Review suggests optimal dose of omega-3 fatty acids for reducing blood pressure

The optimal intake for both systolic and diastolic blood pressure reduction is 2 to 3 g/d, according to a dose-response meta-analysis of 71 randomized controlled trials, although an editorial said omega-3s “are still not fully ready for prime time.”

A recent review suggested 2 to 3 g/d as the optimal dose of omega-3 polyunsaturated fatty acids to reduce blood pressure.

Researchers conducted a dose-response meta-analysis of randomized controlled trials that examined an association between omega-3 fatty acids (docosahexaenoic acid, eicosapentaenoic acid, or both) and blood pressure. They predicted the average dose-response association between daily omega-3 fatty acid intake and changes in blood pressure using a random-effects one-stage cubic spline regression model. They also looked at subgroup differences. Trials in which patients with hypertension received concurrent blood pressure-lowering medications were excluded. Results were published June 1 by the Journal of the American Heart Association.

A total of 71 trials were included, involving 4,973 individuals on a combined dose of docosahexaenoic acid plus eicosapentaenoic acid of 2.8 g/d (interquartile range, 1.3 g/d to 3.6 g/d). Overall, there was a nonlinear association between the omega-3s and blood pressure, with J-shaped dose-response curves. The optimal intakes for both systolic and diastolic blood pressure reduction were produced by moderate doses between 2 g/d (systolic blood pressure, −2.61 mm Hg [95% CI, −3.57 to −1.65 mm Hg]; diastolic blood pressure, −1.64 mm Hg [95% CI, −2.29 to −0.99 mm Hg]) and 3 g/d (systolic blood pressure, −2.61 mm Hg [95% CI, −3.52 to −1.69 mm Hg]; diastolic blood pressure, −1.80 mm Hg [95% CI, −2.38 to −1.23 mm Hg]). Subgroup analyses showed stronger and approximately linear dose-response relations among patients with hypertension, hyperlipidemia, and older age.

Limitations of the study include variations among the original trials, such as the device of blood pressure measurement (automatic vs. manual), the year of study (1987 to 2020), and the type of intervention (diet vs. supplementation), the authors noted. They added that the absence of doses between 7 g/d and 15 g/d increased the uncertainty in the effect estimates at higher doses.

The antihypertensive effects of omega-3s found by the review may overlap with that derived from existing pharmacological treatments, an accompanying editorial noted. Although pooled data suggest a net modest benefit, results from trials have been inconsistent, and there is also a risk of adverse events, the editorialists said.

Therefore, omega-3 fatty acids “are still not fully ready for prime time, and physicians should keep an open mind on these compounds” considering the mixed evidence base and the potential risks of increased atrial fibrillation and bleeding, they wrote.