Higher omega-3 fatty acid intake may be necessary to reduce blood pressure.

Nearly two-thirds of adults living in the United States have high blood pressure, defined as having a systolic pressure of 130 mmHg or higher or a diastolic pressure of 80 mmHg or higher. High blood pressure increases a person’s risk for heart disease and stroke and contributes to small vessel disease, a major risk factor for cardiovascular disease, dementia, and stroke. Although some evidence suggests that omega-3s reduce blood pressure, researchers have not identified the optimal dose necessary to achieve this effect. Findings of a recent meta-analysis suggests that 3 grams of omega-3 fatty acids daily reduce blood pressure.

Observational data suggest that omega-3 fatty acids, especially fish-derived eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are cardioprotective. For example, a prospective study involving more than 20,000 healthy males found that those who ate one to two servings of fish twice a week had a lower risk of sudden cardiac death than those who ate fish less than once a month, likely due to the omega-3s found in fish. But the findings from the five decades of study have been remarkably inconsistent, with some studies showing benefits, and others not. Some of these inconsistencies have arisen from differences in study designs, which vary markedly in terms of study population, dose, and duration.

The authors of the analysis searched the scientific literature for randomized controlled trials investigating associations between omega-3 fatty acids and blood pressure. Then they filtered their findings based on a set of criteria designed to identify high-quality studies. Finally, they combined data from these high-quality studies and reanalyzed them so they could interpret the results on a large scale.

They identified 71 trials, involving nearly 5,000 participants. On average, those who consumed 2 to 3 grams of combined EPA and DHA daily experienced reductions in blood pressure of approximately 2 mm Hg (and as much as 3.5 mm Hg). Participants who had high blood pressure and consumed more than 3 grams of EPA and DHA daily experienced reductions of 4.5 mm Hg for those with hypertension, compared to about 2 mm Hg for those without. Higher doses (5 grams daily) of omega-3s did not confer any additional benefit, with blood pressure decreasing by approximately 4 mm Hg for those with hypertension and less than 1 mm Hg for those without.

These findings suggest that 3 grams of combined EPA and DHA daily is the optimal dose of omega-3 fatty acids necessary to achieve reductions in blood pressure. Learn more about the heart-health benefits of omega-3s in this episode featuring Dr. Bill Harris.

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