A review of recent neutral studies questioning the benefits of omega-3s for heart health suggests that the findings may have been due to a number of design issues, rather than a lack of substantiated clinical benefits in cardiovascular disease. The issues include such things as:
- aggressive cardiovascular drug treatment overshadowing the benefits of long-chain omega-3s
- high background long-chain omega-3 intake at study initiation
- too few subjects in the study
- treatment duration too short
- insufficient LC omega-3 dosage
- increase in omega-6 fatty acid intake during the study
- failure to assess the LC omega-3 status of the subjects prior to and during treatment
- lack of clarity concerning which mechanisms were expected to produce benefits
The existing body of gold-standard research showing omega-3s may reduce cardiovascular death risk, maintain healthy blood pressure and improve triglyceride levels also makes it difficult to conclude that EPA and DHA consumption does not contribute to a healthy heart.
http://www.eurekalert.org/pub_releases/2016-02/g-phb012916.php
Rice, H. B., Bernasconi, A., Maki, K. C., Harris, W. S., von Schacky, C., & Calder, P. C. (2016). Conducting omega-3 clinical trials with cardiovascular outcomes: Proceedings of a workshop held at ISSFAL 2014. Prostaglandins, Leukotrienes and Essential Fatty Acids (PLEFA), 107, 30–42. http://doi.org/10.1016/j.plefa.2016.01.003