Effects of oleate-rich and linoleate-rich diets on the susceptibility of low density lipoprotein to oxidative modification in mildly hypercholesterolemic subjects.

Abstract

We report the results of feeding oleate-or linoleate-enriched diets for 8 wk to mildly hypercholesterolemic subjects and the resulting alterations in composition and functional properties of their plasma LDL and HDL. LDL isolated from subjects on oleate-enriched diets was less susceptible to copper-mediated oxidation, as measured by conjugated diene and lipid peroxide formation, and less susceptible to LDL-protein modification, as evidenced by reduced LDL macrophage degradation after copper-or endothelial cell-induced oxidation. For all subjects, the percentage of 18:2 in LDL correlated strongly with the extent of conjugated diene formation (r = 0.89, P < 0.01) and macrophage degradation (r = 0.71, P < 0.01). Oxidation of LDL led to initial rapid depletion of unsaturated fatty acids in phospholipids followed by extensive loss of unsaturated fatty acids in cholesteryl esters and triglycerides. Changes in HDL fatty acid composition also occurred. However, HDL from both dietary groups retained its ability to inhibit oxidative modification of LDL. This study demonstrates that alterations in dietary fatty acid composition can effectively alter the fatty acid distribution of LDL and HDL in hypercholesterolemic subjects and that susceptibility to LDL oxidation is altered by these changes. Substitution of monounsaturated (rather than polyunsaturated) fatty acids for saturated fatty acids in the diet might be preferable for the prevention of atherosclerosis. (J. Clin. Invest. 1993. 91:668-676.)

Oxidation of low-density lipoprotein in NIDDM: its relationship to fatty acid composition

“…Reaven et al [34] showed that the extent of LDL oxidation is strongly influenced by the LDL linoleic acid content. More recently, dietary studies have shown that the enrichment of LDL linoteic acid by dietary manipulation resulted in an increase in oxidisability [35,36]; our results confirm those findings. The diabetic subjects in this study had a raised percentage of linoleic acid in their cholesteryl ester and this positively correlated with oxidisability.…”

Increased lipid peroxidation during long-term intervention with high doses of n-3 fatty acids (PUFAs) following an acute myocardial infarction

“…In the present study, the change in n-6 PUFAs in serum phospholipids differed significantly between the groups, but the intragroup increase in linoleic acid during 1 y of corn oil treatment did not reach statistical significance. Several studies support the notion that a high intake of n-6 PUFAs may increase lipid peroxidation (Reaven et al, 1991(Reaven et al, , 1993(Reaven et al, , 1994, and may explain the increase over 1 y also in our control group. Therefore, the choice of control in our study may partly mask the effect of n-3 PUFAs intervention.…”

Clinical significance of the physicochemical properties of LDL in type 2 diabetes

“…Polyunsaturated fatty acids are particularly susceptible to peroxidation by free radicals, whereas LDL particles enriched with monounsaturated fatty acids are less prone to oxidative injury [63]. In agreement with these in vitro findings, patients with type 2 diabetes treated with a diet enriched with monounsaturated fatty acids show an increased LDL lag time [64].…”