The effects of fish oil on triglycerides, cholesterol, fibrinogen and malondialdehyde in humans supplemented with vitamin E.

The effects of fish oils supplemented with 0.3 IU/g and 1.5 IU/g of vitamin E were compared in a double-blind, cross-over study. Twelve healthy volunteers were given 30 mL/day of either oil for 3 wk. Intake of the vitamin E-rich fish oil resulted in a marked decrease in serum triglycerides (48%) and in fibrinogen (11%). After administration of the low vitamin E-containing oil there was a considerably smaller reduction of serum triglycerides and no significant reduction of fibrinogen. Both oils caused an increase in high density lipoprotein cholesterol and a decrease in the atherogenic index, but neither oil altered the total cholesterol level. Serum vitamin E was decreased by 9% and plasma malondialdehyde was increased by 122% after intake of the low vitamin E-containing oil, but both remained normal after intake of the other oil. The effect of vitamin E may be due to inhibition of fatty acid peroxidation with less formation of malondialdehyde and a larger amount of active (n-3) fatty acids in their sites of action in the liver, resulting in a greater decrease in the synthesis of triglycerides and fibrinogen.