Related Media: Choosing the Right Fats and Carbohydrates

Health Benefits of Omega-3s

There is some evidence that suggests that omega-3s may:

• Decrease the risk of heart disease. In one study, people who replaced saturated fats with PUFAs had fewer coronary events (eg, heart attacks) and fewer deaths due to heart disease. Other studies have suggested this favorable effect on heart disease may be due to the ability of omega-3s to:
  • Lower elevated triglyceride levels —High triglyceride levels can contribute to coronary heart disease.
  • Decrease the risk of arrhythmia, an abnormality in the rhythm of the heart that can sometimes be life-threatening—Note that the evidence here is contradictory, and there is even some suggestion that omega-3s could increase the risk of harmful arrhythmias in some people. Talk to your doctor before using supplements for this purpose.
  • Reduce the blood's tendency to clot—Although blood clotting is a life-saving process in response to a cut or similar trauma, blood clots that occur inside intact blood vessels can contribute to the clogging that occurs with atherosclerosis. By decreasing the tendency to clot, omega-3s make blood thinner and able to flow more easily, which may decrease the risk of heart attack and stroke.
• Reduce the inflammation involved in conditions like rheumatoid arthritis.
• Improve symptoms of depression and other mental health disorders in some individuals, though the evidence is quite limited.

While many of these benefits are probably real, more research is needed to confirm some of the health effects associated with omega-3s. Omega-3s almost certainly have significant benefits on heart health. Sources of omega-3s—fish, nuts, seeds, green leafy vegetables—should be an important part of everyone's diet.

Where You Can Find Omega-3s

Fatty fish is the main source of omega-3 fatty acids. Eating a lot of fish also takes the place of foods rich in saturated fats. A good target for omega-3s is 1 to 2 grams daily. Remember though that some fishes contain significant amounts of mercury and may be harmful if eaten in excess.

For example, while albacore tuna is an excellent source of omega-3s, the FDA recommends eating no more than six ounces weekly because of its mercury content. King mackerel should not be eaten at all—despite being an excellent source of omega-3s. Shark and swordfish are also very high in mercury. Fortunately, most of the other fish listed below are sufficiently low in mercury that the FDA recommends up to two six ounce servings weekly while the American Heart Association suggests “at least two servings” of 6-7 ounces. Canned light tuna, crab, pollock, flounder, oysters, and shrimp are relatively low in mercury and provide quite good levels of omega-3s in a 6-7 ounce serving. Omega-3s are also found in: soybean and canola oils, flaxseed, flaxseed oil, walnuts, and leafy green vegetables.