EFFECT OF EICOSAPENTAENOIC AND DOCOSAHEXAENOIC ACIDS ON BLOOD-PRESSURE IN HYPERTENSION - A POPULATION-BASED INTERVENTION TRIAL FROM THE TROMSO STUDY

Studies of whether polyunsaturated fatty acids in fish oil — in particular, eicosapentaenoic and docosahexaenoic acids — lower blood pressure have varied in design and results. We conducted a population-based, randomized, 10-week dietary-supplementation trial in which the effects of 6 g per day of 85 percent eicosapentaenoic and docosahexaenoic acids were compared with those of 6 g per day of corn oil in 156 men and women with previously untreated stable, mild essential hypertension. The mean systolic blood pressure fell by 4.6 mm Hg (P = 0.002), and diastolic pressure by 3.0 mm Hg (P = 0.0002) in the group receiving fish oil; there was no significant change in the group receiving corn oil. The differences between the groups remained significant for both systolic (6.4 mm Hg; P = 0.0025) and diastolic (2.8 mm Hg; P = 0.029) pressure after control for anthropometric, lifestyle, and dietary variables. The decreases in blood pressure were larger as concentrations of plasma phospholipid n—3 fatty acids increased (P = 0.027). Dietary supplementation with fish oil did not change mean blood pressure in the subjects who ate fish three or more times a week as part of their usual diet, or in those who had a base-line concentration of plasma phospholipid n—3 fatty acids above 175.1 mg per liter. We conclude that eicosapentaenoic and docosahexaenoic acids reduce blood pressure in essential hypertension, depending on increases in plasma phospholipid n—3 fatty acids. (N Engl J Med 1990; 322:795–801.). © 1990, Massachusetts Medical Society. All rights reserved.