Supplementation of postmenopausal women with fish oil rich in eicosapentaenoic acid and docosahexaenoic acid is not associated with greater in vivo lipid peroxidation compared with oils rich in oleate and linoleate as assessed by plasma malondialdehyde and F2-isoprostanes

Abstract

Background: Although the replacement of dietary saturated fat with unsaturated fat has been advocated to reduce the risk of cardiovascular disease, diets high in polyunsaturated fatty acids (PUFAs) could increase lipid peroxidation, potentially contributing to the pathology of atherosclerosis. Objective: The objective of this study was to examine indexes of in vivo lipid peroxidation, including free F 2 -isoprostanes, malondialdehyde (MDA), and thiobarbituric acid reacting substances (TBARS), in the plasma of postmenopausal women taking dietary oil supplements rich in oleate, linoleate, and both eicosapentaenoic acid and docosahexaenoic acid. Results: Plasma free F 2 -isoprostane concentrations were lower after fish-oil supplementation than after sunflower-oil supplementation (P = 0.003). When plasma free F 2 -isoprostane concentrations were normalized to plasma arachidonic acid concentrations, significant differences among the supplements were eliminated. Plasma MDA concentrations were lower after fishoil supplementation than after sunflower-oil supplementation (P = 0.04), whereas plasma TBARS were higher after fish-oil supplementation than after sunflower oil (P = 0.003) and safflower oil (P = 0.001) supplementation. When plasma MDA concentrations were normalized to plasma PUFA concentrations, significant differences were eliminated, but TBARS remained higher after fish-oil supplementation than after sunflower oil (P = 0.01) and safflower-oil (P = 0.0003) supplementation. Conclusions: With fish-oil supplementation, there was no evidence of increased lipid peroxidation when assessed by plasma F 2 -isoprostanes and MDA, although plasma TBARS was higher than with sunflower-oil and safflower-oil supplementation. Am J Clin Nutr 2000;72:714-22.

Oxidant and antioxidant status in vegetarians and fish eaters

“…This finding is in agreement with the study of Higdon et al (16) who studied in vivo oxidation by measuring plasma MDA and F2 isoprostanes (a more specific indicator of lipid peroxidation). Similar studies by Calvilleo et al (17) have shown that susceptibility of rat erythrocytes to oxidative stress is not affected by supplementation of n-3 fatty acids.…”

A diet containing rapeseed oil-based fats does not increase lipid peroxidation in humans when compared to a diet rich in saturated fatty acids

“…However, another study with n-3 fatty acid supplementation indicated that the in vivo lipid peroxidation was not increased (Higdon et al, 2000). Differences in the antioxidant content of the diets together with differences in the degree of unsaturation and oxidisability of fatty acids in the diets may partly explain the discrepancy between lipid peroxidation outcomes in these studies.…”

Effects of docosahexaenoic acid supplementation on blood lipids, estrogen metabolism, and in vivo oxidative stress in postmenopausal vegetarian women

“…Two research groups found a decrease in F 2 -isoprostane with higher doses of n-3 fatty acids than ours. One of these studies involved postmenopausal women supplemented with fish oil at a dose of 3.4 g n-3 fatty acids per day but significant differences of plasma F 2 -isoprostane were eliminated when the values were normalized to plasma AA concentrations (Higdon et al, 2000). Subjects in the other study were hypertensive type II diabetic patients (Mori et al, 2003).…”

“…Nevertheless, the influence of fish oil supplementation on some indicators of oxidative stress was not consistent (Meydani et al, 1991;Higdon et al, 2000), partly because n-3 fatty acids also enhanced the activities and expression of antioxidant enzymes, such as catalase, glutathione peroxidase and superoxide dismutase (Takahashi et al, 2002;Wang et al, 2004). Therefore, to examine whether DHA supplementation actually induces oxidative stress in vivo in vegetarians, levels of urinary F 2 -isoprostanes and plasma a-tocopherol were measured.…”