Dietary fiber, the evolution of the human diet and coronary heart disease

Speculation on the evolution of the human diet together with comparative studies with the diet of other primates suggest that the human gastrointestinal tract and metabolism are adapted to high fiber diets. Epidemiological studies support a negative association between dietary fiber intake and risk of coronary heart diseases (CHD). For the most 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 rink factors for CHD including total and low-density-lipoprotein cholesterol and apolipoprotein B by increasing fecal bile acid losses. In addition, soluble fiber may reduce the rate of nutrient absorption so altering chylomicron synthesis and reducing postprandial glucose and insulin levels and other risk factors for CHD. There is also evidence that soma insoluble fibers might alter serum lipids and improve carbohydrate tolerance but these phenomena need to be confirmed and other mechanisms explored including improved clothing and thrombolytic factors and increased antioxidant status. Epidemiology, clinical and laboratory studies support increased consumption of high fiber foods as part of the strategy to reduce the risk of CHD.