All omega-3 fatty acids offer protective benefits to the heart, including making the blood less likely to clot and cause a heart attack, protecting against irregular heartbeats that cause sudden cardiac death, and decreasing risk of cardiovascular disease (CVD).

Two especially beneficial omega-3 fats -- eicosapentaenoic and docosahexaenoic acids (EPA and DHA) -- are found in fish. A less potent omega-3, alpha-linolenic acid, is found in plant sources such as soybeans, canola, walnut and flaxseed.

The American Heart Association’s (AHA) dietary guidelines have recommended that adults eat at least two servings of fish per week. However, in light of the recent Environmental Protection Agency and Food and Drug Administration (FDA) warning about the presence of contaminants in some species of fish, a report examined the benefits and risks of consuming omega-3 fats from this source.

The report stated that benefits and risks depend largely on a person’s life stage. For example, children and pregnant and nursing women are more susceptible to mercury from fish so it would be more important for them to avoid eating fish than for middle-aged and older men, and postmenopausal women, for whom the benefits of eating fish are thought to outweigh the risks.

Additionally, people with elevated triglycerides, an indicator for heart disease, may benefit from taking 2 to 4 grams of EPA and DHA per day as a supplement, according to the report. A 1 gram per day dose, which may be more than can be received from diet alone, is currently recommended for patients with existing CVD. The report noted, however, that high intakes of EPA and DHA could cause excessive bleeding in some people.

Circulation November 19, 2002;106(21):2747-57

Current Atherosclerosis Report November 2002 (6):412-3