Results from a new study published in the Journal of Clinical Lipidology showed that in 14 randomized, controlled trials (RCTs) of 71,899 people, consumption of EPA and DHA omega-3s reduced the risk of cardiac death by a statistically-significant average of 8 percent. 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. 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 meta-analysis showed even greater—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 (see table), which is important since The National Center for Health Statistics estimates that 25 percent of adults in the US have triglyceride levels ≥150 mg/dL and 27 percent have LDL cholesterol levels ≥130 mg/dL (4). The greatest reduction in cardiac death rates—an almost 30% risk reduction—was observed in trials that utilized dosages of more than 1 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.