Dietary fiber, weight gain, and cardiovascular disease risk factors in young adults

Context Dietary composition may affect insulin secretion, and high insulin levels, in turn, may increase the risk for cardiovascular disease (CVD). Objective To examine the role of fiber consumption and its association with insulin levels, weight gain, and other CVD risk factors compared with othe r major dietary components. Design and Setting The Coronary Artery Risk Development in Young Adults (CA RDIA) Study, a multicenter population-based cohort study of the change in C VD risk factors over 10 years (1985-1986 to 1995-1996) in Birmingham, Ala; Chicago, III; Minneapolis, Minn; and Oakland, Calif. Participants A total of 2909 healthy black and white adults, 18 to 30 years of age at enrollment. Main Outcome Measures Body weight. insulin levels, and other CVD risk facto rs at year 10, adjusted for baseline values. Results After adjustment for potential confounding factors, dietary fiber s howed linear associations from lowest to highest quintiles of intake with t he following. body weight (whites: 174.8-166.7 lb [78.3-75.0 kg], P < .001; blacks: 185.6-177.6 lb [83.5-79.9 kg], P = .001), waist-to-hip ratio (whit es, 0.813-0.801, P = .004; blacks: 0.809-0.799, P = .05), fasting insulin a djusted for body mass index (whites: 77.8-72.2 pmol/L [11.2-10.4 mu U/mL], P = .007; blacks: 92.4-82.6 pmol/L [13.3-11.9 mu U/mL], P = .01) and 2-hour postglucose insulin adjusted for body mass index (whites: 261.1-234.7 pmol /L [37.6-33.8 mu U/mL], P = .03; blacks: 370.2-259.7 pmol/L [53.3-37.4 mu U /m L], P < .001). Fiber was also associated with blood pressure and levels of triglyceride, high-density lipoprotein cholesterol, low-density lipoprot ein cholesterol, and fibrinogen; these associations were substantially atte nuated by adjustment for fasting insulin level. In comparison with fiber, i ntake of fat, carbohydrate, and protein had inconsistent or weak associatio ns with all CVD risk factors. Conclusions Fiber consumption predicted insulin levels, weight gain, and ot her CVD risk factors more strongly than did total or saturated fat consumpt ion. High-fiber diets may protect against obesity and CVD by lowering insul in levels.