A meta-analysis describing the dosing relationship between omega-3 fatty acid supplementation and blood pressure was recently published in the Journal of the American Heart Association. A systematic literature search yielded 71 eligible randomized controlled trials included in the analysis, with an overall sample size of nearly 5,000 participants aged 22 to 86. Seventy-nine percent of these trials were done in participants without hypertension or hyperlipidemia, with an average duration of 10 weeks. Most studies were conducted using fish or algae oil, though a small number used a dietary fish intervention. Additionally, roughly 75% of the studies used EPA and DHA at an average combined dose of 2.8 g per day.

This meta-analysis found a non-linear dose-response relationship between omega-3s and both systolic and diastolic blood pressure. In the overall analysis, a J-shaped curve was found, and a dose of 2-3 g EPA/DHA per day was associated with the greatest reduction in blood pressure. However, a subgroup analysis of only participants with a systolic blood pressure greater than 130mmHg found an approximately linear trend between blood pressure and dosage, with similar findings for those with hyperlipidemia. Overall this suggests that exceeding 2-3 g per day may have no additional benefit in patients without hypertension or hyperlipidemia, but in patients with either of those conditions, a higher dose may be associated with greater benefit.