Influence of Medium-chain Triglyceride (MCT) on Cholesterol Metabolism in Rats

Abstract

Medium-chain triglyceride (MCT) is a liquid, saturated fat composed almost entirely of triglycerides of C8 and C10 fatty acids. The effect of MCT on serum and liver cholesterol levels of normal and cholesterol-fed rats and upon hepatic lipogenesis in rats was compared with coconut oil and corn oil. Normal rats fed 20% MCT exhibited lower serum and liver cholesterol levels than did control rats or rats fed 20% coconut oil or corn oil. In rats fed 2% cholesterol and 0.5% cholic acid and 20% MCT, serum cholesterol levels were about one-half of levels observed in rats fed cholesterol-cholic acid and either coconut or corn oil. Liver cholesterol levels in the MCT-fed rats were about 65% of levels in the other 2 groups. The serum β-lipoprotein cholesterol was elevated to the same extent in all 3 groups. The α-/β-lipoprotein cholesterol ratio is 0.10. When hypercholesteremic rats were fed cholesterol-free diets containing 20% of MCT, coconut or corn oil for 2 weeks, serum and liver cholesterol levels decreased at the same rate in all 3 groups. In vivo hepatic lipogenesis from acetate in MCT-fed rats was lower than that observed in rats fed corn oil and equal to that observed in rats fed coconut oil. Fatty acid synthesis was significantly higher in the MCT group. In liver slices, cholesterol synthesis from acetate was lower in rats fed coconut oil than it was in the MCT or corn oil groups. When mevalonate is the precursor, cholesterogenesis was equal in all 3 groups. Fatty acid synthesis was highest in liver slices of MCT-fed rats.