Eating fish is healthier than fish oil supplements

Fish oils are rich in omega-3 fatty acids, a kind of “healthy fat.” The protective effect of omega-3 fatty acids may stem from several different effects they have on the body. They keep platelets from forming clots in the blood. They help reduce blood pressure. They raise HDL, the so-called “good cholesterol.” They lower levels of another kind of fat linked to heart disease and strokes: triglycerides. Probably most important, they seem to prevent lethal heart-rhythm disorders from developing.

So since heart disease is such a common problem, I recommend that most people have at least two servings per week of oily fish. That’s true even if they don’t have heart disease or family members with heart disease.

I can’t be as certain about the value of taking fish oil supplements. The evidence that fish oils are heart-healthy comes mainly from studies of eating fish, not from swallowing fish oil capsules. However, there is reasonably strong evidence that fish oil supplements may reduce the risk of sudden death from heart disease. And they have no significant side effects.

So if you are a person that does not like to eat fish, and since heart disease runs in your family, I’d advise you to take fish oil supplements.

The heart benefits of fish and of fish oil supplements appear to be mainly on reducing the risk of sudden death.

The evidence is not as strong that fish and fish oil reduce the risk of other heart conditions, like angina or heart attacks. I think that is probably because they are potent in reducing the heart rhythm disorders that can suddenly cause the heart to stop beating.

Typical over-the-counter fish oil supplements contain eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA), the omega-3s found in fish. Many authorities recommend that if you already have heart disease or high levels of triglycerides, you should discuss with your doctor taking 3,000 milligrams of fish oil capsules per day. If you have elevated triglycerides, your doctor may recommend a higher dose (or some other treatment to lower triglycerides).

As beneficial as fish oil capsules may be, I prefer to get nutrients from foods rather than supplements. That’s because whole foods often have other nutrients that may also be good for your health. Fatty fish such as salmon, mackerel, herring and sardines are especially good food sources of omega-3s. I eat fish at least once or twice a week — but that’s not hard because I love fish!

(This column is an update of one that ran originally in December 2013.)

(Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.)