ABSTRACT
A number of animal studies have demonstrated that rats fed controlled diets supplemented with psyllium fiber experience a significant decrease in serum cholesterol levels. The physiological attributes of fiber largely depend upon their physical characteristics, namely the molecular design and solubility. Although the physiological influences of dietary fibers were once thought to be limited to the intestinal lumen, which is anatomically exterior, newer evidence suggests that derivatives of intestinal fiber metabolism can influence more internal operations as well. Lignin stands alone as a fiber in that it is not a carbohydrate; yet it is considered an insoluble dietary fiber. The US Food and Drug Administration allows food manufacturers to use certain health claims related to the link between dietary fiber and a reduced risk of heart disease. The well-known Framingham Study was among the first to establish a statistical relationship between serum lipoproteins and coronary heart disease.
