HealthNotes

• By Suzanne Dixon, MPH, MS, RD

Do Omega-3 Fats Support Heart Health?

A review of existing research and reanalysis of certain studies on omega-3 fats and heart health has resulted in a surprising finding: The review calls into question the long-standing positive association between heart health and fish oil supplementation. The focus of the analysis was omega-3 supplements rather than dietary sources.

Researchers found that omega-3 fat supplementation was not associated with a lower risk of all-cause mortality

Fishing for better health

In this study, heart and vascular health was measured by longevity: death due to any cause (all-cause mortality), cardiac death, or sudden death due to heart disease, heart attack, and stroke. Researchers pooled results from 20 previous studies of a total 68,680 adults in a statistical method called meta-analysis. All of the studies included in the meta-analysis were clinical trials in which some of the participants were given omega-3 fat supplements and others were given a placebo (containing no omega-3s).

Researchers found that omega-3 fat supplementation was not associated with a lower risk of all-cause mortality, cardiac death, sudden death, myocardial infarction, or stroke. For all of the conditions other than stroke, the results trended in the direction of fish oil supplements protecting against cardiovascular disease, though these results weren’t statistically significant. For stroke, the result trended in the direction of suggesting more harm than benefit from omege-3 fat supplements, though again, results were not statistically significant.

Putting results in context

Why do omega-3s have a heart-healthy reputation? While the results of the meta-analysis demonstrate that the relationship between fish oil and heart health is more complicated than previously thought, keep in mind that, among other heart-related benefits, fish oil has been shown to reduce high blood pressure and high triglycerides, both considered markers for heart disease risk. And studies have consistently associated fish-rich diets, such as the Mediterranean-style diet, with better cardiovascular health.

It should also be considered that of the 3,635 studies assessed, just 20 made the cut for the meta-analysis. Studies are often eliminated because a study's design makes it difficult to compare with other studies, but they may still be relevant to the larger question of a supplement's efficacy. Of the more than 3,600 other studies on omega-3 fat that were not included in the review, many support health benefits of taking omega-3 fat supplements.   

Cutting through the confusion

So what’s a health-conscious consumer to do? Before deciding whether or not omega-3 supplements are right for you, ask yourself some of these questions:

• Why would I want to boost omega-3s? Omega-3s have shown positive effects in other conditions, including hypertension, anxiety, depression, eczema, asthma, rheumatoid arthritis, lupus, and Crohn's disease. If heart disease is your concern, talk to your doctor about all of the things you can do to reduce risk. Omega-3 supplements may have a place in your heart health plan, but exercising and eating right are the more important first-line defenses everyone should consider.
• What are the downsides of supplementing omega-3s? This study found a trend toward increased risk of stroke in people taking omega-3 supplements—because the results were not statistically significant, however, it’s not clear, based on this study, what recommendations should be made.
• What are the downsides of not getting enough omega-3s? People take omega-3 supplements for a variety of reasons. If you feel omega-3 supplements provide some health benefit, it may be worth it to keep taking them. Ask your doctor if you’re uncertain.
• Can I get omega-3s from food? In addition to cold-water fish—such as salmon, sardines, halibut, pollock, and cod—plenty of foods contain omega-3 fats, including flaxseeds, chia seeds, walnuts, and other nuts and seeds. Though most of the evidence showing EPA-DHA benefit has been with fish oil, there are other health benefits of including plant sources of omega-3 fats.

(JAMA 2012;Vol 308:1024–33)