Effect of in vitro Stability of Dietary Fish Oil on Lipid Peroxidation and Prostanoids in vivo

Abstract

Dietary supplementation of rats with fish oil for 18 days resulted in signs of lipid peroxidation, with increased malondialdehyde production in plasma and myocardium. This increase in malondialdehyde could be completely prevented by supplementing the fish oil with a new natural antioxidant mixture (Pufanox^{r`</sup>) which is known to markedly increase the in vitro stability of fish oils. Addition of Pufanox<sup>r`} to fish oil also tended to increase the ratio between the vasodilator prostacyclin and the vasoconstrictor thromboxane A₂. The concentration of vitamin E decreased, both in plasma and in the heart after the period of fish oil ingestion, indicating that the fish oil used contained too little vitamin E. Plasma cholesterol and triglyceride levels decreased markedly after fish oil supplementation but with no apparent difference between fish oil with or without Pufanox^r`, probably due to the insufficient content of vitamin E. The results obtained emphasize the importance both of the in vitro stability of the fish oil given and of the amount of vitamin E added.