The trial was an ancillary study of the Age-Related Eye Disease Study 2 (AREDS2), which includes 4203 men and women treated at US ophthalmology clinics. As part of the factorial-design randomized trial, individuals were treated with 350-mg docosahexaenoic acid and 650-mg eicosapentaenoic acid (EPA) for 4.8 years. Approximately 20% of randomized participants had a history of CVD. Participants were also treated with the macular xanthophylls lutein and zeaxanthin to determine impact on CV outcomes.
Regarding the primary end point, a composite of CV mortality and morbidity, supplementation with omega-3 fatty acids failed to provide any reduction in clinical events. In terms of secondary end points, which included multiple combinations of components of the primary end point, there was also no reduction in events. In an exploratory analysis, the researchers did not observe any significant difference in clinical-event rates among those with high or normal triglycerides. Supplementation with lutein and zeaxanthin also failed to reduce CV morbidity and mortality.
The FDA has approved omega-3 fatty acids for hypertriglyceridemia, and the European Medicines Agency has approved them as adjuvant treatment in post-MI patients. However, their use for CV-risk modification remains controversial.
A number of comments from editorialists pointed out that the present study was likely underpowered to detect a significant benefit in CV outcomes because the researchers assumed a 25% reduction in the primary end point. The current study, they add, is just one of countless others that continue to test the link between supplementation with omega-3 fatty acids and CV risk. Given these and other results, patients should be informed of the uncertainty surrounding the effect of omega-3 fatty acids on heart health and instead encouraged to regularly consume whole fish. What is evident so far is that omega-3 supplementation with daily doses close to 1 g in patients with or without established CVD shows no clear, considerable benefit.
- Taking omega-3 fatty-acid supplements for nearly five years failed to reduce the incidence of CVD mortality
- The FDA has approved omega-3 fatty acids for hypertriglyceridemia, not for the prevention of CVD
- Patients should be told of the uncertainty preventing CVD with the taking of the Omega-3 supplements
Writing Group for the AREDS2 Research Group. Effect of long-chain omega-3 fatty acids and lutein/zeaxanthin supplements on cardiovascular outcomes. JAMA Intern Med 2014; DOI:10.1001/jamainternmed.2014.328. Published March 17, 2014 in JAMA Internal Medicine Abstract