UBC Theses and Dissertations
Self-reported lactose intolerance : subtitle an exploratory study of knowledge, attitudes, diagnostic characteristics and calcium intake Lovelace, Heather Yvonne
Numerous studies indicate that more people claim to be lactose intolerant than there actually are, which suggests widespread misconceptions exist. However, there has been little research to assess how people decide that they are lactose intolerant, and the nutritional implications of this perception. Perceived lactose intolerance may be just as important as true lactose intolerance since dietary changes may ensue, possibly compromising among other nutrients, calcium intake and increasing osteoporosis risk. The objective of this study was to assess calcium intake of individuals with self-reported lactose intolerance. Participants, recruited through newspaper advertisements, completed a food frequency questionnaire to estimate calcium intake from food and supplementary sources. Questions to elicit information on diagnosis, symptom severity, and demographics were included. Furthermore, knowledge, attitudes and dairy product intake behaviours were assessed using scales. All data were analyzed using the Statistical Package for the Social Sciences (SPSS, version 10) statistical environment, using descriptive statistics, chi-square or Fisher's Exact tests, t-tests and Analysis of Variance. A total of 159 participants completed and returned questionnaires (84% response rate). Respondents were 47 ± 15 yrs of age; 72% female and 28% male; 67% Caucasian; and >53.8% had self-diagnosed their lactose intolerance. Of those with physicians involved in diagnosis, 9.7% had confirmable diagnoses by reliable testing methods. Knowledge scores indicated good knowledge of lactose intolerance by participants. Attitudes towards dairy products were more negative among participants than among other British Columbians, and other Canadians when compared to population studies. Fluid milk caused discomfort in 67% of study participants. Mean estimated food calcium intake was 591 ± 382 mg/d. Estimates were lower for those who excluded milk, cheese or yogurt. There were no significant differences by sex or age, nor was there an age-by-sex interaction. Only 11.5% of participants met their age-appropriate Adequate Intake (AI) levels from food calcium sources alone. In comparison to large population studies (Alaimo et al., 1994) participants in this investigation had lower estimates of calcium intake from food sources alone. Thus, health professionals involved in diagnosis of lactose intolerance should be encouraged to discuss calcium needs, food sources of calcium and calcium supplementation with those self-reporting lactose intolerance to promote individuals' ability to meet AI levels.
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