Taking these supplements might slightly reduce your risk of dying from heart disease, according to a March 2017 scientific advisory from the American Heart Association (AHA) published in Circulation. Supplementing with omega-3s might also help prevent hospitalization if you have heart failure.
But not for preventing heart disease
Conversely, there’s no evidence that omega-3 supplements can prevent a heart attack, stroke, or heart failure in people who don’t have cardiovascular disease.
The AHA found no specific data that support taking supplements for the primary prevention of heart disease. Neither does it recommend that people who have type 2 diabetes, prediabetes, or atrial fibrillation or those who are at high risk of cardiovascular disease take the supplements to prevent heart disease or stroke. The AHA based its findings on lack of evidence or consensus.
A 2002 AHA scientific statement recommended that people with coronary heart disease get at least 1 gram (1,000 milligrams) of omega-3 fatty acids daily, preferably from oily fish.
Because many Americans don’t eat enough fish to get the omega-3s they need, the question has been whether it’s worth taking supplements to help prevent heart disease.
Studies have been conflicted
The new AHA statement aimed to offer Americans and their doctors more specific guidance about omega-3 supplements based on randomized controlled trials—the most rigorous kind of scientific research available.
Two types of omega-3 fatty acids—eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)—are among the best-studied nutrients for cardiovascular health.
Research finds that omega-3s from fish (not supplements) help relax artery walls, prevent blood clots, and bring down inflammation—all major contributors to heart disease and cardiovascular events like heart attacks.
The best sources are from food sources—primarily from fatty fish like salmon, mackerel, herring, lake trout, sardines, and albacore tuna.
Who should take omega-3 supplements?
The AHA statement recommends taking omega-3 supplements if you’ve had a recent heart attack because they could reduce your risk of dying by about 10 percent.
They’re also worth considering if you have heart failure with reduced ejection fraction, meaning your heart’s main pumping chamber can’t disperse enough oxygen-rich blood throughout your body.
The bottom line
The best way to protect your heart with omega-3s is by eating at least two servings of fatty fish weekly. If you don’t have coronary heart disease, supplements are not likely worth the cost.
If you have heart failure or had a recent heart attack and you’re considering supplements, consult with your doctor, especially if you take a blood thinner, as omega-3s may increase its effect.
Though omega-3 supplements are considered safe, they can have mild side effects, such as belching or diarrhea. You can buy the supplements over the counter, but the quality varies widely.
Ask your doctor if a prescription omega-3 product, often used to help lower high triglyceride levels, may be warranted instead.