Also see:
Fish Oil Toxicity
PUFA, Fish Oil, and Alzheimers
The Randle Cycle
Women, Estrogen, and Circulating DHA
PUFA – Accumulation & Aging
Medium Chain Fats, Ketones, and Brain Function
PUFA, Development, and Allergy Incidence
Dietary PUFA Reflected in Human Subcutaneous Fat Tissue
Commentary on Type 2 Diabetes
The Great Fish Oil Experiment – Ray Peat
Instead of helping, fish oil drives people towards a heart attack
Too Much of a Good(?) Thing: When Fish Oil Starts Clogging Your Arteries and Fattening Up Your Liver.
Lipids. 1997 May;32(5):535-41.
Lipid peroxidation during n-3 fatty acid and vitamin E supplementation in humans.
Allard JP, Kurian R, Aghdassi E, Muggli R, Royall D.
The purpose of this study was to investigate in healthy humans the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake, alone or in combination with dL-alpha-tocopherol acetate (vitamin E) supplements on lipid peroxidation. Eighty men were randomly assigned in a double-blind fashion to take daily for 6 wk either menhaden oil (6.26 g, n-3 fatty acids) or olive oil supplements with either vitamin E (900 IU) or its placebo. Antioxidant vitamins, phospholipid composition, malondialdehyde (MDA), and lipid peroxides were measured in the plasma at baseline and week 6. At the same time, breath alkane output was measured. Plasma alpha-tocopherol concentration increased in those receiving vitamin E (P < 0.0001). In those supplemented with n-3 fatty acids, EPA and DHA increased in plasma phospholipids (P < 0.0001) and plasma MDA and lipid peroxides increased (P < 0.001 and P < 0.05, respectively). Breath alkane output did not change significantly and vitamin E intake did not prevent the increase in lipid peroxidation during menhaden oil supplementation. The results demonstrate that supplementing the diet with n-3 fatty acids resulted in an increase in lipid peroxidation, as measured by plasma MDA release and lipid peroxide products, which was not suppressed by vitamin E supplementation.
J Nutr. 1991 Apr;121(4):484-91.
Effect of long-term fish oil supplementation on vitamin E status and lipid peroxidation in women.
Meydani M, Natiello F, Goldin B, Free N, Woods M, Schaefer E, Blumberg JB, Gorbach SL.
Fifteen young (22-35 y) and 10 older (51-71 y) women received six capsules of fish oil (Pro-Mega)/d, providing a total of 1,680 mg eicosapentaenoic (EPA), 720 mg docosahexaenoic (DHA), 600 mg other fatty acids, and 6 IU vitamin E. Blood was collected before and after 1, 2 and 3 mo of supplementation. Compliance was confirmed by the significant increase in plasma EPA and DHA in all women. Older women had a significantly higher increase in EPA and DHA than did young women (10-fold increases in EPA and 2.5-fold increases in DHA vs. 8-fold in EPA and 2-fold in DHA for older and young women, respectively). The decrease in the arachidonic acid:EPA ratio was more dramatic in the older women. Plasma total triglycerides (TG) decreased significantly, and the ratio of polyunsaturated fatty acids to saturated fatty acids was significantly (P less than 0.01) increased. Plasma vitamin E levels did not change significantly after supplementation; however, after 3 mo of supplementation by young women, plasma vitamin E was significantly lower than after 1 mo. The vitamin E: TG ratio was significantly increased and vitamin E:(EPA + DHA) significantly decreased. All women showed a significant increase in plasma lipid peroxide through mo 2 of supplementation. After 2 mo, older women had significantly higher lipid peroxide levels than young women. The lipid peroxide:TG ratio, which declined by mo 3, was still significantly higher than baseline. These data indicate that although long-term fish oil supplementation may be beneficial in reducing plasma total TG, susceptibility of plasma lipids to free radical attack is potentiated.(ABSTRACT TRUNCATED AT 250 WORDS)
J Nutr. 1992 Nov;122(11):2190-5.
Lipid peroxidation products are elevated in fish oil diets even in the presence of added antioxidants.
Gonzalez MJ, Gray JI, Schemmel RA, Dugan L Jr, Welsch CW.
Purified corn and fish oil diets with different types and concentrations of antioxidants were evaluated for oxidation products. In addition, a determination of different organ and carcass oxidation product levels was performed. Peroxide value and thiobarbituric acid assays were performed on the diets immediately after mixing (0 h) and 24, 48 and 72 h after being fed to mice. The AIN-recommended level of antioxidant addition (butylated hydroxytoluene, 0.02 g/100 g oil) and even the addition of 100 times this level (2 g/100 g oil), although decreasing the level of oxidation products, failed to totally prevent oxidative deterioration in diets high in fish oil. Furthermore, other antioxidants added in excess to the fish oil diets also failed to completely suppress oxidative deterioration of the diets and, in addition, when fed daily to mice for a period of 4 wk, caused an accumulation of lipid peroxidation products in certain organs (e.g., heart, skeletal muscle, mammary glands) and in the carcass. These results provide evidence that in the preparation of fish oil diets, the addition of antioxidants at the AIN-recommended level, or even levels substantially higher, does not completely suppress oxidative deterioration of experimental diets.
