Article: PDF OnlyThe effect of fish oil on blood pressure and high-density lipoprotein-cholesterol levels in phase I of the Trials of Hypertension PreventionSacks, Frank M.1; Hebert, Patricia1; Appel, Lawrence J.2; Borhani, Nemat O.3; Applegate, William B.4; Cohen, Jerome D.5; Cutler, Jeffrey A.6; Kirchner, Kent A.7; Kuller, Lewis H.8; Roth, Katherine J.5; Taylor, James O.1,9; Hennekens, Charles H. for the Trials of Hypertension Prevention Collaborative Research GroupAuthor Information From the 1Channing Laboratory and Preventive Medicine Divisions, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School; 2Johns Hopkins University School of Medicine and of Hygiene and Public Health, Baltimore, Maryland; 3University of California, Davis, California; 4University of Tennessee, Memphis, Tennessee; 5St Louis University, St Louis, Missouri; the 6National Heart, Lung, and Blood Institute, Bethesda, Maryland; 7University of Mississippi, Jackson, Mississippi; 8University of Pittsburgh School of Public Health, Pittsburgh, Pennsylvania; and 9East Boston Neighborhood Health Center, East Boston, Massachusetts, USA. Journal of Hypertension: Volume 12 - Issue - p S33-S38 Buy Abstract Objective To study the effects of moderate doses of fish oil on blood pressure and high-density lipoprotein (HDL)-cholesterol. Methods The participants were 350 normotensive men and women aged 30–54 years who were enrolled from seven academic medical centers in phase I of the Trials of Hypertension Prevention. They were randomly assigned to receive placebo or 6g purified fish oil once a day, which supplied 3g n-3 polyunsaturated fatty acids for 6 months. Results Baseline blood pressure was (mean ± SD) 123±9/81 ±5mmHg. The mean differences in the blood pressure changes between the fish oil and placebo groups were not statistically significant. There was no tendency for fish oil to reduce blood pressure more in subjects with baseline blood pressures in the upper versus the lower quartile (132/87 versus 114/75 mmHg), low habitual fish consumption (0.4 versus 2.9 times a week) or low baseline plasma levels of n-3 fatty acids. Fish oil increased HDL2-cholesterol significantly compared with the placebo group. Subgroup analysis showed this effect to be significant in the women but not in the men. Increases in serum phospholipid n-3 fatty acids were significantly correlated with increases in HDL2-cholesterol and decreases in systolic blood pressure. Conclusion Moderate amounts of fish oil (6g/day) are unlikely to lower blood pressure in normotensive persons, but may increase HDL2-cholesterol, particularly in women. © Lippincott-Raven Publishers.