Platelet function, thromboxane formation and blood pressure control during supplementation of the western diet with cod liver oil

Abstract

Epidemiologic and experimental data suggest an antiatherothrombotic potential of ω-3 polyunsaturated fatty acids. Therefore, the Western diet, which supplies predominantly ω-6 polyunsaturated fatty acids, was supplemented with 40 ml/day of cod liver oil, which provides about 10 g of ω-3 polyunsaturated fatty acids daily, for 25 days in eight volunteers. The ω-3 polyunsaturated fatty acids were incorporated in platelet and erythrocyte membrane phospholipids at the expense of ω-6 polyunsaturated fatty acids. Bleeding time increased (p<0.01) and platelet count (p<0.05), platelet aggregation upon ADP and collagen (p<0.01-0.05), and associated thromboxane B2 formation (p<0.01) decreased. Blood pressure (p<0.05) and blood pressure response to norepinephrine (p<0.01) and angiotensin II (NS) fell, without major changes in plasma catecholamines, renin, urinary aldosterone, kallikrein, prostaglandins E2 and F(2α) and red cell cation fluxes. Biochemical and functional changes were reversed 4 weeks after cod liver oil was discontinued. Formation of prostaglandins derived from eicosapentaenoic acid and interference of eicosapentaenoic acid with formation and action of prostaglandins derived from arachidonic acid were evident in vitro. Whatever the mechanism, this moderate supplement of ω-3 polyunsaturated fatty acids markedly changed membrane phospholipids, which was associated with a shift toward less reactive platelets and a blunted circulatory response to pressure hormones.