Consuming omega-3 fatty acids could reduce cardiac death by an average of 8 percent, according to a comprehensive new study published in the Journal of Clinical Lipidology.
The study looked 14 randomized, controlled trials (RCTs) of 71,899 people, and found that consumption of EPA and DHA omega-3s reduced the risk of cardiac death. Cardiac death accounts for about two-thirds (about 405,000) of all cardiovascular disease deaths in the United States, and 42 percent (7.4 million) globally, each year, as reported by the Centers for Disease Control and Prevention.
This is the first published meta-analysis to include cardiac death, also known as coronary mortality, as a primary endpoint, and the most comprehensive review of the evidence to date. The results were announced in an August 23 press release.
The meta-analysis showed a 17 percent risk reduction in groups who had elevated triglycerides or LDL cholesterol. These results are consistent with the hypothesis that EPA and DHA omega-3s may be most useful for reducing cardiac death in higher-risk individuals.
The National Center for Health Statistics estimates that 25 percent of adults in the U.S. have triglyceride levels greater than or equal to 150 mg/dL and 27 percent have LDL cholesterol levels less than or equal to 130 mg/dL (4). The greatest reduction in cardiac death rates, an almost 30 percent risk reduction, was observed in trials that utilized dosages of more than one gram of EPA and DHA per day.
The RCTs reviewed were longer than six months in length, and investigated cardiac death as the primary outcome, comparing frequencies of cardiac death events between the omega-3 and control groups. The researchers reviewed studies published through December 2016 that included both dietary supplement and pharmaceutical omega-3 interventions. In the omega-3 groups, 1,613 cardiac deaths were recorded (4.48 percent of subjects) compared to 1,746 cardiac deaths in the control groups (4.87 percent of subjects). This study did not review the effects of EPA and DHA consumption from fish on cardiac death risk because no randomized, controlled trials exist, but observational studies on EPA and DHA from fish also support a benefit in risk reduction.
Consuming sufficient amounts of EPA and DHA is part of eating a well-balanced diet and leading a healthy lifestyle. The Dietary Guidelines for Americans and the American Heart Association recommend consuming seafood and fatty fish each week. Two servings per week supplies 250-500 mg of EPA and DHA per day. In addition, the American Heart Association also recommends one gram of EPA and DHA per day for those with diagnosed heart disease.
Increasing omega-3 intake is easy and inexpensive, with omega-3 supplement costs ranging from $10-$60 per month and fatty fish ranging from $10-$25 per month, depending on the type of fish. Omega-3 are also widely viewed as safe. The U.S. Food and Drug Administration allows up to three grams per day, and the European Food Safety Authority reports no safety issues with up to five grams per day. If consumers are allergic to fish or would like to take higher doses, they should consult their physicians.
A limitation of the results from the present meta-analysis is that several of the studies included were small, or had suboptimal trial designs. For example, two of the largest trials, GISSI-Prevenzione and JELIS, were controlled but did not utilize placebos. While this does raise the possibility of bias or confounding, this is less likely to be a concern with a fatal outcome, and removing individual studies from the analysis did not result in any changes in findings. Additionally, baseline and post-intervention omega-3 levels were not available in most studies, making it difficult to determine how much of an increase in blood levels actually occurred through supplementation.
The meta-analysis was funded by the Global Organization for EPA and DHA Omega-3s (GOED), but GOED was not involved in the design or interpretation of the results.