Effects of Dietary Calcium upon Lipid Metabolism in Mature Male Rats Fed Beef Tallow

Abstract

In an attempt to elucidate the hypocholesterolemic and hypotriglyceridemic action of dietary calcium, 24 mature male Holtzman strain albino rats were fed a corn-soya ration containing 18% added beef tallow and 2% added cholesterol for 21 days. Dietary calcium was varied at 0.08, 0.2 and 1.2% of diet. Blood lipids decreased with increasing dietary calcium, the major decrease occurring at the 0.2% calcium level. Some tissue lipids decreased; none increased. Fecal lipids did not significantly increase at the 0.2% calcium level, but did at the 1.2% level. Fecal fatty acids became progressively more saturated with increasing calcium intake, but the preferential excretion of saturated fatty acids did not appear to be sufficient to alter significantly the blood fatty acids. Fecal bile acids significantly increased at the 0.2% calcium level, with no additional increase at the 1.2% calcium level. These results suggest that the lowering of blood cholesterol by increase in dietary calcium is mediated in part by increased excretion of bile acids.