Omega-3 fatty acid supplements often contain both EPA and DHA.

Higher levels of eicosapentaenoic acid (EPA) in the blood lower the risk of serious cardiac events and death in patients, although docosahexaenoic acid (DHA) reduces the cardiovascular benefits of EPA, according to a study at the American College of Cardiology 2021 scientific meeting. Omega-3 fatty acid supplements often contain both EPA and DHA. According to the researchers, higher DHA levels at each EPA level worsened health outcomes.

The study examined 987 patients over a period of 10 years using the INSPIRE registry, an Intermountain Healthcare database launched in 1993 with more than 35,000 blood samples from nearly 25,000 patients. The patients analyzed underwent their first documented coronary angiographic study at Intermountain Healthcare between 1994 and 2012. Circulating levels of EPA and DHA in their blood were measured from these samples. During the 10 years of the study, the researchers tracked participants and looked for serious cardiac side effects, including heart attack, stroke, or heart failure that required hospitalization or death.

The study also found that patients with higher levels of DHA than EPA were at higher risk for heart problems.

“The advice to take omega-3s for the benefit of your heart is widespread, but previous studies have shown that science does not confirm this for every single omega-3 system,” said Viet T. Le, MPAS , PA, investigator and cardiovascular physician assistant at the Intermountain Heart Institute in a press release. “Our results show that not all omega-3s are created equal, and that EPA and DHA together, as often found in dietary supplements, can negate the benefits that patients and their doctors are hoping for.”

According to the researchers, these results raise concerns about the combined use of EPA and DHA, particularly through dietary supplements.

“Based on these and other findings, we can still tell our patients to eat foods rich in omega-3s, but we shouldn’t recommend them in pill form as dietary supplements or even as combined (EPA + DHA) prescription products,” said Le in the release. “Our data reinforce the results of the recent REDUCE-IT (2018) study that EPA prescription products reduce cardiac events.”


New study finds that the combination of omega-3 fatty acids in popular diet supplements can interfere with heart benefits [news release]. EurekAlert; May 17, 2021. Accessed May 17, 2021.


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