The effect of psyllium, sugar beet, barley bran, and oat bran containing diets on serum cholesterol, and liver lipids, in rats

Abstract

The effects of feeding four dietary fibers (psyllium, sugar beet, barley bran and oat bran) on serum HDL, VLDL+LDL, total, HDL/LDL, liver lipid, and liver cholesterol were examined. Rats were divided into ten groups of six each, and were given ad libitum access to purified diets containing either no fiber (control), or 10% psyllium, sugar beet, barley bran or oat bran, each in the presence or absence of dietary cholesterol. Three rats from each group were sacrificed at the end of 4 and 8 weeks, to determine the length of time taken for the hypocholesterolemic effect (if any) to show up. ANOVA was run on a SAS GLM procedure to statistically analyse data. No significant differences were seen on feed intake, weight gain, and feed efficiency ratio of the animals fed various diets. The psyllium diet (in presence of dietary cholesterol) not only lowered serum LDL (P<0.01), liver cholesterol (P<0.01), and liver lipid (P<0.01), but also raised the HDL (P<0.10), and HDL/LDL cholesterol ratio (P<0.01). Sugar beet, barley bran and oat bran failed to show a clearly defined cholesterol lowering effect. Results of this study indicate that among the fibers examined, psyllium was the most effective. The mechanism of the hypocholesterolemic action of psyllium may involve: 1) increased fecal excretion of bile acids, 2) effect of short chain fatty acids produced by fermentation, and/or 3) changes in the rate or amount of nutrients absorbed from the small intestine.