Study objective: To evaluate the effects of omega-3 fatty acids on blood pressure control and lipid levels.
Design: Double-blind, placebo-controlled, randomized study.
Setting: Veterans Affairs Medical Center teaching hospital.
Patients: Twenty-one men whose blood pressure was not optimally controlled with antihypertensive agents, who met the inclusion criteria.
Interventions: Patients were randomized to receive either fish oil (4.5 g omega-3 fatty acids/day) or placebo.
Measurements and main results: Blood pressure readings were taken at baseline, and 4 and 8 weeks. Sitting systolic and diastolic blood pressures were significantly reduced in the fish oil group at both week 4 (148/97 to 132/90, p <0.05) and week 8 (148/97 to 134/91, p <0.05). Sitting diastolic blood pressure was significantly reduced in the placebo group at week 8 (94 to 88, p <0.05). There was no difference in percentage change of sitting systolic and diastolic pressures at week 8 comparing the placebo group (-6.4% and -6.3%, respectively) and the fish oil group (-8.8% and -6.6%, respectively). Triglyceride levels (-40.9%, p <0.05) and platelet counts (-8.7%, p <0.05) were significantly reduced at 4 weeks, and low-density lipoprotein (LDL) cholesterol levels were significantly increased both at 4 and 8 weeks (13.5% and 19.1%, respectively) in the fish oil group.
Conclusion: Adjunctive fish oil supplementation did not substantially augment blood pressure lowering in treated hypertensive men with suboptimally controlled blood pressure. Effects on plasma lipid values were mixed, with an increase in LDL cholesterol and a decrease in plasma triglyceride levels.