Dietary fiber and risk of coronary heart diseases

Abstract

Dietary fiber is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers can be grouped generally by their solubility, viscosity, and fermentation, which affect how fibers are processed in the body. Dietary fiber has two main components: soluble fiber and insoluble fiber, which are components of plant foods, such as legumes, whole grains and cereals, vegetables, fruits, and nuts or seeds. Consumption of cereals, vegetable and fruit may lower the risk of coronary heart disease. Coronary heart disease involves the reduction of blood flow to the heart muscle due to build-up of plaque on the arteries of the heart. Dietary fiber makes three primary contributions: bulking, viscosity and fermentation. The bulking effect of some fibers reduces constipation and the risk of colon disease because they absorb water, which increases bulking and promotes regularity. Viscosity effects on fibers reduce the absorption of cholesterol and other nutrients because of the formation of gels that attenuate postprandial blood glucose and lipid rises. The formation of gels also slows gastric emptying, maintaining levels of satiety and contributing towards less weight gain. In the fermentation process, the bacteria GIT helps to digest fiber through a process of microbial fermentation to generate short chain fatty acids like acetate, propionate and butyrate. Butyrate binds to G-protein coupled receptors on the brush borders of intestinal lining and trigger a signal cascade that release GLP-1 and PYY. These peptides behave like hormones to trigger satiety. One of the reasons for eating fiber rich foods is because they promote satiety and prevent uncontrollable quest for food. People that eat food low in fiber experience over feeding issues. When people over eat they consume more calories leading to weight gain and that contributes to obesity. Obesity is the accumulation of fats in fat tissues. Excess fats are converted to cholesterol (LDL) which accumulates on the walls of the arteries and prevent the flow of blood to the heart. This is prevented when an individual consumes foods rich in fiber.