Mechanism of the Cholesterol-depressing Effect of Pectin in the Cholesterol-fed Rat

Abstract

The mechanisms by which dietary pectin lowers plasma and liver cholesterol levels in cholesterol-fed rats were studied. Pectin feeding increased fecal bile acid excretion in cholesterol-fed rats. In vitro studies with inverted intestinal sacs demonstrated that pectin decreased taurocholic acid transport by approximately 50%. Rats responded to dietary pectin and cholestyramine, a known inhibitor of bile acid absorption, similarly. Cholesterol-4-¹⁴C absorption was somewhat depressed by dietary pectin as evidenced by fecal radioactive cholesterol excretion and deposition of cholesterol-4-¹⁴C in liver. The effect of pectin on plasma and liver cholesterol was not altered by dietary succinylsulfathiazole. These data are interpreted to suggest that the hypocholesterolemic effects of pectin are not mediated by an alteration of the intestinal microflora. The results of this study indicate that pectin lowers plasma and liver cholesterol levels in cholesterol-fed rats primarily by inhibiting bile acid absorption and also by reducing cholesterol absorption.