The science of EPA/DHA for heart health

Research articles on the cardiovascular benefits associated with the long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are published almost daily. While most report positive results, the ones reporting neutral results (i.e., no benefit) seem to garner the most attention from the media. In the last two years, conclusions among meta-analyses looking at omega-3s and coronary heart disease (CHD) outcomes have been inconsistent, but a closer look suggests much is left to the interpretation of the results. For the last 10+ years, the benefit of omega-3s on CHD/cardiac death has been consistently reported.

In 2016, the U.S. Agency for Healthcare Research and Quality (AHRQ) published “Omega-3 Fatty Acids and Cardiovascular Disease: An Updated Systematic Review” with mixed findings (Balk et al. 2017). While most of the findings in the 1,000+ page report were not unexpected, it was a surprise that the authors concluded there was a low strength of evidence of no association of EPA/DHA and CHD death. Curiously, this was based on only five RCTs reporting on cardiac death (combined CHD and other cardiac death) and no statistics were provided. When the Global Organization for EPA and DHA Omega-3s (GOED) ran the statistics, it found a 17 percent risk reduction, but it just missed statistical significance, which was most likely due to a lack of power. While there was pre-specified inclusion and exclusion criteria applied, the criteria may have missed some studies given its “arbitrary” nature. More specifically, the authors stated, “Due to the very large number of potentially eligible studies (more than 400), we applied arbitrary thresholds based on sample size, follow-up duration, and whether subgroup or interaction analyses were reported.” Had a scientifically substantiated threshold been chosen, additional studies may have been included, resulting in increased power and statistically significant results.

This is an excerpt from the article, “EPA/DHA Cardiovascular Science Update.” To read the complete article, download INSIDER’s Heart Health digital magazine.