Effect of dietary fats on serum and aortic lipid levels of mice fed a highcholesterol diet: A distinct correlation between linoleic acid intake and the lipid changes

Abstract

The effects of dietary linoleic acid on serum lipids, lipid peroxides and aortic cholesterol were studied in mice fed a purified diet enriched with 5% cholesterol for a period of 14 weeks. The diet was supplemented with 10% coconut oil (Group I), lard (Group II), corn oil (Group III) or linoleic acid (Group IV) to give various levels of linoleic acid. After 4 to 12 weeks, the increment of serum total cholesterol was retained in the following order: group IV>III>II>I, which was the same order as the linoleic acid content in the diet. At week 14, the levels of serum free and esterified cholesterol, HDL-cholesterol, triglycerides and phospholipids were highest in group IV and lowest in group I. The serum lipid peroxide level was higher in the order of group IV>III>II>I. The ester ratio of cholesterol, the atherogenic index and LCAT activity were not significantly different among the four groups. Gallstone formation was markedly observed with higher dietary linoleic acid intake. Aortic cholesterol levels also increased in the same order as the dietary linoleic acid level: group IV>III>II>I. There were significant positive correlations between the aortic cholesterol level and all the serum lipid levels, and also the lipid peroxide level. All these findings indicate that under hypercholesterolemic conditions, excess dietary linoleic acid can increase serum lipids and lipid peroxide levels, resulting in lipid deposition in the aorta. These metabolic alterations may adversely influence atherogenesis.