OLEIC-ACID RICH DIET PROTECTS AGAINST THE OXIDATIVE MODIFICATION OF HIGH-DENSITY-LIPOPROTEIN

Oxidative modifications of lipoproteins could contribute to the develo pment of atherosclerosis, but the influence of dietary fats on high de nsity lipoprotein (HDL) oxidative modification is unknown. This study was designed to determine whether a diet rich in oleic acid could modu late the oxidative modification of HDL(3). Twenty two healthy men were randomly placed on a 32-wk crossover study of an oleic acid rich diet supplied by a variant of sunflower oil vs a linoleic acid rich diet p rovided by conventional sunflower oil. Plasma HDL(3) obtained after th e diet rich in oleic acid showed a significantly higher oleic acid con tent in the phospholipid than lipoprotein isolated after the linoleic acid rich diet, HDL(3) isolated after the oleic acid rich diet had low er values of thiobarbituric acid reactive substances (TBARS) than HDL( 3) obtained after the linoleic acid rich diet both for native (mean +/ - SE; 0.24 +/- 0.02 vs 0.42 +/- 0.08 nmol MDA/mg protein; p < 0.01) an d copper oxidized HDL(3) (0.75 +/- 0.06 vs 0.95 +/- 0.07 nmol MDA/mg p rotein; p < 0.01). Indeed, TBARS for native HDL(3) were negatively cor related with the oleic acid to linoleic acid ratio and positively with the percentage of linoleic acid in their phospholipids. Interestingly , HDL(3) after both diets had similar antioxidant vitamins A and E con tent. HDL(3) overall composition and fluidity were similar after the t wo diets, Moreover, HDL(3) obtained after both diets produced identica l [H-3] free cholesterol efflux from human monocyte-derived macrophage s (29%) and fibroblasts (26%). In conclusion, HDL(3) rich in oleic aci d was less easily oxidized regardless of the content of antioxidants s uch as vitamins A and E. Therefore, dietary monounsaturated fatty acid prevent the oxidative modification of lipoproteins. Copyright (C) 199 7 Elsevier Science Inc.