Mayo Clinic Study Finds Definitive Link Between Omega-3 Intake and Cardiovascular Risk

September 18, 2020

A meta-analysis of more than 3 dozen RCTs suggests increased intake of omega-3 supplements, such as EPA and DHA, was linked to a decreased risk of myocardial infarction action and coronary heart disease events.

New research from physicians at the Mayo Clinic is providing what investigators claim is the most comprehensive analysis to date describing the impact of increased omega-3 intake on cardiovascular risk.

A meta-analysis including data from 40 clinical trials, results of the study further evidence of the effects of increased consumption of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cardiovascular health, which include reductions in myocardial infarction action and coronary heart disease events.

"The study supports the notion that EPA and DHA intake contributes to cardioprotection, and that whatever patients are getting through the diet, they likely need more," said study author Carl Lavie, MD, a cardiologist at Ochsner Health in New Orleans, in a statement from the Mayo Clinic.

“Given the safety and diminished potential for interaction with other medications, the positive results of this study strongly suggest omega-3 supplements are a relatively low-cost, high impact way to improve heart health with few associated risks and should be considered as part of a standard preventive treatment for most patients with cardiovascular diseases and those recovering from myocardial infarction,” added Lavie, later in the statement.

Few topics have garnered as much discussion as the effect of fish oil, omega-3, and related supplements on cardiovascular health. While previous research has proven low-quality versions of these are ineffective, many recent trials and reviews have given credence to the notion increased intake of EPA and DHA could prove useful for reducing cardiovascular risk.

To further explore the subject, Lavie and a team of colleagues designed the current study as a random-effects meta-analysis and meta-regression of randomized control trials with EPA/DHA supplementation. Of note, investigators pointed out the current study is an update and expansion of a meta-analysis performed by investigators from Norwich Medical School that included all RCTs meeting the aforementioned criteria published before August 2019.

Outcomes of interest in the current analysis included myocardial infarction, coronary heart disease events, coronary heart disease mortality, fatal myocardial infarction, and cardiovascular disease events, which was defined as a composite of myocardial infarction, angina, stroke, heart failure, peripheral artery disease, sudden death, and non-scheduled cardiovascular surgical interventions.

In total, 40 studies with a total of 135,267 participants were included in the meta-analysis. Results of the meta-analysis suggested supplementation was associated with a reduction in the risk of myocardial infarction (RR, 0.87; 95% CI, 0.80-0.96; high certainty number needed to treat [NNT] of 272), coronary heart disease events (RR, 0.90; 95% CI, 0.84-0.97; high certainty NNT of 192), fatal myocardial infarction (RR, 0.65; 95% CI, 0.46-0.91; moderate certainty NNT of 128), and coronary heart disease mortality (RR, 0.91; 95% CI, 0.85-0.98), low certainty NNT of 431). However, investigators noted supplementation was noted associated with a reduction in the composite cardiovascular disease event endpoint (RR, 0.95; 95% CI, 0.90-1.00). Additionally, investigators noted the associations observed in the study was dose-dependent for cardiovascular events and myocardial infarction.

In the statement from the Mayo Clinic, investigators note the results of this study further validate the results of a meta-analysis by physicians from the Harvard School of Public Health that examined the topic in the 13 largest clinical studies.

“When separate analyses arrive at similar results, that's not only validating; it also underscores the science base needed to inform future intake recommendations," said co-author Aldo Bernasconi, PhD, Vice President of Data Science for the Global Organization for EPA and DHA Omega-3s (GOED), Salt Lake City, UT, USA, which commissioned this study. "Because this paper included more studies and all dosages, the estimates for a dose-response are more precise and the conclusions stronger."

This study, “Effect of Omega-3 Dosage on Cardiovascular Outcomes: An Updated Meta-Analysis and Meta-Regression of Interventional Trials,” was published in Mayo Clinic Proceedings.