Chapter 6 - Dietary Fiber and Risk of Cardiovascular Diseases

Abstract

Mortality and morbidity due to heart diseases is decreasing in developed countries due to healthy diet and lifestyle, whereas in developing countries, it is rapidly increasing due to unhealthy diets and lifestyle. Healthy diets are rich in plant foods and majority of the plant foods are rich in fiber. Vegetables, whole grains, fruits, and legumes are rich sources of fibers. Soluble fibers have been considered more useful compared to insoluble fibers. Dietary fibers are known to have hypoglycemic, hypocholesterolemic, antioxidant, antiinflammatory, and antihypertensive effects indicating that fiber intake may be protective against cardiovascular diseases (CVDs), coronary artery disease (CAD), stroke, and hypertension, as well as diabetes. In a meta-analysis, 22 cohort study publications met inclusion criteria. Total dietary fiber intake, fiber subtypes, or fiber from food sources and primary events of CVDs or CAD were considered important. Total dietary fiber intake was inversely associated with risk of CVD including CAD. Observed heterogeneity between pooled studies for CVD and CAD were apparent. Insoluble fiber and fiber from cereal and vegetable sources were inversely associated with risk of CAD and CVD. Fruit fiber intake as part of Mediterranean style diet was also inversely associated with risk of CVD. It is possible that increased consumption of dietary fiber may be associated with a lower risk of both CVD and CAD. These results support the general recommendations to increase fiber intake for prevention of CVDs. The mechanism could be that fiber inhibit the absorption of fat from the gut but recently dietary fiber has been demonstrated to be beneficial for gut microbiome. The differing strengths of association by fiber type or source highlight the need for a better understanding of the mode of action of fiber components and the effects of fiber on other targets, which indirectly control CVDs.