An omega-3 fatty acid daily intake of approximately 3 grams, either in the form of supplements or food, may reduce blood pressure, a new meta-analysis suggests.
The findings showed a substantial reduction in diastolic and systolic blood pressure when individuals consumed a moderate amount of omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) combined, in doses of 2 to 3 grams per day.
This association for systolic blood pressure was slightly more marked in study groups with a mean age of 45 years or older, reported Xin Zhang, PhD, of Macau University of Science and Technology in Taipa, China, and colleagues.
The results were published online June 1 in the Journal of the American Heart Association.
This report expands the prior literature by including more recent studies and uses a novel statistical method, the study authors note.
“An optimal dose of omega-3 fatty acids is potentially needed for blood pressure control in the general population, but individuals who are at high risk of developing cardiovascular diseases may benefit from higher doses,” the researchers conclude.
Prior research on omega-3 fatty acids over the last 25 years has shown conflicting results, noted Srihari S. Naidu, MD, professor of medicine at New York Medical College in Valhalla, who was not involved in the study.
“The most recent large trials, two of them — one being STRENGTH and the other being REDUCE-IT — showed conflicting results, and more importantly, they also showed that there may be an increased risk of bleeding and other complications such as atrial fibrillation,” Naidu said.
“Most cardiovascular professionals such as myself are a little bit averse to using these medications especially because we do have an aging population that has atrial fibrillation and bleeding tendency, especially if they have had stents or other cardiovascular procedures,” he told theheart.org | Medscape Cardiology during a phone interview.
The meta-analysis was based on 71 randomized controlled trials that included 4973 participants. The trials were selected if they were published prior to May 7, 2021; analyzed the link between blood pressure and various omega-3 fatty acids, such as DHA, EPA, or both; and had study participants who were 18 years of age or older.
The analysis used a new “leave one out” research technique. For the sensitivity analysis, investigators adopted an approach whereby they performed numerous dose-response assessments to determine the influence of the missing research on the total average blood pressure change.
“A nonlinear association was found overall or in most subgroups depicted as J-shaped dose-response curves,” the authors report.
The optimal intakes of omega-3 fatty acids associated with reductions in both systolic and diastolic blood pressure were seen with “moderate doses,” they note, between 2 grams per day, associated with systolic blood pressure reductions of 2.61 mm Hg and 1.64 mm Hg diastolic, and 3 grams per day, with a systolic blood pressure reduction of 2.61 mm Hg and a diastolic blood pressure reduction of 1.69 mm Hg.
However, exceeding the recommended 3 grams per day of omega-3 fatty acid consumption was not associated with other benefits, especially in normotensive patients, they note.
Notably, the subgroup analysis showed elderly people, those with hypertension, and those with hyperlipidemia had greater responses with higher doses.
“Not Entirely Novel,“ but “Robust”
In an accompanying editorial, Marc George, MRCP, PhD, Queen Mary University of London, Royal London Hospital Barts Health NHS Trust, and Ajay Gupta, MD, PhD, William Harvey Research Institute, Barts & The London School of Medicine and Dentistry, UK, point out that “although these findings are not entirely novel, they are robust and provide insights into the long‐standing debate on the role of omega-3 polyunsaturated fatty acids (PUFAs) in modifying cardiovascular risk.”
Despite uncertainty around discordant randomized trial results, they note, “pooled data suggest a net modest beneficial effect of omega-3 PUFAs, particularly on cardiovascular mortality in patients at high risk and with raised triglycerides.”
Results of the analysis show intake of omega-3 fatty acids is associated with a blood pressure lowering effect, “and a dose of 2 to 3 grams appears to be optimal,” they write. “Given the modest effect on triglycerides, this blood pressure‐lowering impact together with their other pleiotropic effects are likely the missing link to explain the cardiovascular risk reduction seen in REDUCE‐IT and subsequent meta‐analyses.”
However, further randomized trials and postmarketing studies are required to “resolve the remaining questions, particularly one that was raised by the disparity between REDUCE‐IT and STRENGTH of EPA monotherapy versus the combination of EPA and DHA,” they conclude.
“Therefore, omega-3 PUFAs are still not fully ready for primetime, and physicians should keep an open mind on these compounds with acute awareness toward of the mixed evidence base and the potential risks of increased atrial fibrillation and bleeding when prescribing,” they add.
Zhang, Naidu, George, and Gupta have reported no relevant financial relationships. The study was supported by the Macau Science and Technology Development Fund and faculty research grants from the Macau University of Science and Technology.
J Am Heart Assoc. Published online June 1, 2022. Full text, Editorial
Ashley Lyles is an award-winning medical journalist. She is a graduate of New York University’s Science, Health, and Environmental Reporting Program. Previously, she studied professional writing at Michigan State University, where she also took premedical classes. Her work has appeared in outlets like The New York Times Daily 360, PBS NewsHour, The Huffington Post, Undark, The Root, Psychology Today, Insider, and Tonic (Health by Vice), among other publications.
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