Omega-3 does not lower cardiovascular risk
Omega-3 fatty acid (FA) supplements do not yield significant cardiovascular benefits, according to a recent meta-analysis, which shows no reduction in fatal or nonfatal coronary heart disease (CHD) or major vascular events following supplementation.
“[T]he results of the present meta-analysis provide no support for the recommendations to use approximately 1 g/d of omega-3 FAs in individuals with a history of CHD for the prevention of fatal CHD, nonfatal [myocardial infarction] or any other vascular events,” said researchers.
A total of 10 trials were included, involving 77,917 participants (mean age 64 years; 61.4 percent male), in whom 12,001 major vascular events were reported. [JAMA Cardiol 2018;3:225-234]
Pooled analysis showed that there was no significant association between the randomization to receive omega-3 FA supplements and the risk of any CHD event (rate ratio [RR], 0.96; 95 percent CI, 0.90–1.01; p=0.12), including CHD death (RR, 0.93; 0.83–1.03; p=0.05) and nonfatal myocardial infarction (RR, 0.97; 0.87–1.08; P=0.40).
Similar null associations were observed between omega-3 FA supplementation and the risk of major vascular events (RR, 0.97; 0.93–1.01; p=0.10), stroke (RR, 1.03; 0.93–1.13; p=0.56) and revascularization events (RR, 0.99; 0.94–1.04; p=0.61).
The findings were robust in subgroup analysis. For instance, omega-3 FA supplementation did not appear to significantly affect the risk of major vascular events in males (RR, 0.97; 0.91–0.94) or females (RR, 0.98; 0.86–1.12), or in individuals <65 years (RR, 1.03; 0.95–1.12) or ≥65 years (RR, 0.92; 0.85–1.00) of age.
Likewise, history of cardiovascular events had no impact on the effect of omega-3 FA supplements. Those with previous CHD (RR, 0.97; 0.91–1.04), stroke (RR, 1.07; 0.95–1.20) or diabetes (RR, 0.97; 0.89–1.07) did not significantly benefit from the supplementation. The same was true for participants with prior statin use (RR, 0.95; 0.88–1.02).
Furthermore, omega-3 FA supplements also had no significant effect on all-cause mortality (RR, 0.96; 0.92–1.01; p=0.16).
The current literature is conflicted when it comes to the effects of omega-3 FA supplements on cardiovascular risk, as are the current dietary recommendations put forth by different professional cardiology organizations, said researchers.
“It is unclear whether differences in inclusion criteria for prior diseases, concomitant use of statins, or other secondary prevention treatments may explain some of the conflicting results of individual trials,” they explained.
For the present meta-analysis, researchers accessed the databases of PubMed and Medline for randomized clinical trials that assessed the effects of omega-3 supplementation on cardiovascular disease risk. Only those with sample sizes of at least 500 participants were eligible for inclusion.
While study-level data were available to the researchers, the study still had some important limitations. Among which were the failure to assess the effects of the treatment by smoking status and the lack of individual-data, which might have provided greater resolution in determining the effects of omega-3 FA supplements, said researchers.