The influence of a fish oil high in docosahexaenoic acid on plasma lipoprotein and vitamin E concentrations and haemostatic function in healthy male volunteers.

Nine healthy male subjects consumed a daily fish oil supplement providing 2.1 g docosahexaenoic acid (22:6 n-3; DHA) and 0.8 g eicosapentaenoic acid (20:5 n-3; EPA) for 6 weeks. The proportion of EPA and DHA in plasma, erythrocytes, leucocytes and platelet phospholipids was increased by the supplement. Plasma concentration of triacylglycerol and very-low-density-lipoprotein-cholesterol were lowered and those of high-density-lipoprotein (HDL)- and HDL2-cholesterol and apoprotein B were increased. Platelet aggregation and thromboxane B2 production induced by collagen were partially inhibited. Both systolic and diastolic blood pressure fell during treatment and rose following withdrawal of the supplement. Statistically significant reductions in erythrocyte counts, packed cell volume and haemoglobin and increases in total leucocyte and monocyte counts occurred with the supplement. Plasma alpha-tocopherol concentrations fell below the normal range during the period of supplementation. It is suggested that future studies consider components other than EPA in fish oil. Further studies are needed to investigate the extent to which fish oil increases the requirement for antioxidant nutrients.