Long-chain omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid and blood pressure: a meta-analysis of randomized controlled trials

Background: Although a large body of literature has been devoted to examining the relationship between eicosapentaenoic and docosahexaenoic acids (EPA+DHA) and blood pressure, past systematic reviews have been hampered by narrow inclusion criteria and a limited scope of analytical subgroups. In addition, no meta-analysis to date has captured the substantial volume of randomized controlled trials (RCTs) published in the past 2 years. The objective of this meta-analysis was to examine the effect of EPA+DHA, without upper dose limits and including food sources, on blood pressure in RCTs.

Methods: Random-effects meta-analyses were used to generate weighted group mean differences and 95% confidence intervals (CIs) between the EPA+DHA group and the placebo group. Analyses were conducted for subgroups defined by key subject or study characteristics.

Results: Seventy RCTs were included. Compared with placebo, EPA+DHA provision reduced systolic blood pressure (-1.52 mm Hg; 95% confidence interval (CI) = -2.25 to -0.79) and diastolic blood pressure (-0.99 mm Hg; 95% CI = -1.54 to -0.44) in the meta-analyses of all studies combined. The strongest effects of EPA+DHA were observed among untreated hypertensive subjects (systolic blood pressure = -4.51 mm Hg, 95% CI = -6.12 to -2.83; diastolic blood pressure = -3.05 mm Hg, 95% CI = -4.35 to - 1.74), although blood pressure also was lowered among normotensive subjects (systolic blood pressure = -1.25 mm Hg, 95% CI = -2.05 to -0.46; diastolic blood pressure = -0.62 mm Hg, 95% CI = -1.22 to -0.02).

Conclusions: Overall, available evidence from RCTs indicates that provision of EPA+DHA reduces systolic blood pressure, while provision of ≥2 grams reduces diastolic blood pressure.