Roles of various dietary fiber sources on improvement blood lipid profiles of hypercholesterolemic mice

Abstract

Dietary fiber is widely used as a functional food and recommended to reduce blood lipid levels to prevent hypercholesterolemia. Agar, carrageenan, and rice bran, are examples of foods with high fiber content. These experiments were designed to study the effects of agar, carrageenan, and rice bran supplementations on blood lipid profiles of hypercholesterolemic male mice. The study was divided into three experiments. The first experiment was designed to formulate diet that could induce hypercholesterolemia in male mice as animal models in this study. The second experiment was designed to improve blood lipid profiles of hypercholesterolemic male mice by using agar, carrageenan, and rice bran as sources of dietary fiber. The third experiment was designed to study the effectiveness of dietary fiber as compared to standard drugs in lowering blood lipid profiles in hypercholesterolemic male mice. The experiments were conducted at Faculty of Veteriner Medicine, Bogor Agricultural University and Physiology Laboratory, Indonesia University of Education, in January 2011 until March 2012. The parameters measured were body weight, cholesterol concentrations in serum, liver, and feces, serum triglyceride, cholesterol high density lipoprotein (HD-c), cholesterol low density lipoprotein (LDL-c), and glucose concentrations. The first experiment showed that feeding a high-fat diet (12%) for 30 days could produce hypercholesterolemic conditions in male mice. The second experiment showed that supplementation of 18% agar, 46% carrageenan, and 57% rice bran (equivalent to insoluble dietary fiber content of 14%) in hypercholesterolemic mice fed with hypercholesterolemic diets could improve blood lipid profiles. Carrageenan as a source of dietary fiber showed the best effect on improvement of blood lipid profile in hypercholesterolemic male mice as compared to agar and rice bran, as indicated by the lower serum total cholesterol and triglyceride concentrations, higher serum HDL-c concentrations, and higher removal of cholesterol in feces. The third experiment showed that the effects of dietary fiber supplementation by agar, carrageenan and rice bran on lowering blood lipid profiles in hypercholesterolemic mice were lower than those of simvastatin and atorvastatin. Carrageenan as a source of functional dietary fiber had a potenstial to decrease LDL-c concentration, to increase HDL-c concentration, and to increase fecal cholesterol excretion with the final reduction in total serum cholesterol concentrations similar to simvastatin and atorvastatin. It was concluded that supplementation of agar, carragenan, and rice bran as a source of dietary fiber decreased body weight, serum and liver cholesterol concentrations, serum triglyceride and LDL-c concentrations, but increased serum HDL-c concentrations, and increased cholesterol excretion through feces, without a significant effect on blood glucose consentrations. Agar, carrageenan, and rice bran supplementation as sources of dietary fibers could improve lipid profiles in hypercholesterolemic mice.