The Effects of Dietary Fatty Acids on LDL-cholesterol Metabolism

Abstract

Increases in serum VLDL- and LDL-cholesterol levels and hepatic VLDL-cholesterol secretion were observed in animals fed a diet enriched with 0.1 cholesterol in comparison with control animals.
Addition of dietary palmitic acid accelerated the effect of cholesterol on serum VLDL- and LDL-cholesterol levels and hepatic VLDL-cholesterol secretion.
Dietary linoleic acid accelerated the effect of cholesterol on hepatic VLDL-cholesterol secretion and diminished the effect of cholesterol on the serum LDL-cholesterol level.
Hepatic LDL-receptor activity was suppressed by a control diet containing 0.05% cholesterol, and no further suppression was induced by a diet enriched with 0.1% cholesterol with or without 5% palmitic acid. However, dietary linoleic acid diminished the effect of cholesterol on the suppression of hepatic LDL-receptor activity.
These results suggest that by accelerating hepatic VLDL-cholesterol secretion, dietary palmitic acid augments the effect of cholesterol in elevating the serum LDL-cholesterol level and that dietary linoleic acid diminishes the elevation of serum LDL-cholesterol level by cholesterol by preventing the suppression of hepatic LDL-receptor activity induced by cholesterol. However, the precise mechanism of dietary fatty acids on the regulation of lipoprotein metabolism was not clear.