 8.55 + 7. ,14 12. 04 + 1 1.89 Vitamin C (mg) 28.7 + 42. ,6 a 95. 0 + 85.8 ot-Tocopherol equivalents (mg)^ 4.65 + 1. 85 4. 34 + 1 -99 a - c Values for b o i a - f r i a and we l l - to -do subjects are s i g n i f i c a n t l y d i f f e r e n t using Student 's one - t a i l ed t - t e s t : a p < .001 b p < .01 c p < .05 d a-Tocopherol equivalent value obtained by mul t ip ly ing mg a-tocopherol x 1.2 to cor rect for non-atocopherols (Desai et a l . 1980a). TABLE IV-3 D a i l y n u t r i e n t i n t a k e o f s u b j e c t s f rom b o i a - f r i a and w e l l - t o - d o f a m i l i e s i n c o m p a r i s o n w i t h WHO/FAO recommended d a i l y i n t a k e s . WHO/FAO Mean d a i l y i n t a k e e x p r e s s e d as N u t r i e n t Recommended % o f WHO/FAO recommended d a i l y i n t a k e Boi a - f r i a W e l l - t o - d o Energy 2600 k c a l 56.8 C 71.7 71 k c a l / k g 61 . l c 5 3 . l c P r o t e i n 37 - 43 g b 118.6 214.6 1.0-1.2 g / k g b 129.6 159.4 Ca 1 c i urn 600 - 700 mg 60.2 C 104.9 1 ron r- -7 b 5 - 7 mg 112.9 200.0 Vi tami n A 575 RE 78.6 195.1 Th i ami n 1 .0 mg 59.0 C 76.0 Ri b o f1a v i n 1 .6 mg 48.8 C 79.4 N i ac i n 17.2 mg 49.7 C 70.0 Vi tami n C 20 mg 143.5 475.0 a Passmore e_t aj_. , 1974. b Lower v a l u e a p p l i e s t o d i e t r i c h i n a n i m a l s o u r c e f ood s ( w e l l - t o - d o ) . H i g h e r v a l u e a p p l i e s t o mixed ce rea1 -1egume d i e t w i t h s m a l l amounts o f a n i m a l s o u r c e foods ( b o i a - f r i a ) . c V a l u e s a r e l e s s than 2/3 WHO/FAO recommended v a l u e s . 63 than 2/3 of that recommended for the fo l lowing nu t r ien t s : energy, calc ium, thiamin, r i b o f l a v i n , and n i a c i n . In contras t , the mean intake of w e l l - t o - do subjects was greater than 2/3 of the recommended intake for a l l nutr ients except energy intake per unit of body weight. The mean intakes of p ro te i n , i r on , and vitamin C were over 100% of the recommended intake for both boi a - f r i a and we l l - to -do subjects . Table IV-4 shows the actual number of subjects in each group who had da i l y nutr ient intakes that were below 2/3 of the leve ls recommended by the WH0/FA0. As th i s table i l l u s t r a t e s , between 60 and 80% of b o i a - f r i a sub- jec t s had da i l y intakes below 2/3 of those recommended for the fo l lowing nu t r ien t s : energy, calc ium, thiamin, r i b o f l a v i n , n i a c i n , and vitamin C. In genera l , fewer we l l - to -do subjects than b o i a - f r i a subjects had nutr ient intakes that were below 2/3 of the recommended leve l s . These d i f ferences between b o i a - f r i a and we l l - to -do subjects were s t a t i s t i c a l l y s i g n i f i c a n t for the fo l lowing nu t r i en t s : energy, ca lc ium, thiamin, r i b o f l a v i n , n i a c i n , and vi tami n C. The percentage contr ibut ion of various food groups to nutr ient intake is i l l u s t r a t e d in Table IV-5. In b o i a - f r i a d i e t s , most energy was suppl ied by cereals (40.0%) and legumes (24.4%). Comparatively, most energy was suppl ied by animal prote in sources (25.2%), cereals (18.9%), and sweets (15-4%) in we l l - to -do d i e t s . Protein in the b o i a - f r i a d ie t was derived from animal sources (34.0%), legumes (25.2%), and cerea ls (23-8%); whereas, in the we l l - to -do d i e t , prote in was derived mainly from animal sources (57-8%). In both groups, dairy products suppl ied approximately one ha l f of the calcium in the d i e t . In the b o i a - f r i a d i e t , 48.8% of iron came from legumes and 18.2% from the animal prote in sources; whereas, in the w e l l - t o - TABLE IV-4 Number o f s u b j e c t s w i t h d a i l y n u t r i e n t i n t a k e l e s s 2/3 o f recommended d a i l y i n t a k e . Number o f s u b j e c t s 3 N u t r i e n t B o i a - f r i a Wel1-to-do Energy 30 (71.4) b 15 (46.9) P r o t e i n 7 (16.7) 0 - Ca1c i urn 29 (69.0) b 8 (25.0) 1 ron 8 (19.0) 2 ( 6.3) Vi tami n A 10 (23.8) 1 ( 3.1) Th i ami n 30 (71.4) b 14 (43.8) Ri b o f 1 a v i n 31 (73.8) b 9 (28.1) N i a c i n 34 (81.0) C 20 (62.5) V i t a m i n C 26 (6l.9) b 8 (25.0) a F i g u r e s i n pa r e n t h e s e s denote % o f t o t a l i n group. b - c Va l u e s f o r d i f f e r e n t boi a- us i ng - f r i a and w e l l - t o - d o s u b j e c t s c h i - s q u a r e t e s t : a r e s i gni f i c a n t l y b p < .001 c p < .05 TABLE IV-5 Contribution of food groups to nutrient intake' Food groups Nutrient Dairy Animal . Cereal , F Sugars, Miscellaneous Products p r o t e i n L e g u m e S " V e 9 e t a b l « F r u , t o i l s sweets foods sources products Energy b 6. 2 12. .6 2lt. .It 2, ,2 1.9 ItO. ,0 5. .0 7. .5 0.2 c 13. 2 25. .2 12. 0 3. .It 5.8 18, 9 5. .2 15. .It 0.8 Prote i n b 12. .9 3<t. .0 25. 2 2, .0 1.0 23. ,8 0. .8 0. .0 0.1 c 16. 9 57. ,8 10. 5 1 , 9 1.2 9. 9 0. .5 0. .5 0.7 Total fat b 7. .8 15. 3 36. 3 1. 3 1.0 25. .9 12 .It 0 .0 0.0 c . 1 32. .2 16. 5 2. ,8 0.9 11, .9 13 .9 2. .6 0.0 Carbohydrate b U. 9 0. .1) 17. 1 3. . 1 33 55. 3 0. . 1 15 3 0̂ 5 c 9. .7 1. ,0 9. 1 It. .8 12.5 29. .0 0. 3 32. . 1 1 .It Calcium b Ii6. 6 12. 6 16. .it 1. ,6 3-7 16. . 1 0. .6 1. .0 l.lt c SI. .5 17. .6 5. 9 2. 3 5.5 7. ,5 0. .5 3. ,0 0.2 1 ron b 5. • 9 18. .2 W. .8 It. 3 it.O lit. .7 0 • 7 - 1 .3 2.0 c 8. 5 35. .8 22. .0 5. .7 12.8 10, .0 0. .7 3 • 9 0.6 Vi tami n A b 20. .it 17. .5 IU. 2 lit. .It 8.3 1, .2 13 .7 0. 5 0.0 c 32. 2 15. . 1 5. 3 18. .2 lit. 1 3 .8 6 .5 It. .8 0.0 Thiami n b 9. .6 12. .7 <!7. .2 5. .8 5.7 16, .it 0 .8 0. .it 1 .It c 12. .5 28. .it 20. 1 8. .0 13-6 11. .it 0. .7 It. .7 0.6 Ri boflav i n b 32. 8 30. 3 18. 6 2. 9 2.7 9, ,0 1. .1 0. • S 2.0 c 32. • 9 kl. 3 6. 3 3. .8 it. 7 it. .8 0. .5 It. 5 0.2 N i ac i n b 2. 5 30. 1 18. 0 7. . 1 2.8 30. .2 0. .9 . 0. .0 8.3 c 3. 3 53. .7 8. .It 8. 9 7.2 lit. .0 0. 9 0. 7 2.9 Vi tami n C b •21) .6 0 .0 0 .0 33 .5 28.5 0 .0 0 3 It .8 1.2 c 9 .2 0. .0 0 .0 27 .2 <t9-9 2 .2 0 .6 10 .0 0. 7 a-Tocopherol b 0. 3 8. .7 Itl. , I 2 • 7 2.3 32 .It 12 .5 0 .0 0.0 equ ivaIents c 7. .2 19 .5 23. .5 .5. .6 3.8 17 .7 21 .0 1 .6 0.0 a Values are percentage food group contributes to nutrient intake, b Bo i a - f r i a d ie t , c ' We I I - to-do d iet . 66 do d i e t , 22 .0% o f i r o n came f rom legumes and 35.8% f r om an ima l p r o t e i n s o u r c e s . V i t a m i n A i n b o i a - f r i a d i e t s was d e r i v e d f rom legumes ( 2 4 . 2 % ) , d a i r y p r o d u c t s ( 2 0 . 4 % ) , and a n i m a l p r o t e i n s o u r c e s ( 1 7 - 5 % ) . In w e l l - t o - d o d i e t s , v i t a m i n A came f r om d a i r y p r o d u c t s ( 3 2 . 2 % ) , v e g e t a b l e s ( 1 8 . 2 % ) , and a n i m a l p r o t e i n s o u r c e s ( 1 5 . 1 % ) . T h i a m i n was s u p p l i e d p r i m a r i l y by legumes (47.2%) and c e r e a l s (16.4%) i n b o i a - f r i a d i e t s , but by a n i m a l s p r o t e i n s o u r c e s ( 2 8 . 4 % ) , legumes ( 2 0 . 1 % ) , and f r u i t (13-6%) i n w e l l - t o - d o d i e t s . Both g roups o b t a i n e d most r i b o f l a v i n f rom d a i r y p r o d u c t s and f rom a n i m a l p r o t e i n s o u r c e s . B o i a - f r i a s u b j e c t s o b t a i n e d n i a c i n f r om c e r e a l s (30.2%) and a n i m a l p r o t e i n s o u r c e s ( 3 0 . 1 % ) ; w h e r e a s , w e l l - t o - d o s u b j e c t s o b t a i n e d n i a c i n m a i n l y f r om a n i m a l p r o t e i n s o u r c e s ( 5 3 - 7 % ) . V i t a m i n C was o b t a i n e d f r om v e g e t a b l e s ( 3 3 - 5 % ) , f r u i t ( 2 8 . 5 % ) , and d a i r y p r o d u c t s (24.6%) i n b o i a - f r i a d i e t s , bu t m a i n l y f r o m f r u i t (49 - 9% ) and v e g e t a b l e s (27-2%) i n w e l l - t o - d o d i e t s . F i n a l l y , t o c o p h e r o l s came f rom legumes (41 . 4% ) and c e r e a l s (32.4%) i n b o i a - f r i a d i e t s , but f r om legumes ( 2 3 - 5 % ) , f a t s and o i l s ( 2 1 . 0 % ) , and a n i m a l p r o t e i n s o u r c e s (19-5%) i n w e l l - t o - d o d i e t s . T a b l e s IV-6 and IV-7 show randomly s e l e c t e d but r e p r e s e n t a t i v e d a i l y menus f o r b o i a - f r i a and w e l l - t o - d o s u b j e c t s . The bo i a - f r i a d i e t was g e n e r a l l y q u i t e monotonous . B r e a k f a s t u s u a l l y c o n s i s t e d o f w h i t e b r ead w i t h c o f f e e o r m i l k , w h i l e l unch and suppe r u s u a l l y c o n s i s t e d o f r i c e and beans s upp l emen ted o c c a s i o n a l l y w i t h meat , e gg s , o r v e g e t a b l e s . Not many f ood s were e a t e n between m e a l s , bu t t ho se r e p o r t e d i n c l u d e d b r e a d , i c e c r e a m , and s o f t d r i n k s . In c o n t r a s t , d i e t s o f w e l l - t o - d o c h i l d r e n showed g r e a t e r v a r i e t y . Fo r b r e a k f a s t , t hey u s u a l l y had w h i t e b r ead w i t h m i l k and c o f f e e . Lunch u s u a l l y c o n s i s t e d o f r i c e and beans p l u s meat, f r e - q u e n t l y bee f but somet imes c h i c k e n o r s e a f o o d , g reen v e g e t a b l e s , and f r u i t TABLE IV-6 Sample d a i l y menus taken from d i e t r e c a l l s c o l l e c t e d from boi a - f r i a s u b j e c t s 3 . B r e a k f a s t 1 s l i c e w h i t e bread w i t h marga r i ne, 1 cup hot m i l k w i t h s u g a r . 2 s l i c e s w h i t e bread w i t h w i t h m a r g a r i n e , 1 cup c o f f e w i t h m i l k and s u g a r . Lunch 1 cup wh i t e r i c e , 3/4 cup k i d n e y beans, 2 f r i e d c h i c k e n wings. 3/4 cup w h i t e r i c e , 3/4 cup k i d n e y beans. A f t e r n o o n snack Supper 1 cup w h i t e r i c e , 3/4 cup k i d n e y beans, 1 t a n g e r i n e , 2 s l i c e s w h i t e bread w i t h m a r g a r i ne. 1 cup wh i t e r i ce, 3/4 cup k i d n e y beans, .1/2 cup f r i e d p o t a t o e s . a Q u a n t i t i e s a r e a p p r o x i m a t e . 68 TABLE IV-7 Sample da i l y menus taken from d iet r e c a l l s from we l l - to -do s u b j e c t s 3 . Breakfast 2 white r o l l s with but ter , 3 s l i c e s white bread with 3/4 cup cof fee with milk but ter , and sugar. 1 cup coffee with milk and suga r. Morning snack 4 p la in cookies. Lunch 1 cup wh i te r i c e , 1 cup white r i c e , 3/4 cup kidney beans, 3/4 cup kidney beans, 4 oz beef steak, 6 oz beef steak, le t tuce salad with lettuce salad with tomatoes tomatoes and oi1 and oi1 dress i ng, dress i ng, 1 cup f r i e d potatoes, 1 tanger ine, 2 cups orange j u i c e . 1 cup orange j u i c e with sugar. Afternoon snack 1 apple, 2 s l i c e s white bread with 1 tangerine. but ter . Supper 1 cup white r i c e , 1 ham and cheese sandwich 3/4 cup kidney beans, on white bread with butter 1/2 cup f r i e d cassava, 1 cup cof fee with milk and let tuce salad wi th sugar, tomatoes and o i l 2 cups cola pop. dress ing. Evening snack 1 1/2 cups orange pop. 1 cup hot milk with sugar. a Quant i t ies are approximate. 69 or j u i c e . Supper was e i the r s im i l a r to lunch or was a l i gh ter meal of sand- wiches arid co f fee . Many we l l - to -do subjects reported eat ing foods between meals such as cake, cookies, f r u i t , sof t dr inks , bread, mi lk, or candies. Most subjects , both we l l - to -do and b o i a - f r i a , reported eating three meals a day although breakfast was seldom very large. c) Anthropometric Determination A comparison of physical growth and development of subjects from boi a - f r i a and we l l - to -do fami l ie s is shown in Table IV-8. For a l l parameters measured, boi a - f r i a subjects had s i g n i f i c a n t l y lower values than w e l l - t o - do subjects . In add i t i on , b o i a - f r i a subjects had s i g n i f i c a n t l y lower values than we l l - to -do subjects for several ca l cu la ted parameters inc luding mid-upper-arm muscle c ircumference, weight for height r a t i o s , and weight and height for age. Anthropometric measurements were compared to American standards (Nelson e_t a_l_. , 1979, and Fr isancho, 1974) and to B r a z i l i a n standards (Marcondes et a 1., 1971) where pos s ib le . Weight of b o i a - f r i a and w e l l - t o - do subjects in comparison with standards is shown in Figure IV-7 - Boi a - f r i a subjects ' mean weight was 82.7% of the Amercian standard, but 100.4% of the B r a z i l i a n standard. Wel l - to-do subjects ' mean weight exceeded the American and B r a z i l i a n standards by 20.2% and 50.6% re spect i ve ly . Figure IV-8 shows height of b o i a - f r i a and we l l - to -do subjects in comparison with standards. B o i a - f r i a subjects mean height was 93-6% of the American standard, but 101.4% of the B r a z i l i a n standard. Wel l - to-do subjects ' mean height was 102.0% of the American standard and 110.5% of the B raz i l i an standard. Figure IV-9 shows t r iceps sk in fo ld th ickness, arm circumference, and 70 TABLE IV-8 Comparison o f p h y s i c a l growth and development o f s u b j e c t s from b o i a - f r i a and w e l l - t o - d o f a m i l i e s . Mean + SD Parameter Boi a- (n = - f r i a 59) Wei 1 (n = -to-do = 35) Age ( y e a r s ) 12.1 ± 1 .0 12.4 + 0.9 Weight (kg) 34.0 ± 5 • 3 3 49.4 + 10.8 H e i g h t (cm) 141.7 ± 7 • 7 a 154.5 + 8.7 Arm c i r c u m f e r e n c e (cm) 20.0 ± 2 . 6 a 23-9 + 3.1 T r i c e p s s k i n f o l d t h i c k n e s s (mm) 6.3 ± 1 • 7 a 11.1 + 4.0 Arm muscle c i r c u m f e r e n c e 2 2 W e i g h t / h e i g h t (kg/cm ) (cm) 17-9 1.7(10" 3) ± 2 + . 6 a .000 a 2. 20.5 K i o " 3 ) + + 2.6 .000 W e i g h t / h e i g h t (kg/cm) .24 + • 03 a .32 + .06 H e i g h t / a g e (cm/years) 11.8 ± 0 . 8 a 12.5 + 0.7 Weight/age ( k g / y e a r s ) 2.8 ± 0 .4 a 4.0 + 0.9 a V a l u e s f o r boi a - f r i a and w e l l - t o - d o s u b j e c t s a r e s i g n i f i c a n t l y d i f f e r e n t (p < .001) u s i n g S t u d e n t ' s o n e - t a i l e d t - t e s t . 71 AMERICAN BRAZILIAN STANDARD 3 STANDARD13 FIGURE IV-7 Weight o f s u b j e c t s from b o i a - f r i a and w e l l - t o - d o f a m i l i e s i n comparison w i t h s t a n d a r d s . a Nelson et. aj_. , 1979 . (100.0% = 41.1 k g ) , b Marcondes et. aj_. , 1971 (100.0% = 32.8 k g . ) . 72 ZD < > Q < Q < r- t/5 UJ < o IkO 120J 100J [ | St a n d a r d Boi a - f r i a Wel1-to-do ^ 90% o f s t a n d a r d AMERICAN STANDARD£ BRAZILIAN STANDARD^ FIGURE IV-8 H e i g h t o f s u b j e c t s from b o i a - f r i a and w e l l - t o - d o f a m i l i e s i n c o m p a r i s o n w i t h s t a n d a r d s . a N e l s o n et_ aj_. , 1979 (100.0% = 151 .h cm) . b Marcondes et^ aj_. , 1971 (100.0%= 139.8cm). 73 | | S t a n d a r d TRICEPS ARM ARM MUSCLE SKINFOLD CIRCUMFERENCE 0 CIRCUMFERENCE THICKNESS FIGURE IV-9 S k i n f o l d t h i c k n e s s , arm c i r c u m f e r e n c e , and arm m u s c l e c i r c u m f e r e n c e o f s u b j e c t s f rom b o i a - f r i a and w e l l - t o - d o f a m i l i e s i n c o m p a r i s o n w i t h s t a n d a r d v a l u e s . a F r i s a n c h o , 197^. b 100.0% =11.0 mm. c 100.0% = 21.6 cm. d 100.0% = 18.1 cm. 74 arm muscle circumference in comparison with American standards. Bo i a - f r i a subject s ' mean measured values were as fo l lows: 57-3% of standard for t r i ceps sk in fo ld th ickness ; 92.6% of standard for arm circumference; and 98.9% of standard for arm muscle circumference. Wel l - to-do subjects ' mean measured values, by comparison, were as fo l lows: 100.9% of standard for t r i ceps sk in fo ld th ickness; 110.6% of standard for arm circumference; and 113-3% of standard for arm muscle c ircumference. d) Biochemical Tests Results of biochemical blood tests are shown in Table IV-9. There were s i g n i f i c a n t d i f ferences between b o i a - f r i a and we l l - to -do subjects in values obtained for hematocrit, hemoglobin, and serum tota l p ro te in . The values obtained for other biochemical parameters measured were not s i g n i f i c a n t l y d i f f e r e n t for b o i a - f r i a and we l l - to -do subjects . The standard dev ia t ion was very high in values obtained for serum i ron . Table IV-10 shows b o i a - f r i a and we l l - to -do subjects ' mean values for biochemical para- meters in comparison with normal values (Sauberl ich et^ aj_., 1974). A l l measured mean values exceeded 100.0% of the normal values in a l l subjects , with the exception of hematocrit in b o i a - f r i a subjects , which was 96.8% of the normal va lue. Table IV-11 expresses the actual number of subjects in each group having biochemical parameters below normal. Among b o i a - f r i a subjects , 57-9% had hematocrit values below normal, 40.0% had serum iron values below normal, and 47.1% had t r a n s f e r r i n saturat ion below normal. Com- pa ra t i ve l y , among we l l - to -do subjects , 32.3%, 30.0%, and 27.6% had values below normal for hematocrit , serum i ron , and t r a n s f e r r i n sa tura t ion , re spec t i ve ly . D i f ferences between b o i a - f r i a and we l l - to -do subjects were 75 TABLE IV -9 Comparison o f b l o o d b i o c h e m i s t r y i n s u b j e c t s from bo i a-f r i a and w e l 1 - t o -•do f ami 1 i es , Parameter Mean ± SD a Boi a-• f r i a Wel 1 to-do H e m a t o c r i t {%) 39. • 3 ± 5 .0 (38 ) b 42, .0 + 2 . 9 ( 30 Hemoglobin (g/100 ml) 15. .3 ± 1.2(38) b 16, .4 + 1.8(31) Serum i r o n (yg/100 ml) 80. .5 ± 56.4(35) 82, .8 + 33-7(30) TIBC (yg/100 ml) 313. . 1 ± 78.4(34) 314, .4 + 56.5(29) T r a n s f e r r i n s a t u r a t i o n (%) 25. . 1 ± 13.0(34) 26, .4 + 10.7(29) Serum t o t a l p r o t e i n (g/100 ml) 7. .57 ± 0 .65 (33 ) b 7, .12 + 0.53(30) Serum a l b u m i n (g/100 m 1) 4, .64 ± 0.46(34) 4, .42 + 0.67(30) a F i g u r e s i n p a r e n t h e s e s denote number o f s u b j e c t s . b V a l u e s f o r b o i a - f r i a and w e l l - t o - d o s u b j e c t s a r e s i g n i f i c a n t l y d i f f e r e n t (p < .01) u s i n g S t u d e n t ' s t w o - t a i l e d t - t e s t . 76 TABLE IV-10 B l o o d b i o c h e m i s t r y i n s u b j e c t s from b o i a - f r i a and w e l l - t o - d o f a m i l i e s i n comparison w i t h normal v a l u e s . Parameter Norma 1 a Mean e x p r e s s e d as % normal v a l ue Va l u e B o i a - F r i a Wel1-to- •do Hematocr i t > 40.6% 96.8 (38) b 103-4 (3D Hemog1ob i n > 13-9 g/100 ml 110.1 (38) 118.0 (3D Serum i ron > 60.0 yg/100 ml 134.2 (35) 138.0 (30) T r a n s f e r r i n s a t u r a t i on > 20% 125.5 (34) 132.0 (29) Serum t o t a l p r o t e i n > 6.0 g/100 ml 126.2 (33) 118.7 (30) Serum a l b u m i n > 3-5 g/100 ml 132.6 (34) 126.3 (30) a S a u b e r l i c h e t aj_. , 1974. b F i g u r e s i n p a r e n t h e s e s denote number o f s u b j e c t s . TABLE IV-11 Number of subjects having biochemical parameters below normal value Parameter B o i a - f r i a Number of subjects ' Wel1-to-do Hematocri t Hemog1ob i n Serum i ron T rans fe r r in saturat ion Serum tota l prote in Serum albumin 22 (57-9) 5 (13.2) 14 (40.0) 16 (47.1)' 0 0 10 (32.3) 3 ( 9-7) 9 (30.0) 8 (27.6) 1 ( 3-3) 2 ( 6.7) a Figures in parentheses denote % of tota l in group. b Values for b o i a - f r i a and we l l - to -do subjects are s i g n i f i c a n t l y d i f f e ren t (p < .01) using chi -square tes t . 78 s t a t i s t i c a l l y s i g n i f i c a n t for hematocrit and t r a n s f e r r i n sa tura t ion . 2. Assessment of Physical Work Performance Figure IV-10 i l l u s t r a t e s the change in heart rate with time and in response to increas ing sub-maximal work load in both b o i a - f r i a and wel l -do- do subjects . Excluding the i n i t i a l 3 minutes and the f i n a l 1 minute, heart rate was s i g n i f i c a n t l y higher in b o i a - f r i a than in we l l - to -do sub- j ec t s at every minute of t e s t i ng . The mean values for maximum, minimum, and change in heart rate are shown in Table IV-12 for both groups. The maximum heart rate and the change in heart rate are both s i g n i f i c a n t l y higher in boi a - f r ia than in we 11-to-do subjects . Changes in blood l a c t i c ac id in response to exerc i se are shown in Table IV—13- Blood l a c t i c acid levels a f t e r exerc i se were s i g n i f i c a n t l y greater in b o i a - f r i a than in we l l - to -do subjects . However, although bo ia - f r i a subjects showed greater actual and percentage increases in l a c t i c ac id with exerc i se than we l l - to -do subjects , these d i f fe rences between the two groups were not s i g n i f i c a n t . The standard dev iat ion was very high in values obtained for blood l a c t i c a c id . 3. Assoc iat ion Between Nut r i t i ona l Status and Physical Work Performance Pearson c o r r e l a t i o n c o e f f i c i e n t s were obtained for the fo l lowing combinations of va r i ab le s : maximum heart rate with a l l other va r i ab l e s ; change i n hea rt rate wi th a l l other va r i ab le s ; actual increase in l a c t i c ac id with a l l other va r i ab l e s ; and percentage increase in l a c t i c ac id with a l l other va r i ab l e s . Table IV-lA shows those pairs of var iab les for which Pearson c o r r e l a t i o n was s i g n i f i c a n t at the 33% level or bet ter . Var iab le pa irs for which no s i g n i f i c a n t c o r r e l a t i o n was obtained are not reported. Maximum heart rate was s i g n i f i c a n t l y cor re la ted with weight, height, 79 a Values are sample mean b-d Values for b o i a - f r i a and we l l - to -do subjects are s i g n i f i c a n t l y d i f f e r e n t using Student's one - ta i l ed t - t e s t : b p < .001 c p <. .01 d p < .05 80 TABLE IV-12 Comparison of change in heart rate in subjects from b o i a - f r i a and we l l - to -do f am i l i e s . Mean ± SD Parameter Boi a - f r i a (n = 3D We 11-do-do (n = 30 ) Maximum heart rate (beats/min) 1 7 7 . 4 ± 1 5 . 9 a 1 6 1 . 4 ± 17. . 1 Mi n i mum heart rate (beats/min) 8 7 . 7 ± 1 3 . 0 8 4 . 5 ± 10 . 8 Change in heart rate (beats/min ) 8 9 . 6 ± 1 6 . 6 b 7 6 . 9 ± 14. • 9 a-b Values for b o i a - f r i a and d i f f e r e n t using Student's we l l - to -do subjects are one-ta i1ed t - t e s t : s igni f i cant ly a p < .001 b p < .01 81 TABLE IV-13 Comparison of blood l a c t i c acid levels before and a f te r exerc i se in subjects from b o i a - f r i a and we l l - to -do f am i l i e s . Parameter Mean + SD Bo ia -F r i a Wel1-to-do Lact i c acid (mg/100 ml) before exerc i se 1 1 . • Ik + 5. 19(32) 10. • 35 + 4.37(30) Lac t i c acid (mg/100 ml) a f t e r exerc i se 18, .87 + 6. • 19(30) b 14. .91 + 6.10(28) Increase in (mg/100 ml) l a c t i c ac id 6, .98 + 5. 54(30) 4. • 98 + 4.51(28) Increase in l a c t i c ac id (%) 71. • 3 + 66. 7 (30) 52. .5 + 48.8 (28) a Figures in parentheses denote number of subjects . b Values for b o i a - f r i a and we l l - to -do subjects are s i g n i f i c a n t l y d i f f e r e n t (p < .01) using Student's one - ta i l ed t - t e s t . 82 arm c i r c u m f e r e n c e , arm muscle c i r c u m f e r e n c e , and, t o a l e s s e r e x t e n t , w i t h d i e t a r y v i t a m i n A, b l o o d l a c t i c a c i d a f t e r e x e r c i s e , d i e t a r y v i t a m i n C, and d i e t a r y r i b o f l a v i n . Change i n h e a r t r a t e was s i g n i f i c a n t l y c o r r e l a t e d w i t h w e i g h t , h e i g h t , arm c i r c u m f e r e n c e , arm muscle c i r c u m f e r e n c e , and, t o a l e s s e r e x t e n t , w i t h serum a l b u m i n and d i e t a r y v i t a m i n A. C o e f f i c i e n t s o f d e t e r m i n a t i o n were r e l a t i v e l y low (.09 t o .kl) f o r a l l v a r i a b l e s c o r r e l a t e d . TABLE IV-14 C o r r e l a t i o n s between s e l e c t e d p a i r s o f v a r i a b l e s . A s s o c i a t e d v a r i a b l e s P earson c o r r e 1 a t i on c o e f f i c i e n t ( r ) C o e f f i c i e n t o f d e t e r m i n a t i o n ( r 2 ) Maximum h e a r t r a t e w i t h : w e i g h t - . 6 l 7 b .38 h e i g h t - . 6 4 5 b .42 arm c i r c u m f e r e n c e -.563^ -32 arm muscle c i r c u m f e r e n c e -.511° -33 d i e t a r y v i t a m i n A - . 4 2 5 b .18 p o s t - e x e r c i s e b l o o d l a c t i c a c i d +.338C .11 d i e t a r y v i t a m i n C -.309 -10 d i e t a r y r i b o f l a v i n -.307° .09 Change i n h e a r t r a t e w i t h : w e i g h t -.564 .32 h e i g h t - . 5 9 0 b .35 arm c i r c u m f e r e n c e -.523^ -27 arm muscle c i r c u m f e r e n c e - . 5 5 3 b -31 serum a l b u m i n --365° -13 d i e t a r y v i t a m i n A - . 3 0 2 c .09 a b c B o i a - f r i a and we l l - to -do subjects treated as one group. S t a t i s t i c a l l y s i g n i f i c a n t (p < .001). S t a t i s t i c a l l y s i g n i f i c a n t (p < .01). 84 CHAPTER V DISCUSSION 1 . Socio-economic Considerations V i s i t s to local homes and markets y ie lded information that large ly confirmed the f indings of other recent ly published authors (Desai et a 1 . , 1980) who reported genera l ly poor l i v i n g condit ions among B r a z i l i a n migrant workers. L i v ing condi t ions of boi a - f r i a fami1i es were found to be poor in th i s study as we l l . Housing was crowded and d i r t y , and indoor running water, e l e c t r i c i t y , and sewage f a c i l i t i e s were frequent ly non- exi s tant . In cont ras t , we l l - t o -do fami l ie s l i ved in homes that were spacious, c l ean , and f u l l y equipped with modern amenit ies. As w e l l , income levels of bo i a - f r i a f ami l ie s were estimated in th is study to be roughly ten times lower than those of we l l - to -do f am i l i e s . This is despite the fact that i t has been documented that b o i a - f r i a fami1ies frequent ly paid higher food pr ices than we l l - to -do fami l ie s (Swann, 1979)- Many previous studies in B raz i l have reported that low incomes are a major factor which severely l im i t s people ' s a b i l i t y to feed themselves adequately (Jansen e_t aj_. , 1977; A lves, 1977; Gu i t t i e_t aj_., 1977; S i gu 1 em et^ aj_. , 1978; and Szar farc , 1979). It is l i k e l y that the low incomes of b o i a - f r i a fami1ies in the present study were a l so l i m i t i n g the i r a b i l i t y to purchase an adequate d i e t . Stores in the favela areas o f fered l i t t l e se lec t i on of fresh produce, animal prote in sources, or dairy products. The time and expense of t r a v e l l i n g to the c i t y center where a greater var ie ty of good were a v a i l - 85 a b l e would p r o b a b l y p r e c l u d e boi a - f r i as from p u r c h a s i n g t h e s e items even i f t h e y were a f f o r d a b l e . Hence, most p e o p l e r e l i e d on cheap s t a p l e s l i k e w h i t e r i c e , beans, w h i t e b r e a d , c o f f e e , and sugar t o make up t h e i r d i e t . The g e n e r a l h e a l t h o f s u b j e c t s i n the p r e s e n t s t u d y was o n l y a s s e s s e d i n a l i m i t e d way. S t i l l , s t a t i s t i c a l l y s i g n i f i c a n t " d i f f e r e n c e s were found between b o i a - f r i a and w e l l - t o - d o s u b j e c t s . A g r e a t many more b o i a - f r i a than w e l l - t o - d o s u b j e c t s p r e s e n t e d e v i d e n c e o f c a r d i a c a n o m a l i e s and b r o n c h i a l i n f e c t i o n s . A l t h o u g h i t was not t e s t e d f o r i n t h i s s t u d y , p r e v i o u s s t u d i e s ( A n g e l e l i , 1978 and Desai et_ a_l_., 1980) have shown t h a t many b o i a - f r i a a d u l t s and c h i l d r e n a l s o s u f f e r e d from p a r a s i t i c i n f e s t a - t i o n . The e x i s t a n c e o f h e a l t h problems such as b r o n c h i a l i n f e c t i o n s and p a r a s i t i c i n f e s t a t i o n was not s u r p r i s i n g g i v e n the crowded and u n s a n i t a r y c o n d i t i o n s t h e s e p e o p l e l i v e d i n . The h i g h i n c i d e n c e o f b r o n c h i a l i n f e c - t i o n c o u p l e d w i t h h i g h r a t e s o f p a r a s i t i c i n f e s t a t i o n a r e f a c t o r s which a l s o p r o b a b l y g r e a t l y a g g r a v a t e any n u t r i t i o n a l d e f i c i e n c i e s e x i s t i n g among b o i a - f r i a c h i l d r e n . The s i g n i f i c a n c e o f the h i g h e r i n c i d e n c e o f c a r d i a c a n o m a l i e s o b s e r v e d i n b o i a - f r i a s u b j e c t s as compared t o w e l l - t o - do s u b j e c t s i s not c l e a r and p r o b a b l y w a r r a n t s f u r t h e r s t u d y . To summarize, b r i e f s o c i o - e c o n o m i c and e c o l o g i c a l assessment y i e l d e d e v i d e n c e t h a t i m p o v e r i s h e d l i v i n g c o n d i t i o n s , low incomes, and the p r e s e n c e o f i n f e c t i o n s were f a c t o r s t h a t b o i a - f r i a c h i l d r e n had t o contend w i t h i n t h e i r d a i l y l i v e s . These f a c t o r s p r o b a b l y s y n e r g i s t i c a 1 1 y i n f l u e n c e d and a g g r a v a t e d any n u t r i t i o n a l problems e x i s t i n g among t h e s e c h i l d r e n . In c o n t r a s t , t h e s e f a c t o r s appeared t o be a b s e n t from the l i v e s o f most w e l l - t o - d o s u b j e c t s . I t i s u n l i k e l y t h a t n u t r i t i o n a l problems o f b o i a - f r i a c h i l d r e n c o u l d be a m e l i o r a t e d w i t h o u t s i m u l t a n e o u s l y a m e l i o r a t i n g 86 these socio-economic problems . 2. Assessment of Nut r i t i ona l Status a) Dietary Ana lys i s The d ie t reca l l method which was used in th i s study f/or d ietary assessment has s p e c i f i c l im i ta t ions and inherent e r ro r s , namely: subjects may not remember food intake accura te ly ; there is no est imation of usual intake; intake may be overestimated when low or underestimated when high; and th i s method cannot be used to assess intake of i nd i v i dua l s , only of populations (Beaton et_ a_l_. , 1979; Linusson et_ a_j_. , 1974; Madden et al . , 1976; Garn e_t aj_. , 1978; and Stapleton and Abernathy, 1930) . Keeping these l im i ta t i ons in mind, the d ietary f indings of th is study sha l l be d iscussed. The mean da i l y intake of b o i a - f r i a s was less than wel l - to -do subjects for a l l nutr ients examined with the exception of a - tocophero l . These d i f fe rences were s i g n i f i c a n t for the fo l lowing nu t r ien t s : energy, p ro te in , ca lc ium, i r on , vitamin A, thiamin, r i b o f l a v i n , and vitamin C. When mean da i l y intakes of both groups were compared to WHO/FAO recommended intakes (Passmore et^ aj_. , 1974), i t was found that boi a-f r i as consumed less than 2/3 of the recommended intake for energy, ca lc ium, thiamin, r i b o f l a v i n , and niiacin. On the other hand, we l l - to -do subjects consumed over 2/3 of the recommended intake for a l l nutr ients considered. While i t is not poss ib le from simple comparison with the recommended d a i l y intake to d iscern whether de f inc ien t intakes t ru l y e x i s t , i t is poss ib le to assert that there is some p robab i l i t y of d e f i c i e n t intakes i f many subjects consume subs tan t i a l l y less than the recommended intake (Beaton, 1975)- For the purpose of th i s study, the f i gure 2/3 of the recommended intake was chosen to be a rough ind icator of low intake. 87 Further inspect ion of the data showed that for the fo l lowing nu t r i en t s , 60-80% of bo i a - f r i a subjects had intakes below 2/3 of the recommended intake: energy, ca lc ium, thiamin, r i b o f l a v i n , n i a c i n , and vitamin C. Comparatively, the only nutr ient for which over 60% of we l l - to -do subjects consumed below 2/3 of the recommended intake was n i a c i n . From the d ie tary data obtained in th i s study then, i t appears that the probabi1ity ' is greater that b o i a - f r i a s consumed low nutr ient intakes, than that we l l - to -do subjects d id . It a l so appears that i f b o i a - f r i a subjects were at r i sk of having low intakes of any nu t r i en t s , they would include these: energy, ca lc ium, thiamin, r i b o f l a v i n , n i a c i n , and vitamin C. Any conclusions more d e f i n i t i v e than th i s are not j u s t i f i a b l e given the l imi ted nature of the d ietary reca l l method. Energy intakes and overa l l quant i t i e s of food consumed have f r e - quently been reported to be low among B r a z i l i a n populations (ICNND, 1965 and Shrimpton, 1975), e s p e c i a l l y those from the lowest socio-economic c lasses (Patr ick and Simoes, 1971 and Jansen et_ aj_., 1977). The low mean energy intake, inc luding energy intake per unit of body weight, of boi a- f r i a subjects reported in th i s study suggests that overa l l quant i t ies of food consumed may have been low. As w e l l , most energy in the b o i a - f r i a d ie t was derived from r i c e , beans, and bread, a f ind ing which is cons i s - tent with previous studies (Angelel i , 1978 and Desai et^ a_l_. , 1980) which found bo i a - f r i a d iets to be qu i te monotonous. Wel l - to-do subjects appeared to be at l i t t l e r i sk of consuming low energy intakes. In the we l l - to -do d i e t , most energy came from animal prote in sources such as beef, ch icken, or eggs. S i g n i f i c a n t percentages of energy in the d iet were a l so contr ibuted by r i c e , bread, sugar and sweets, and dairy products. This would seem to ind icate that there was 88 much g r e a t e r v a r i e t y i n t h e w e l l - t o - d o than t h e b o i a - f r i a d i e t . Mean i n t a k e s o f p r o t e i n i n both b o i a - f r i a and w e l l - t o - d o s u b j e c t s appeared t o be adequate. P r e v i o u s s t u d i e s on p r o t e i n i n t a k e s o f B r a z i l i a n p e o p l e have y i e l d e d d i f f e r i n g r e s u l t s . S e v e r a l s t u d i e s c o n d u c t e d i n v a r i o u s r e g i o n s o f B r a z i l i n c l u d i n g Sao P a u l o (ICNND, 1965; Campi no e t a l . , 1975; and P a t r i c k and Simoes, 1971) found e v i d e n c e o f d e f i c i e n t i n t a k e s among both c h i l d r e n and a d u l t s . But r e s u l t s o f o t h e r s t u d i e s , a g a i n c o nducted i n v a r i o u s r e g i o n s o f the c o u n t r y i n c l u d i n g Sao P a u l o (Vargas F o u n d a t i o n as c i t e d by S h r i m p t o n , 1975; M a r t i n s et_ aj_. , 1977; and Desai e t a l . , 1980) found p r o t e i n i n t a k e s t o be g e n e r a l l y adequate. A st u d y c o n d u c t e d i n t h e R i b e i r a o P r e t o a r e a by S a n t o s 1 group (1979) found t h a t the t r a d i t i o n a l B r a z i l i a n r i c e and bean d i e t can s u p p l y adequate p r o t e i n f o r c h i l d r e n i f consumed i n s u f f i c i e n t q u a n t i t i e s . I t appears t h a t t h i s h o l d s t r u e f o r c h i l d r e n i n the p r e s e n t s t u d y . C a l c i u m i s a n u t r i e n t w h i c h has not been f r e q u e n t l y s t u d i e d i n B r a z i l i a n p o p u l a t i o n s . Food i n t a k e s t u d i e s have i n d i c a t e d t h a t consump- t i o n o f d a i r y p r o d u c t s i s low among many B r a z i l i a n s , i n c l u d i n g s c h o o l - a g e c h i l d r e n (Chaves, 1964; A r i g e l e l i , 1978; Rosenberg, 1977; and Desai e t a l . , 1980). These s t u d i e s have r e p o r t e d t h a t s c h o o l - a g e c h i l d r e n from low- income f a m i l i e s f r e q u e n t l y consumed as much as one g l a s s o f m i l k a day, but i t i s d o u b t f u l t h a t t h i s q u a n t i t y was s u f f i c i e n t t o meet the c a l c i u m r e q u i r e m e n t s o f a gro w i n g c h i l d u n l e s s o t h e r c a l c i u m s o u r c e s were a l s o consumed. In the .present s t u d y , i n s p e c t i o n o f bo i a - f r i as' d i e t r e c a l l s showed consumption o f d a i r y p r o d u c t s was v e r y l i m i t e d , o f t e n no more than a few ounces o f m i l k taken i n c o f f e e once o r t w i c e a day. In k e e p i n g w i t h t h e f i n d i n g s o f p r e v i o u s B r a z i l i a n s t u d i e s c i t e d above, i t i s p r o b a b l e 89 t h a t c a l c i u m i n t a k e s o f bo i a - f r i a s u b j e c t s i n t h i s s t u d y were a t r i s k o f b e i n g d e f i c i e n t . In c o n t r a s t , most w e l l - t o - d o s u b j e c t s consumed d a i r y p r o d u c t s f r e q u e n t l y and had d a i l y i n t a k e s c l o s e t o t he recommended i n t a k e . I ron i n B r a z i l i a n d i e t s has not o f t e n been r e p o r t e d t o be i n a d e q u a t e , t he main e x c e p t i o n t o t h i s b e i n g t h e v e r y low i r o n i n t a k e s t h a t were r e p o r t e d f o r a d u l t b o i a - f r i a women i n a r e c e n t R i b e i r a o P r e t o s t u d y (Desa i et_ aj_. , 1980). Mean i n t a k e s o f i r o n f o r a l l s u b j e c t s i n the p r e s e n t s t udy appea red t o be a d e q u a t e . However,'75% o f i r o n i n t he b o i a - f r i a d i e t came f rom p l a n t o r non-heme s o u r c e s and may not have been r e a d i l y a v a i l a b l e t o t h e body. V i t a m i n A i n t a k e s i n t h i s s t u d y d i d not appea r t o f o l l o w t he t r e n d no ted i n p r e v i o u s s t u d i e s o f Sao P a u l o f a m i l i e s w h i c h r e p o r t e d v e r y low d i e t a r y i n t a k e s ( M a r t i n s et_ a j _ . , 1977; Roncada , 1972; and Desai e t a l . , 1980). However, i t can be d i f f i c u l t t o i n t e r p r e t r e s u l t s o f d i e t - r e c a l l s t u d i e s f o r n u t r i e n t s l i k e v i t a m i n A where d a i l y i n t a k e s v a r y g r e a t l y . As S t a p l e t o n and A b e r n a t h y (1980) p o i n t e d o u t , r e s u l t s o f such s t u d i e s a r e se ldom a c c u r a t e f o r n u t r i e n t s l i k e v i t a m i n A u n l e s s numerous d i e t r e c a l l i n t e r v i e w s a r e c o n d u c t e d w i t h each s u b j e c t . Hence, an a c c u r a t e q u a n t i t a t i v e i n t e r p r e t a t i o n o f v i t a m i n A i n t a k e s r e p o r t e d i n t h i s s t u d y i s p r o b a b l y not p o s s i b l e . The d i e t a r y a s se s sment o f B r a z i l i a n p e o p l e w i t h r e s p e c t t o t h i a m i n , r i b o f l a v i n , and n i a c i n i n t a k e s has r e c e i v e d l e s s a t t e n t i o n i n the p a s t than has a s se s sment o f p r o t e i n , e n e r g y , o r v i t a m i n A i n t a k e s , a l t h o u g h s e v e r a l s t u d i e s have r e p o r t e d low v i t a m i n B i n t a k e s among l ow- i ncome Sao P a u l o s u b j e c t s ( M a r t i n s e t a l . , 1977; W i l s o n e t a l . , 1977; and Desa i et^ a_l_., 1980) . T h i s s t u d y appea r s t o c o n f i r m t h e s e p r e v i o u s f i n d i n g s f o r s e v e r a l 90 reasons. F i r s t , 70-80% of b o i a - f r i a subjects consumed less than 2/3 of the recommended d a i l y intake for thiamin, n i a c i n , and r i b o f l a v i n , suggest- ing that the p robab i l i t y ex i s t s that there were low intakes of these nu t r ien t s . Second, a l l bo i a - f r i a subjects reported eat ing white ref ined r i ce and bread in substant ia l amounts in the i r d i e t s . Flour and cereals are not enriched in B r a z i l a f t e r re f in ing (Desai et_ aj_., 1980), and sub- s t a n t i a l amounts of B vitamins may be lost during the commercial m i l l i n g of r i ce and wheat f l o u r . F i n a l l y , B vitamins may a l so be lost through prolonged cooking of beans and r i c e . Considering these f a c t s , b o i a - f r i a s were probably at r i sk of having low B vitamin intakes. Wel l - to-do subjects presented a better p i c tu re : most had high intakes of thiamin and r i b o f l a v i n , although n iac in intakes were lower. Major sources of these three B vitamins in the we l l - to -do d ie t were meat, eggs, and da iry products. Thus, we l l - to -do subjects were much less a f fec ted than boi a - f r i as by B vitamin losses which occurred through commercial r e f i n ing of r i ce and wheat f l o u r . Dietary intakes of vitamin C have not been widely studied among B r a z i l i a n people, although mean intakes as low as 50% of recommended intake have been reported among poorer socio-economic groups (Patr ick and Simoes, 1971; Martins et^ aj_. , 1977; and Desai et^ aj_. , 1980). The b o i a - f r i a mean intake of v i t a m i n C was nearly 150% of the recommended intake, but t h i s f i gure obscures the fact that while a few ind iv idua l s consumed very large amounts of vitamin C, over 60% of subjects consumed intakes of less than 2/3 of the recommended intake. Considering, too, that b o i a - f r i a s consumed very l imi ted amounts of fresh f r u i t and vegetables, which are superior d ietary sources of vitamin C, i t is l i k e l y that low vitamin C intakes occurred. 91 The mean vitamin C intake of we l l - to -do subjects was nearly 500% of the recommended intake! Considering as well that 75% of we l l - to -do subjects consumed over 2/3 of the recommended intake, and that most of these ch i ld ren reported frequent consumption of fresh f r u i t s and vegetables, i t is un l i ke ly that the i r vitamin C intakes were Inadequate. In summary, the b o i a - f r i a d iet was very monotonous. Most meals con- s i s ted mainly of bread, r i c e , and beans. Consumption of da i ry products, f r u i t , vegetables, and animal prote in sources appeared to be very l im i ted . Comparatively, the higher socio-economic status of we l l - to -do subjects was re f l ec ted in the greater va r ie ty and the preponderance of more expen- s ive foods such as meat, seafood, and confect ions in the i r d i e t . Judging from the d ie t r e c a l l s , b o i a - f r i a subjects a l so consumed a lower quant i ty , as well as q u a l i t y , of food. If b o i a - f r i a subjects were at r i sk o f con- suming low intakes of any nut r ient s , those nutr ients would probably i n - c lude: energy, ca lc ium, thiamin, r i b o f l a v i n , n i a c i n , and vitamin C. b) Anthropometric Determinations A l l anthropometric parameters measured in th is study were found to be s i g n i f i c a n t l y lower in b o i a - f r i a than in we l l - to -do subjects . Large d i f fe rences between b o i a - f r i a and we l l - to -do subjects were a l so observed when anthropometric parameters were compared to American and B r a z i l i a n standa rds. In comparison to American standards (Nelson et a 1., 1979). weights of most b o i a - f r i a subjects f e l l below 90% of the standard, ind ica t ing f i r s t degree ma lnutr i t ion according to the Gomez (1956) c l a s s i f i c a t i o n . However, mean weight of we l l - to -do subjects exceeded the American standard by 20%, poss ib ly ind ica t ing overweight, although the comment should be 92 made here that most we l l - to -do subjects appeared large for age but not obese. Mean heights of both b o i a - f r i a and we l l - to -do subjects f e l l w i th in 10% of the American standard, ind icat ing normal height according to the Gomez (1956) c l a s s i f i c a t i o n . B o i a - f r i a subject s ' mean weight was very s im i l a r to the B r a z i l i a n standard; whereas, we l l - to -do subjects ' mean weight exceeded the B r a z i l i a n standard by 50%! Mean heights of b o i a - f r i a and we l l - to -do subjects f e l l w i th in 10% of the B r a z i l i a n standard. It should be noted that the B r a z i l i a n standards for height and weight used here were derived from a study of ch i l d ren of low socio-economic status (Marcondes et_ a_l_. , 1971). These so - ca l l ed standards are widely used in B raz i l (Shrimpton, 1975), even though J e l l i f f e (1966) has cautioned that the use of such standards in developing countr ies is deceiv ing because they provide a p ic ture of development achieved by c h i l - dren who are probably n u t r i t i o n a l l y compromised. J e l l i f f e (1966) suggested that local standards are only meaningful i f prepared from growth patterns of ch i l d ren from upper socio-economic s t ra ta who have had the opportunity to consume adequate d i e t s . Thus, the resu l t s of the present study indicate that b o i a - f r i a subjects are comparable in terms of height and weight to other B r a z i l i a n ch i l d ren of low socio-economic s tatus . But th is hardly indicates that optimal growth was achieved. Rather, comparisons with both we l l - to -do subjects and American standards suggest that b o i a - f r i a subjects were ac tua l l y underweight for age and for height. Thus i t would appear that acceptable local B r a z i l i a n standards for height and weight have yet to be found. Numerous studies have indicated height and weight in B r a z i l i a n 93 c h i l d r e n . Early studies conducted in Ribeirao Preto (Dutra de O l i v e i r a et_ a]_. , 1964) and in northeast B raz i l (ICNND, 1965) found both heights and weights of ch i ld ren to be well below American standards. More recent B r a z i l i a n studies confirmed th is f ind ing for ch i ld ren from low-income f a m i l i e s , and found that ch i ld ren from upper socio-economic c lasses tended to surpass American standards for both height and weight (Campino et a 1., 1975; Sigulem e_t a_l_. , 1976; Gu i t t i et_ aj_., 1977; Tur in i e_t_ aj_. , 1978; and Desai e_t aj_., 1981) . B o i a - f r i a subjects in th i s study were genera l ly short and very th in in comparison with the i r we l l - to -do counterparts. However, the fact that they had normal heights compared to American standards suggests that undernutr i t ion in these ch i ld ren was not so severe as to stunt growth. Thus, undernutr i t ion may have been less severe here than for ch i ld ren researched in previous s tud ies . There is support for this in that d ie tary assessment . indicated prote in intakes were probably adequate among b o i a - f r i a ch i l d ren in the present study. B r a z i l i a n standards do not ex i s t for upper-arm circumference, t r i - ceps sk in fo ld th ickness , or upper-arm-muscle c ircumference, so in th i s study American standards (Frisancho, 1974) were used. Mean values for arm circumference and arm-muscle circumference in both b o i a - f r i a and we l l - to -do subjects f e l l with in 10% of standard va lues, ind ica t ing adequate development. But b o i a - f r i a subjects ' mean values for t r i ceps sk in fo ld thickness were very low: less than 60% of the standard. Comparatively, we l l - to -do subject s ' mean sk in fo ld thickness approximated 100% of the standard. In a previous study on t r i ceps sk in fo ld thickness in B r a z i l i a n ch i l d ren (Hegg, 1978) values were c i t ed f o r subjects who were 11 years 94 o l d , one y e a r younger than the mean age o f s u b j e c t s i n t he p r e s e n t s t u d y . N e v e r t h e l e s s , t h e s e p r e v i o u s v a l u e s were a p p r o x i m a t e l y t w i c e t h o s e found he re f o r b o i a - f r i a s u b j e c t s . C h i l d r e n i n Hegg ' s ( 1 9 7 8 ) s t u d y came f rom i n t e r m e d i a t e o r h i g h s o c i o - e c o n o m i c g r o u p s . A s t u d y done i n R i b e i r a o P r e t o (Desa i e t a l . , 1981) y i e l d e d r e s u l t s s i m i l a r t o t he p r e s e n t s t u d y f o r t r i c e p t s s k i n f o l d t h i c k n e s s . The v e r y low b o i a - f r i a v a l u e s o b t a i n e d f o r t r i c e p s s k i n f o l d t h i c k n e s s i n d i c a t e t h a t t h e s e s u b j e c t s p r o b a b l y had v e r y low f a t r e s e r v e s . The f a c t t h a t arm c i r c u m f e r e n c e and a rm-musc l e c i r c u m f e r e n c e o f t h e s e s u b j e c t s d i d not f a l l be low s t a n d a r d s s u g ge s t s t h a t u n d e r n u t r i t i o n , w h i l e s e v e r e enough t o p r e v e n t a c c u m u l a t i o n o f f a t s t o r e s , was not s e v e r e enough t o cau se musc l e w a s t i n g . W e l l - t o - d o c h i l d r e n had mean v a l u e s f o r t r i c e p s s k i n f o l d t h i c k n e s s t h a t d i d not g r e a t l y exceed s t a n d a r d v a l u e s . T h i s i s i n agreement w i t h t he o b s e r v a t i o n t h a t w e l l - t o - d o s u b j e c t appea red t o be b i g - b o n e d and w e l l - m u s c l e d , but not g e n e r a l l y o b e s e . To summar ize the a n t h r o p o m e t r i c f i n d i n g s o f t h i s s t u d y , i t appea r s t h a t bo i a - f r i a c h i l d r e n were s h o r t e r and had l e s s e r f a t s t o r e s than t h e i r w e l l - t o - d o c o u n t e r p a r t s . U n d e r n u t r i t i o n i n b o i a - f r i a s seemed t o be m a n i f e s t e d m a i n l y i n low body w e i g h t s and low f a t s t o r e s f o r h e i g h t and a ge , r a t h e r than i n s t u n t e d g rowth o r musc l e w a s t i n g . T h i s i s i n c ompa r i s on w i t h Amer i c an s t a n d a r d s . These r e s u l t s c o u l d be i n t e r p r e t e d much more m e a n i n g f u l l y i f a p p r o p r i a t e l o c a l B r a z i l i a n a n t h r o p o m e t r i c s t a n d a r d s e x i s t e d . c) B i o c h e m i c a l T e s t s The b i o c h e m i c a l t e s t s c o n d u c t e d i n t h i s s t u d y a s s e s s e d t he s t a t u s o f two n u t r i e n t s : i r o n and p r o t e i n . W h i l e t he t e s t s used t o a s s e s s i r o n 95 status included some that are general ly regarded to be good ind icators of body iron stores (Cook and F inch, 1979 ) , the tests used to assess prote in status have l im i ta t i ons in s e n s i t i v i t y (Sauberl ich et_ aj_. , 1974) and sha l l be discussed with th i s in mind. B o i a - f r i a and we l l - to -do groups were found to s i g n i f i c a n t l y d i f f e r from each other in values obtained for hemotocrit, hemoglobin, and serum to ta l p ro te in . B o i a - f r i a values were lower than we l l - to -do for hematocrit and hemoglobin, but higher for serum total p ro te in . When compared to normal values (Sauberl ich et_ a\_. , 1974 ) , mean values for a l l parameters measured in both bo i a - f r i a and we l l - to -do subjects appeared to be adequate or to marginal ly exceed normal va lues. However, there was a very high standard dev iat ion in values obtained for both serum iron and t r a n s f e r r i n sa tura t ion , which makes mean values d i f f i c u l t to i n te rp re t . In f ac t , 40 -60% of b o i a - f r i a subjects had hematocrit, serum i r o n , and t r a n s f e r r i n saturat ion values below normal, suggesting some, cause for concern about i ron s tatus . Previous biochemical studies of iron status of B r a z i l i a n people have usua l ly examined hemoglobin and hematocrit, which are both late-stage ind icators of i r o n - d e f i c i e n c y . Two previous Sao Paulo studies found as many as k0% of v i l l a g e populations had low hemoglobin leve ls (Szarfarc, 1972 and Sigulem et_ aj_. , 1 978 ) ; while two Ribeirao Preto studies found that hematocrit and hemoglobin leve ls were genera l ly adequate among low- income ch i ld ren and adults (Dutra de O l i v e i r a et a 1•, 1964 and A n g e l e l i , 1978 ) . Most recent l y , a Ribeirao Preto survey of adult b o i a - f r i a s found that 25% of subjects had low hemoglobin values. Results of these studies may not agree, but cons ider ing that they measured late-stage ind icators or iron d e f i c i e n c y , any evidence of low values is cause for concern. 96 In the present study, a substant ia l number of b o i a - f r i a subjects presented low values for both t r an s f e r r i n sa tura t ion , an ear ly ind icator of i r o n - d e f i c i e n c y , and hematocrit, a la te ind ica tor . Many b o i a - f r i a ch i l d ren have been shown to su f fe r from p a r a s i t i c in fes ta t ion (Desai et al . , 1980) which can cause regular blood losses and increased iron requirements. In add i t i on , d ietary assessment showed that most b o i a - f r i a s consumed mainly plant source or non-heme iron which, e s p e c i a l l y in the absence of vitamin C, may not be read i ly ava i l ab le in the body. In view of these f a c t s , iron status of boi a - f r i a subjects may well have been marginal and warrants fur ther study. Most we l l - t o -do subjects presented normal values for a l l parameters of iron status measured. This re lates well with d ietary data that showed mean iron intakes to be almost twice the recommended intake, and which showed that most iron in the wel l - to -do d iet was derived from animal sources, where iron is more h ighly a v a i l a b l e . In the present study, serum tota l prote in and albumin leve l s were genera l ly adequate among a l l subjects s tudied. Serum albumin, as has been d iscussed, is a more meaningful ind ica tor of prote in status than serum tota l prote in because albumin leve l s become depressed much e a r l i e r in prote in de f i c i ency (Sauberl ich e_t̂  aj_. , 1974). The general ly adequate serum albumin leve ls found here ind icate that prote in status is probably acceptable in the subjects of th i s study. These biochemical f ind ings are in agreement with the d ietary assess- ment conducted in th i s study which found mean protein intakes were a lso probably adequate. Few previous studies have measured both serum tota l prote in and albumin in B r a z i l i a n populat ions. The ICNND (1965) reported a high incidence of sub-normal values for serum tota l prote in in north- 97 east B raz i l but thi.s is not a good ind icator of prote in de f i c i ency . More recent l y , Angele l i (1978) found normal mean values for serum prote in and albumin in adult migrant workers in Ribeirao Preto, but: no studies were done of chi1dren. In summary then, biochemical assessment y ie lded evidence that iron status may be marginal among b o i a - f r i a but not among we l l - to -do ch i ld ren in the present study. Protein status was found to be adequate in both groups of ch i1dren. 3. Assessment of Physical Work Performance In th i s study, phys ica l work performance was assessed by measuring change in heart rate and change in blood l a c t i c ac id in response to a standardized bicycle-ergometer work test . Many factors can confound resu l ts of work tests such as these, i n - c lud ing : age, sex, c l imate, food intake p r i o r to t e s t i n g , and habitua- t ion to exerc i se . These factors were cont ro l l ed in the fo l lowing way in th i s study: a l l subjects were approximately the same age; a l l subjects were males; and a l l subjects performed work tests at the same room temperature and a l t i t u d e . Food intake p r i o r to exerc ise was less wel1-control 1ed because sub- jec t s consumed co f f ee , milk, sugar, and sometimes bread or j u i c e in the i r homes before being tes ted. It was not poss ib le to standardize th i s pre - exerc i se food consumption. Habituation to exerc i se was con t ro l l ed for in so far as subjects were questioned about the i r usual leve ls of phys ica l a c t i v i t y . B o i a - f r i a and we l l - to -do subjects appeared to be s im i l a r in terms of usual leve ls of physical a c t i v i t y , but i t is acknow- ledged that the evidence used to determine th is was e s s e n t i a l l y q u a l i t a - t i ve in nature. 98 Mean heart rate at every minute of exerc i se tes t ing excluding rest periods was s i g n i f i c a n t l y greater in b o i a - f r i a than in we l l - to -do subject s . Maximum heart rate and maximum change in heart rate were a l so s i g n i f i - cant ly higher for b o i a - f r i a subjects . These higher heart rates are taken to be evidence that work performance was poorer in b o i a - f r i a subjects than in we l l - to -do subjects . This f ind ing is in keeping with the resu l t s of several previous studies which found heart rates to be higher in undernourished than in wel1-nourished subjects when both performed the same work task (Desai et_ a_l_. , 1981 ; Satyanarayana et_ a]_. , 1979; Davies et_ a_l_. , 1973; Gardner et a l . , 1975; and Gardner et a l . , 1977). These stud ies were of both adults and c h i l d r e n . Angelel i (1978) a l so examined exerc i se heart rates before and a f te r d ie tary supplementation in undernourished B r a z i l i a n adu l t s , and found s i g n i f i c a n t reduction in exerc i se heart rates a f te r supplementat ion. Two previous studies are not in accord with the resu l t s described above. Areskog and co-workers (19^9) found evidence that malnourished subjects performed better at work tests than t h e i r wel1-nourished counter- par t s , although th i s d i f fe rence was only pronounced when physical capa- c i t y was re lated to body weight. These authors concluded that perhaps d ietary requirements are set too high. Ferro-Luzzi and co-workers (1979) a l so found malnourished subjects performed better at work tests than we 11-nourished con t ro l s , and suggested that there may have been adapta- t ion to inadequate d ie t s such that work performance was not impaired. The present study would seem to add weight to the evidence that work performance can indeed be impaired in undernourished subjects as compared to wel1-nourished con t ro l s . Adaptation did not appear to be a f a c t o r i n t h i s s t u d y . Mean b l o o d l a c t i c a c i d l e v e l s a f t e r e x e r c i s e were s i g n i f i c a n t l y h i g h e r i n boi a - f r i a than w e l l - t o - d o s u b j e c t s . Maximum v a l u e s f o r change i n b l o o d l a c t i c a c i d w i t h e x e r c i s e were a l s o h i g h e r i n bo i a - f r i a than w e l l - t o - d o s u b j e c t s . B l o o d l a c t i c a c i d as a parameter o f p h y s i c a l work performance has o n l y o c c a s i o n a l l y been used i n r e s e a r c h on u n d e r n u t r i - t i o n . Gardner's group (1975.and 1977) i n two s e p a r a t e s t u d i e s found b l o o d l a c t i c a c i d l e v e l s i n res p o n s e t o e x e r c i s e were s i g n i f i c a n t l y e l e v a t e d i n i r o n - d e f i c i e n t s u b j e c t s . B l o o d l a c t i c a c i d l e v e l s r e p o r t e d i n t h e s e s t u d i e s were comparable t o t h o s e found i n the p r e s e n t s t u d y . In t he p r e s e n t s t u d y , t h e n , b o i a - f r i a s u b j e c t s e x h i b i t e d p o o r e r work performance as a s s e s s e d by p o s t - e x e r c i s e b l o o d l a c t i c a c i d l e v e l s than w e l l - t o - d o s u b j e c t s . For both groups o f s u b j e c t s , p o s t - e x e r c i s e b l o o d l a c t i c a c i d l e v e l s were s i g n i f i c a n t l y c o r r e l a t e d t o maximum h e a r t r a t e . However, the c o e f f i c i e n t o f d e t e r m i n a t i o n f o r t h i s r e l a t i o n s h i p was o n l y 11%, so i t i s d o u b t f u l t h a t the c o r r e l a t i o n was o f p r a c t i c a l s i g n i f i c a n c e . In summary, c o n s i d e r i n g both h e a r t r a t e and b l o o d l a c t i c a c i d as i n d i c a t o r s o f p h y s i c a l work p e r f o r m a n c e , work performance was found t o be i m p a i r e d i n b o i a - f r i a as compared t o w e l l - t o - d o s u b j e c t s when both groups were c o n f r o n t e d w i t h the same work t a s k . k. A s s o c i a t i o n Between N u t r i t i o n a l S t a t u s and P h y s i c a l Work Performance The a s s o c i a t i o n between n u t r i t i o n a l s t a t u s and p h y s i c a l work p e r f o r - mance was t e s t e d by d e t e r m i n i n g c o r r e l a t i o n c o e f f i c i e n t s between v a r i o u s i n d i c a t o r s o f n u t r i t i o n a l s t a t u s and each o f t h e f o l l o w i n g : maximum h e a r t r a t e ; change i n h e a r t r a t e ; p o s t - e x e r c i s e b l o o d l a c t i c a c i d ; and change i n b l o o d l a c t i c a c i d . 100 , . Maximum heart rate was s i g n i f i c a n t l y negat ively cor re la ted with: weight; height; upper-arm circumference; arm-muscle c ircumference; d ietary vitamin A, d ietary vitamin C; and d ietary r i b o f l a v i n . Change in heart rate was s i g n i f i c a n t l y negat ively cor re la ted wi th: weight; height; upper-arm circumference; arm-muscle c ircumference; serum albumin; and d ie tary vitamin A. Blood l a c t i c ac id leve ls were not found to be c o r r e - lated with any parameters of nu t r i t i ona l s ta tus . Although co r re l a t i on s may be s t a t i s t i c a l l y s i g n i f i c a n t , they have l i t t l e p rac t i ca l meaning i f c o e f f i c i e n t of determination is smal l . This was the case for several var iab les which were corre la ted with heart rates , inc lud ing : d ietary vitamin A; d ie tary vitamin C; d ie tary r i b o f l a v i n ; and serum albumin. On the other hand, several anthropometric var iab les were considerably more strongly cor re la ted to heart rates, inc lud ing : weight; height; arm circumference; and arm muscle c ircumference. The f ind ing that anthropometric var iab les were cor re la ted to physical work performance is in accordance with several previous studies which found p roduc t i v i t y , maximum aerobic power, and exerc i se heart rates to be s trong ly corre la ted to anthropometric var iab les (Heywood et_ aj_. , 1974; Barac-Nieto et_ aj_. , 1978; and Satyanarayana et_ aj_. , 1977 and 1979). The nu t r i t i ona l impl icat ions of th i s re l a t ionsh ip are that anthro- pometric var iab les are widely regarded to be indicators of long-term n u t r i t i o n a l s tatus. Indeed, i t has recent ly been suggested (Spurr et a l . , 1979) that because of co r re l a t i on s obtained between anthropometric var iab les and parameters of work performance, sub-maximal work tests may be useful as funct ional assessments of n u t r i t i o n a l s tatus. However, the fact that phys ica l work performance has been cor re la ted 101 to anthropometric parameters of n u t r i t i o n a l status does not mean that a causal re l a t i onsh ip has been demonstrated between undernutr i t ion and physical work performance. Consequently, the resu l ts of both th i s and previous studies must be interpreted caut ious l y . This and previous studies simply show that anthropometric ind icators of nu t r i t i ona l status and parameters of physical work performance appear to vary together. A further note is that i t does not appear from th i s study that e i the r prote in or iron status was corre la ted with physical work performance. Previous studies had found i r on -de f i c i ency anemia to co r re l a te with elevated exerc i se heart rates (Davies e_t a_l_. , 1973; Gardner e_t aj_., 1975; and Gardner et_ aj_. , 1977). However, in this study, neither d ietary nor b io - chemical assessment y ie lded evidence that severe protein or iron d e f i c - iencies were wi despread . ., It should be acknowledged that extrapo lat ion of the resu l t s of the present study to populations of B r a z i l i a n ch i ld ren other than the actual subjects studied can only be made very caut ious ly . This is because several factors were operant in th is study which may have biased the re su l t s . Because subjects were vo lunteers , people may have par t i c ipa ted who wanted medical a t tent ion or who had d i f f e r e n t d iets than those who did not. Chi ldren who were i l l and ch i ld ren who had dropped out of school did not p a r t i c i p a t e in th is study, which probably added b ias . F i n a l l y , the fact that sample se lec t i on was not random probably added b ias. These factors were unavoidable but nevertheless , they require acknowledgement. 102 CHAPTER VI SUMMARY AND CONCLUSIONS This study was designed and conducted to evaluate the nu t r i t i ona l status and physical work performance of ch i l d ren of B r a z i l i a n migrant workers in comparison with ch i ld ren from we l l - to -do B r a z i l i a n f am i l i e s , and to invest igate the re la t ionsh ip between nu t r i t i ona l status and physical work performance in these two groups of c h i l d r e n . Nutr i t iona l status was assessed by the fo l lowing means: soc io - economic and eco log ica l observations were made; 24-hour d iet reca l l i n t e r - views were used to assess d ietary intake; anthropometric measurements, inc luding height, weight, mid-uppei—arm circumference, and t r i ceps s k i n - fo ld thickness were taken; and hemoglobin, hematocrit, and serum tota l p ro te in , albumin, i ron , and percentage of t r a n s f e r r i n saturat ion were determined as biochemical ind icators of prote in and iron status. Physical work performance was assessed by measuring phys io log ica l responses, namely heart rate and blood l a c t i c ac id changes, to a bicycle-ergometer work te s t . The two groups of subjects were compared for a l l parameters of nu t r i t i ona l status and physical work performance. Then, i cor re la t ion ana lys i s was used to.determine whether parameters of physical work performance were associated with parameters of nu t r i t i ona l s ta tus . The basic f indings of th i s study were as fo l lows. Dietary assessment showed that migrant workers' ch i ld ren may have consumed i n s u f f i c i e n t intakes of the fo l lowing nu t r ien t s : energy, ca lc ium, thiamin, r i b o f l a v i n , n i a c i n , and vitamin C. The overa l l quant i t ie s of food consumed by these ch i ld ren were low, judging from c a l o r i c intakes 103 and from i n s p e c t i o n o f d i e t r e c a l l r e s u l t s . The b a s a l m i g r a n t worker f a m i l y d i e t a p p a r e n t l y c o n s i s t e d o f w h i t e r i c e and k i d n e y beans. I t appe a r e d p r o b a b l e t h a t p r o t e i n and i r o n , d e r i v e d m a i n l y from beans and r i c e , were consumed i n adequate amounts by b o i a - f r i a s u b j e c t s . In c o n t r a s t , w e l l - t o - d o c h i l d r e n s t u d i e d a p p a r e n t l y a t e a v a r i e d d i e t w i t h good r e p r e s e n t a t i o n from a l l f o o d groups i n c l u d i n g d a i r y p r o - d u c t s and animal p r o t e i n s o u r c e s . The w e l l - t o - d o s u b j e c t s appeared t o be a t l i t t l e r i s k o f low i n t a k e f o r any n u t r i e n t w i t h t h e p o s s i b l e e x c e p t i o n o f n i a c i n . G e n e r a l l y , t h e o v e r a l l q u a n t i t i e s o f food consumed by t h e s e c h i l d r e n a l s o appeared t o be adequate. A n t h r o p o m e t r i c assessment showed t h a t n u t r i t i o n a l d e f i c i e n c i e s o f boi a - f r i a s u b j e c t s were m a n i f e s t e d i n low body w e i g h t s f o r age and f o r h e i g h t , and low body f a t r e s e r v e s as e v i d e n c e d by e x t r e m e l y low v a l u e s f o r t r i c e p s s k i n f o l d t h i c k n e s s . The w e l l - t o - d o s u b j e c t s exceeded American s t a n d a r d s f o r a l l a n t h r o p o m e t r i c parameters measured. B i o c h e m i c a l assessment o f p r o t e i n s t a t u s i n both groups o f c h i l d r e n showed no e v i d e n c e o f o v e r t d e f i c i e n c i e s . However, both e a r l y - and l a t e - s t a g e i n d i c a t o r s o f i r o n d e f i c i e n c y s u g g e s t e d t h a t some b o i a - f r i a s u b j e c t s may have had m a r g i n a l i r o n s t a t u s . The w e l l - t o - d o c h i l d r e n p r e s e n t e d normal v a l u e s f o r a l l b i o c h e m i c a l i n d i c a t o r s o f i r o n s t a t u s t h a t were a s s e s s e d . P h y s i c a l work performance was found t o be i m p a i r e d i n m i g r a n t w o r k e r s ' c h i l d r e n as compared t o w e l l - t o - d o c h i l d r e n i n t h i s s t u d y . E x e r c i s e h e a r t r a t e s and p o s t - e x e r c i s e b l o o d l a c t i c a c i d l e v e l s were both more e l e v a t e d i n b o i a - f r i a than i n w e l l - t o - d o s u b j e c t s . P h y s i c a l work performance as i n d i c a t e d by change i n h e a r t r a t e d u r i n g e x e r c i s e was found t o be s i g n i f i c a n t l y c o r r e l a t e d w i t h a n t h r o p o m e t r i c 104 parameters of nu t r i t i ona l status in the subjects s tud ied. This co r re l a t i on was not demonstrated for other parameters of nu t r i t i ona l s tatus. Neither was a c o r r e l a t i o n demonstrated between parameters of nu t r i t i ona l status and physical work performance as indicated by blood l a c t i c ac id leve l s during exerc i se . The overa l l s i gn i f i c ance of the f indings of th i s study appears to be that undernutr i t ion did indeed ex i s t among these migrant workers' c h i l d r e n . In contras t , undernutr i t ion was not found .in we l l - to -do ch i ld ren in th i s study. In add i t i on , funct iona l assessment showed that when confronted with the same work task, b o i a - f r i a s performed more poorly than we l l - to -do ch iIdren . A b r i e f summary of the l i v i n g condit ions and health status of the two groups was made as an adjunct to this study. L iv ing condit ions in the fayela or slum area of Ribeirao Preto where most migrant workers l i ved were genera l ly impoverished, crowded, and devoid of conveniences- such as indoor running water, e l e c t r i c i t y , or sewage f a c i l i t i e s . In cont ras t , the we l l - to -do ch i ld ren l i ved in an area where the p i c ture was much more appeal ing. Spacious homes, a t t r a c t i v e s treets and gardens, and f u l l amenities such as e l e c t r i c i t y and indoor plumbing were the ru le . Incomes of we l l - to -do fami l ie s were estimated to be sub- s t a n t i a l l y higher than those of migrant worker f a m i l i e s . Migrant workers' ch i ld ren a l so presented a much higher incidence of bronchial in fec t ions and card iac anomalies than did we l l - to -do c h i l d r e n . This was in add i t ion to the p a r a s i t i c i n fe s ta t i on that is known to be endemic among migrant workers in th i s area. Thus i t appears that disease and in fec t ion ex i s t synerg ist ica11y with undernutr i t ion among bo i a - f r i as. To extend socio-economic ana lys i s beyond the simple observations 105 made in th i s study, i t appears that there are factors in the l i ves of migrant worker fami l ie s which deeply aggravate any nu t r i t i ona l problems these people may have. Indeed, the existence of these factors probably precludes the so lu t ion of nu t r i t i on problems in i s o l a t i o n . The l i t any of these factors is long: impossibly low wages that are ravaged by i n f l a - t i o n ; jobs that o f f e r l i t t l e hope of enjoyment or upward mob i l i t y ; f r e - quent unemployment without provis ions for soc ia l s ecu r i t y ; endemic d i s - ease without access ib le medical care; i l l i t e r a c y ; and squal id l i v i n g con- d i t i ons. Another important fac tor is the mental i ty of poverty. These migrant workers see no way to improve the condit ions of the i r l i ves because they have always been ob jec t s , cogs in the wheels of the B r a z i l i a n economy. P o s s i b l i t i e s for changing the i r s i t ua t i on l i e in the awakening of the i r sense of the i r own humanity and the i r a b i l i t i e s for s e l f - d e t e r - mination such that they themselves can improve the condit ions of the i r l i v e s . This process could be aided by the development of thoughtful programs to a l l e v i a t e n u t r i t i o n problems through education and income ass i s tance. As w e l l , programs to improve housing, s a n i t a t i o n , educat ion, and health care would play an important transformational ro le . The resu l t s of th i s study are prof fered in the hope that they w i l l add weight to the already considerable evidence that n u t r i t i o n problems ex i s t among migrant worker fami1 ies in B r a z i l . It is a l so hoped that the re l a t i onsh ip that was demonstrated here between undernutr i t ion and impaired work performance may fuel economic j u s t i f i c a t i o n s for improving n u t r i t i o n a l condit ions among B r a z i l i a n a g r i c u l t u r a l labourers and the i r c h i l d r e n . To conclude on a sombre note, enough is now known about nu t r i t i ona l problems of people such as these migrant worker f a m i l i e s . 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