Forever21, on 8-Jul 2008, 05:30 AM, said:
Sorry, layman here. Does that mean Fish Oils are pro-oxidants and defeating the whole purpose of taking anti-oxidant diet/supplements?
I'm taking OmegaRX EPA/DHA by The Zone (4,000 mg x 4 times daily)
, fish oil is less oxidative than you'd think. (But your dose does seem huge. Are you treating some inflammatory condition?)
Pharmacol Res. 2008 May 18. [Epub ahead of print]
Polyunsaturated fatty acids as antioxidants.
Richard D, Kefi K, Barbe U, Bausero P, Visioli F.
Laboratory of «Micronutrients and Cardiovascular Disease», UMR7079, UPMC Univ 06, Paris, France.
The susceptibility of fatty acids to oxidation is thought to be directly dependent on their degree of unsaturation. However, some in vitro and in vivo studies suggest that the relation between chemical structure and susceptibility to oxidation is not as straightforward as hypothesized from theoretical viewpoints. Indeed, long chain polyunsaturated fatty acids (LC-PUFAs) might be less oxidizable than others under specific experimental conditions. We investigated the free radical-scavenging potential of PUFA and the production of reactive oxygen/nitrogen (ROS/RNS) species by human aortic endothelial cells (HAECs) supplemented with different fatty acids. Fatty acid micelles scavenged superoxide in an unsaturation-dependent manner, up to eicosapentaenoic acid, which was the most effective fatty acid. Supplementation of HAEC with polyunsaturated fatty acids of the omega 3 series resulted in lower formation of ROS, as compared with cells supplemented with saturates, monounsaturates, or polyunsaturates of the omega 6 series.
This effect was maximal at concentrations of 10muM. The effects of omega 3 fatty acids on reactive species production appear to be stronger when ROS were evaluated, as a milder, albeit significant effect was observed on RNS generation. Based on in vivo data showing reduced excretion of lipid peroxidation products after omega 3 intake and our data on ROS production and direct superoxide scavenging by LC-PUFAs, notably those of the omega 3 series, we propose that this series of fatty acid might act as indirect anti- rather than pro-oxidant in vascular endothelial cells, hence diminishing inflammation and, in turn, the risk of atherosclerosis and cardiovascular disease.
J Lipid Res. 2001 Mar;42(3):407-18.
Supplementation of postmenopausal women with fish oil does not increase overall oxidation of LDL ex vivo compared to dietary oils rich in oleate and linoleate.
Higdon JV, Du SH, Lee YS, Wu T, Wander RC.
Department of Nutrition and Food Management, Oregon State University, Corvallis, OR 97331, USA.
Although replacement of dietary saturated fat with monounsaturated and polyunsaturated fatty acids (MUFA and PUFA) has been advocated for the reduction of cardiovascular disease risk, diets high in PUFA could increase low density lipoprotein (LDL) susceptibility to oxidation, potentially contributing to the pathology of atherosclerosis. To investigate this possibility, 15 postmenopausal women in a blinded crossover trial consumed 15 g of sunflower oil (SU) providing 12.3 g/day of oleate, safflower oil (SA) providing 10.5 g/day of linoleate, and fish oil (FO) providing 2.0 g/day of eicosapentaenoate (EPA) and 1.4 g/day of docosahexaenoate (DHA). During CuSO(4)-mediated oxidation, LDL was depleted of alpha-tocopherol more rapidly after FO supplementation than after supplementation with SU (P = 0.0001) and SA (P = 0.05). In LDL phospholipid and cholesteryl ester fractions, loss of n-3 PUFA was greater and loss of n-6 PUFA less after FO supplementation than after SU and SA supplementation (P < 0.05 for all), but loss of total PUFA did not differ. The lag phase for phosphatidylcholine hydroperoxide (PCOOH) formation was shorter after FO supplementation than after supplementation with SU (P = 0.0001) and SA (P = 0.006), whereas the lag phase for cholesteryl linoleate hydroperoxide (CE18:2OOH) formation was shorter after FO supplementation than after SU (P = 0.03) but not SA. In contrast, maximal rates of PCOOH and CE18:2OOH formation were lower after FO supplementation than after SA (P = 0.02 and 0.0001, respectively) and maximal concentrations of PCOOH and CE18:2OOH were lower after FO supplementation than after SA (P = 0.03 and 0.0006, respectively). Taken together, our results suggest that FO supplementation does not increase the overall oxidation of LDL ex vivo, especially when compared with SA supplementation. Consequently, health benefits related to increased fish consumption may not be offset by increased LDL oxidative susceptibility.
Am J Clin Nutr. 2000 Sep;72(3):714-22.
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 F(2)-isoprostanes.
Higdon JV, Liu J, Du SH, Morrow JD, Ames BN, Wander RC.
Department of Nutrition and Food Management, Oregon State University, Corvallis, USA.
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. DESIGN: Fifteen postmenopausal women took 15 g sunflower oil/d, providing 12.3 g oleate/d; safflower oil, providing 10.5 g linoleate/d; and fish oil, providing 2.0 g EPA/d and 1.4 g DHA/d in a 3-treatment crossover trial. 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 fish-oil 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.
Redox Rep. 2004;9(4):193-7.
Effect of fish and fish oil-derived omega-3 fatty acids on lipid oxidation.
School of Medicine and Pharmacology, The University of Western Australia, Medical Research Foundation Building, Box X 2213 GPO, Perth, Western Australia 6847, Australia. firstname.lastname@example.org
There is evidence that omega-3 (omega3) fatty acids derived from fish and fish oils reduce the risk of cardiovascular disease via mechanisms underlying atherosclerosis, thrombosis and inflammation. Despite these benefits, there has been concern that these fatty acids may increase lipid peroxidation. However, the in vivo data to date are inconclusive, due in part to limitations in the methodologies. In this regard, our findings using the measurement of F(2)-isoprostanes, a reliable measure of in vivo lipid peroxidation and oxidant stress, do not support adverse effects of omega3 fatty acids on lipid peroxidation.