DIETARY FIBER, THE EVOLUTION OF THE HUMAN DIET AND CORONARY HEART-DISEASE

Speculation on the evolution of the human diet together with comparati ve studies with the diet of other primates suggest that the human gast rointestinal tract and metabolism are adapted to high fiber diets. Epi demiological studies support a negative association between dietary fi ber intake and risk of coronary heart disease (CHD). For the mast part , the association has been with insoluble fiber, especially wheat bran . However, viscous fiber sources are likely to play a role since they reduce lipid risk factors for CHD including total and low-density-lipo protein cholesterol and apolipoprotein B by increasing fecal bile acid losses. In addition, soluble fiber may reduce the rate of nutrient ab sorption so altering chylomicron synthesis and reducing postprandial g lucose and insulin levels and other risk factors for CHD. There is als o evidence that some insoluble fibers might alter serum lipids and imp rove carbohydrate tolerance but these phenomena need to be confirmed a nd other mechanisms explored including improved clotting and thromboly tic factors and increased antioxidant status. Epidemiology, clinical a nd laboratory studies support increased consumption of high fiber food s as part of the strategy to reduce the risk of CHD. (C) 1998 Elsevier Science Inc.