Objective: To examine prospectively the relationship between dietary fiber and risk of coronary heart disease.
Design: Cohort study.
Setting: In 1986, a total of 43,757 US male health professionals 40 to 75 years of age and free from diagnosed cardiovascular disease and diabetes completed a detailed 131-item dietary questionnaire used to measure usual intake of total dietary fiber and specific food sources of fiber.
Main outcome measure: Fatal and nonfatal myocardial infarction (MI).
Results: During 6 years of follow-up, we documented 734 cases of MI (229 were fatal coronary heart disease). The age-adjusted relative risk (RR) for total MI was 0.59 (95% confidence interval [CI], 0.46 to 0.76) among men in the highest quintile of total dietary fiber intake (median, 28.9 g/d) compared with men in the lowest quartile (median, 12.4 g/d). The inverse association was strongest for fatal coronary disease (RR, 0.45; 95% CI, 0.28 to 0.72). After controlling for smoking, physical activity and other known nondietary cardiovascular risk factors, dietary saturated fat, vitamin E, total energy intake, and alcohol intake, the RRs were only modestly attenuated. A 10-g increase in total dietary fiber corresponded to an RR for total MI of 0.81 (95% CI, 0.70 to 0.93). Within the three main food contributors to total fiber intake (vegetable, fruit, and cereal), cereal fiber was most strongly associated with a reduced risk of total MI (RR, 0.71; 95% CI, 0.55 to 0.91 for each 10-g increase in cereal fiber per day).
Conclusions: Our results suggest an inverse association between fiber intake and MI. These results support current national dietary guidelines to increase dietary fiber intake and suggest that fiber, independent of fat intake, is an important dietary component for the prevention of coronary disease.