Omega-3 supplements may not guard against heart attack

It's a tenet of today's nutrition advice, like eating whole grains or choosing lean meat: omega-3 fatty acids, found in fatty fish as well as plant sources like walnuts, flaxseeds, canola oil, and kidney beans, are good for your heart and have been shown to prevent heart disease.

Some people just dislike fish, so for years here on this site I and other physicians have recommended that those who sincerely dislike fish take an omega-3 fatty acid supplement as another way to help improve their cholesterol scores and decrease their risk of heart disease. This is considered to be especially important for those who already have coronary heart disease or heart failure: the American Heart Association has specifically recommended the use of omega-3 fatty acid supplements for people with these conditions as part of an overall strategy to prevent further events.

Today's research has me reconsidering that recommendation - at least to some degree.

This article was written by a team of international researchers calling themselves the "Omega-3 Treatment Trialists' Collaboration." They describe their group as "established to conduct a collaborative meta-analysis based on aggregated study-level data obtained from the principal investigators of all large randomized clinical trials of omega-3 FA [fatty acids] supplements for the prevention of cardiovascular disease" and published in the March issue of JAMA Cardiology (2018;3(3):225-234)

The group's reason for existing describes their work quite accurately: the authors pooled the results of 10 randomized trials, all of which included at least 500 people, lasted at least one year, and compared the effects of omega-3 fatty acid supplements with either placebo or no supplements on whether the participants experienced a coronary heart disease event such as heart attack or stroke, whether fatal or nonfatal. In all the 10 studies included over 77,000 men and women and lasted an average of almost 4.5 years, with the participants' average age at the start of each study at about 64 years.

All of the participants in these studies were considered to be at higher risk for one or more reasons: about 2/3 of participants had a history of coronary heart disease, 28% had already experienced stroke, and 37% had diabetes.

The results of their analysis are rather shocking: even in those who would be expected to benefit most from taking omega-3 fatty acid supplements, the authors found that "omega-3 FA [fatty acid] supplementation had no significant association" with the risk of any coronary heart event, from heart attack to stroke.

The authors went so far as to break the participants down into subgroups like sex, history of heart disease or diabetes, cholesterol scores, or those already taking statins (a group of cholesterol-lowering medication), with still no evidence that omega-3 fatty acids affected the risk of coronary heart events of any kind.

What this means for you

By no means should you throw out your omega-3 fatty acid supplements, if you are taking them: the authors do not report any evidence that the supplements increased the participants' risk of coronary heart events. That said, it would appear that your best bet, as with the evidence regarding many other vitamin or mineral supplements, is to consume your omega-3 fatty acids from foods and not in pill form. If you're allergic to fish, omega-3s can also be found most plentifully in walnuts, chia or flax seeds (best if you grind them before eating), canola oil, spinach, and kidney beans.

First posted: April 11, 2018