Effects of Saturated and Unsaturated Fat on Cholesterol Metabolism in the Rat

Abstract

Rats fed a diet containing 20% corn oil had lower serum cholesterol than those fed with 20% coconut oil. Both oils tended to elevate serum cholesterol above that found on control diet. Corn oil, but not coconut oil, markedly increased the content of esterified cholesterol in liver. Sterol-free linoleic acid also caused a similar effect. This demonstrates that the vegetable sterols are not responsible for this change in liver composition. The rate of incorporation of 1-CI4 -acetate and T2O into cholesterol of liver, serum and adrenals was significantly higher in rats on corn oil than in the others. It is concluded, since the animals were in a steady state, that the rate of cholesterol breakdown is also increased on feeding corn oil. It is suggested that unsaturated oils lower serum cholesterol by affecting its partition between tissues and serum.