Omega-3 polyunsaturated fatty acid supplements and ambulatory blood pressure monitoring parameters in patients with mild essential hypertension

OBJECTIVE: To evaluate the effects of low doses of omega-3 polyunsaturated fatty acids on ambulatory blood pressure monitoring parameters in a group of mild essential hypertensives. PATIENTS: We studied 24 consecutive essential hypertensive patients from our outpatient clinic with mild hypertension (diastolic blood pressure < or = 105 mmHg), no previous treatment for 4 weeks at least and no other disease. METHODS: After a 3-month run-in period, the patients entered an intervention phase and were given 3 g omega-3 polyunsaturated fatty acids (85% eicosapentaenoic and docosahexaenoic acid concentrate) daily for 4 months; this phase was followed by a 4-month washout period. Ambulatory blood pressure monitoring was performed at the end of each phase; erythrocyte membrane fatty acids were assessed to check compliance. RESULTS: After 4 months of treatment, erythrocyte omega-3 polyunsaturated fatty acids significantly increased but average systolic and diastolic blood pressure and the heart rate did not significantly change; no significant variations were recorded in blood pressure or heart rate variability (assessed as blood pressure and heart rate SD) nor in the diurnal blood pressure rhythm. After washout, a significant decrease was observed in erythrocyte omega-3 polyunsaturated fatty acids but the ambulatory blood pressure monitoring parameters were not substantially modified. CONCLUSIONS: The present data show that low doses of omega-3 polyunsaturated fatty acids as a single treatment are not effective in lowering blood pressure or the heart rate in mild essential hypertensive patients, despite a significant change in fatty acid cell membrane composition. Nor does this treatment seem likely to affect blood pressure variability or the diurnal rhythm.