Death by heart attack: Omega 3 EPA and DHA supplements reduce risk by 8 percent

Consumption of omega-3 dietary supplements or pharmaceuticals reduces the risk of cardiac death by 8 percent. This is as high as 17% in individuals with high cholesterol or triglycerides, and up to 30% in those following supplementation with more than one gram per day of EPA and DHA. Data suggesting that omega-3 supplements may be an effective and side-effect-free strategy for the prevention of heart disease and sudden cardiac death.

This was discovered by scientists at Midwest Biomedical Research and Johns Hopkins University (USA) through research, which collectively analyzed the results of numerous studies, recently published in the Journal of Clinical Lipidology.

Cardiovascular risk and omega-3: a long-studied relationship

Cardiovascular diseases are the leading cause of mortality and disability in Western countries. Their prevalence is due to both pathological conditions and the spread of unhealthy lifestyles. The definition of cardiovascular diseases includes all those affecting the heart and blood vessels. The most common are myocardial infarction, angina pectoris, cardiomyopathies, heart failure, arrhythmias, and stroke. Sudden cardiac death, defined as death that occurs from cardiac causes, with sudden loss of consciousness within 1 hour of symptom onset, accounts for 50% of all deaths from cardiovascular disease. Most population-based studies conducted in industrialized countries have shown that the risk factors for sudden cardiac death are the same as for coronary artery disease; and they include older age, male sex, familiarity, increased LDL cholesterol levels, hypertension, smoking, and diabetes mellitus. The relationship between a diet rich in fish containing omega-3 fatty acids and protection from cardiovascular disease has been confirmed by many studies in recent decades. The mechanisms by which omega-3 exert protective effects at the cardiovascular level are diverse, they in fact increase the fluidity of cell membranes, improve endothelial function, modulate platelet aggregation, have an antiarrhythmic function, and help reduce blood triglycerides.

EPA and DHA reduce the risk of cardiac death by 8 percent

During the meta-analysis study, researchers collected data from more than 70,000 people and compared the frequencies of cardiac death events between subjects who consumed omega-3s as supplements or as drugs and control subjects who did not use them. The results showed that omega-3s could reduce the risk of cardiac death by an average of 8 percent. This percentage, in subjects who had high levels of triglycerides or bad cholesterol was even higher (amounting to 17 percent). 

Consumption of EPA and DHA was even found to be associated with a 30 percent decrease in the risk of cardiac death, in people who had consumed dosages greater than 1 gram of omega-3 per day. "Importantly, these results agree with the findings of the recent American Heart Association scientific advisory, which states that treatment with EPA and DHA can reasonably be a strategy for the prevention of coronary heart disease and sudden cardiac death," said Dr. Kevin Maki of Midwest Biomedical Research, lead author of the study. "A significant advantage of supplementation with EPA and DHA is the low risk associated with their use. Because of the low likelihood of side effects, even a modest benefit is clinically significant," the researcher continued. 

Commenting independently on the results of the meta-analysis, Bruce Holub, professor emeritus at the University of Guelph, pointed out that they suggest that most adults could be protected from sudden cardiac death by increased consumption of foods rich in EPA and DHA. The study also showed that the benefits of omega-3 supplementation are greatest in regions where consumption of omega-3-containing fatty fish is low, as is the case, for example, in North America where the average intake of EPA and DHA per person is only 110-150 milligrams per day. The study does not elucidate, however, the mechanism of action by which omega-3s may reduce the risk of cardiac death, but according to the researchers, dosages above one gram of EPA and DHA may be necessary to produce clinically relevant changes on the mechanisms of inflammation and thrombosis. 

Dr. Harry Rice, vice president of regulatory and scientific affairs for the Organization for EPA and DHA (GOED), which commissioned the research, welcomed the study's findings, stressing the importance of a finding concerning the effects of EPA and DHA on cardiac death. Indeed, numerous studies in recent years have highlighted the role of omega-3s in combating cardiovascular disease, but according to Rice, to understand their role on the cardiovascular system, research must focus on a specific condition, as this meta-analysis does. The study is the first of its kind to include cardiac death as a primary outcome of treatment and the most comprehensive review on the topic conducted to date.

Some significant details of the research

As many as 14 studies, published by December 2016, with a total of 71,899 subjects involved were reviewed during the search. The selection of included studies was conducted using major databases of scientific articles and selecting publications that had investigated the effect of omega-3 supplements and drugs, over an intervention period of at least 6 months, on the outcome of cardiac death. 

Among the subjects analyzed, those who had followed omega-3 supplementation died of cardiac causes were 1613, while those in the control group (without supplementation) were 1746. The authors did not examine the effects of EPA- and DHA-rich fish consumption on the risk of cardiac death, due to a lack of studies. However, the available data still support the hypothesis of the ability of a fish-rich diet to reduce mortality.

Omega-3s as a future pharmacologic?

According to the researchers who conducted the meta-analysis, the data obtained suggest the efficiency of omega-3s in reducing the risk of cardiac death, and the need for further research to evaluate the potential risk reduction with omega-3 supplementation at high dosages and in populations with a higher likelihood of mortality. 

Future investigations should include assessment of omega-3 markers before supplementation and during treatment, and be designed to test the mechanisms by which EPA and DHA may act. Four studies are currently underway on the risk of cardiovascular events following treatment with omega-3 supplements, which will provide useful additional information on their hypothetical use as drug therapy. 

Source: K.C. Maki et al. "Use of supplemental long-chain omega-3 fatty acids and risk for cardiac death: An updated meta-analysis and review of research gaps." Journal of Clinical Lipidology.