Daily supplementation with marine-derived omega-3 fatty acids has been promoted for its potential health benefits in cardiovascular diseases.
Multiple randomized trials were performed, though study power was somewhat limited. A recent meta-analysis from the University of Oxford for the Omega-3 Treatment Trialists’ Collaboration suggested that daily omega-3 fatty acids does NOT significantly reduce the rate of fatal or nonfatal coronary heart disease or any major vascular events in high-risk individuals.
This meta-analysis pooled 10 randomized trials following 77917 participants with prior coronary heart disease or stroke or at high-risk for cardiovascular disease. The analysis included several high-profile trials, such as ORIGIN, JELIS, GISSI-HF, and GISSI-P. Duration of treatment was 4 years on average.
It found that omega-3 fatty acids were NOT associated with
- any coronary heart disease events (RR 0.96, p=0.12)
- nonfatal MI (RR 0.97, p=0.40)
- coronary heart disease death (RR 0.93; p=0.05)
- major vascular events (RR 0.97, p=0.10)
- stroke (RR 1.03, p=0.56)
- revascularizations (RR 0.99, p=0.61)
Associations of Omega-3 Fatty Acids With Major Vascular EventsThe number of events by allocated treatment are presented for individual trials and subgroups of trials; participants can contribute only once to subtotals and totals of major vascular events. Rate ratios for individual trials or subgroups of trials are indicated by squares and 99% CIs by horizontal lines. Overall totals and their 95% confidence intervals are represented by diamonds. The size of the squares and the diamonds are proportional to the statistical information conveyed.
In view of the fact that many patients who oppose many therapies are very happy to take supplements like omega-3 fatty acids, the lack of benefit does raise some caution over its use, despite its low cost and generally accepted safety profile.
Two large ongoing trials, VITAL in the US and ASCEND in the UK, will provide additional evidence on the effects of omega-3 fatty acids in a further 40000 patients. In particular, these trials enrolled patients in primary prevention setting, at lower risk of cardiovascular diseases, who may be less likely to be confounded by concomitant use of medications such as aspirin and statins, as in the higher-risk secondary prevention settings.
Aung et al. Associations of Omega-3 Fatty Acid Supplement Use With Cardiovascular Disease Risks: Meta-analysis of 10 Trials Involving 77 917 Individuals. JAMA Cardiology 2018. https://jamanetwork.com/journals/jamacardiology/fullarticle/2670752
Author: Andrew To