THE EFFECT OF EARLY FEEDING ON HUMAN CHOLESTEROLSYNTHESIS AT FOUR MONTHS OF AGEbyJanet L. BulaniB. Sc., University of Saskatchewan, 1989A THESIS SUBMITTED IN PARTIAL FULFILMENT OFTHE REQUTREMENTS FOR THE DEGREE OFMASTER OF SCIENCEinTHE FACULTY OF GRADUATE STUDIES(School of Family and Nutritional Sciences)We accept this thesis as conformingto the required standardTHE UMVERSITY OF BRITISH COLUMBIAMarch, 1994© Janet L. BulaniIn presenting this thesis in partial fulfilment of the requirements for an advanceddegree at the University of British Columbia, I agree that the Library shall make itfreely available for reference and study. I further agree that permission for extensivecopying of this thesis for scholarly purposes may be granted by the head of mydepartment or by his or her representatives. It is understood that copying orpublication of this thesis for financial gain shall not be allowed without my writtenpermission.(Signature)Department of1Jj L77d j9Schneo0The University of British ColumbiaVancouver, CanadaDate 4CJi c2DE.6 (2188)ABSTRACTHuman milk is relatively high in cholesterol compared with infant formula (10-15 mg/dLversus 0-1.1 mgldL respectively). The high intake of cholesterol by breast-fed infants ascompared to those fed formula has been shown in the past to result in high circulating levels ofcholesterol. It is presently hypothesized that this abundance of cholesterol in the diet inhibitsendogenous cholesterol synthesis, resulting in the low rates of cholesterol synthesis seen in breast-fed infants, as opposed to formula-fed infants. Continual suppression of cholesterol synthesis ininfancy may render the breast-fed infant less able to synthesize cholesterol as an adult. Ideally,when challenged with a high cholesterol diet as an adult, it would be preferable for the body tolimit its own synthesis of cholesterol, in order to counterbalance the increased availability ofcholesterol in the diet. Infants never having had to make their own cholesterol would have anadvantage over those whose metabolism had been imprinted at a young age to synthesizecholesterol. This latter group may not have the same capacity to downregulate endogenouscholesterol synthesis as adults.Three groups of infants were used to examine the effect of cholesterol feeding in the first fourmonths of life on serum lipids and endogenous cholesterol synthesis. Group one was breast-fed.Group two was fed a regular commercially available infant formula. Group three was fed thesame formula enriched with cholesterol at a level similar to that found in breast milk (13 mgldL).There was no difference in serum lipids between breast-fed and formula-fed infants, nor betweenthe two different formula groups. Total-cholesterol was 4.33± 0.85, 3.65±0.40, and 3.75±1.06mmoWL for the breast-fed, modified formula-fed, and regular formula-fed respectively. LDLcholesterol was 2.18±0.81, 1.43±0.56, and 1.64±0,72 mmol/L respectively. HDL-cholesteroliilevels were 1.17± 0.26, 1.10±0.30, 1.07±0.14 mmol/L respectively. Triglyceride levels were4.90±1.60, 5.61±2.48, and 5.15±2.20 mmol/L respectively. Fractional synthetic rates ofcholesterol (FSR) were significantly (p