Lack of effect of linoleic acid on the high-density-lipoprotein-cholesterol fraction of plasma lipoproteins.

Low-fat, natural diets were fed to 11 middle-aged, healthy male subjects for two 40-d periods to determine effects on plasma lipoproteins. The diets were designed to maintain saturated and monounsaturated fatty acids at 10 en% and linoleic acid (LA) at 3.8 and 10.8 en%. When compared with baseline concentrations, total cholesterol decreased 10% at the end of the lower LA diet and 15% at the end of the higher LA diet. Low-density-lipoprotein cholesterol (LDL-C) decreased 18% and 22%, respectively, during the same periods. Plasma high-density-lipoprotein cholesterol (HDL-C) at the end of each dietary period was not significantly different but the midpoint values were lower by 12.5% on the lower LA diet and 7.3% on the higher LA diet. Apolipoprotein B decreased 27% at the end of the lower LA diet and 37% at the end of the higher LA diet whereas apolipoprotein A-I increased 18% and 24%, respectively. HDL-C was not reduced by dietary LA over a 6-wk period.