Long-chain omega-3 fatty acids and blood pressure.

Background: High dose fish oil supplementation reduces blood pressure (BP) in hypertensive patients. The current study examines how modest variations in omega-3 fatty acid intake may affect BP in a healthy community sample.

Methods: Study participants included 265 Pittsburgh-area adults 30-54 years of age (11% black, 51% female) not taking omega-3 fatty acid supplements or antihypertensive medications. Standardized assessments of clinic and 24-h ambulatory BP, and pulse rate were obtained. Docosahexanenoic acid (DHA) and eicosapentaenoic acid (EPA) in fasting serum phospholipids were measured by capillary gas chromatography. Regression analyses controlled for age, gender, race, body mass index (BMI), self-reported sodium intake, and physical activity.

Results: Participants included 181(68%) normotensives, 66 (25%) prehypertensives, and 18 (7%) persons with untreated hypertension. DHA was inversely associated with clinic diastolic (β = -0.121, P = 0.03), awake ambulatory diastolic BP (β = -0.164, P = 0.004), and 24-h diastolic BP (β = -0.135, P = 0.02). A two standard deviation greater DHA was associated with 2.1 mm Hg lower clinic and 2.3 mm Hg lower awake ambulatory diastolic BP. In addition, DHA was inversely associated with pulse rate measured at rest in the clinic. EPA was related to clinic pulse rate but not clinic or ambulatory BP.

Conclusion: In this sample of American adults not on antihypertensive medications, a modest, inverse association was found between DHA exposure and both clinic and ambulatory diastolic BP. Therefore, increasing DHA consumption through diet modification rather than large dose supplementation represents a candidate strategy for future studies of hypertension prevention.