Omega-3 fatty acids are part of a class of fats called polyunsaturated fatty acids (PUFAs). Unlike saturated fats that are commonly found in non-skim dairy products and beef, PUFAs have been linked to many health benefits, such as protecting your heart and your joints.

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 high in saturated fats. A good target for omega-3s is 5 grams daily. Remember, though, that some fish contain significant amounts of mercury and may be harmful if eaten in excess.

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.

For more information about mercury levels in fish, visit the US Food and Drug Administration's Food Safety website.

Fish or other food sourceOmega-3 content in a 4-ounce serving
Chinook salmon3.6 grams
Sockeye salmon2.3 grams
Albacore tuna2.6 grams
Mackerel1.8-2.6 grams
Herring1.2-2.7 grams
Rainbow trout1.0 grams
Whiting0.9 grams
King crab0.6 grams
Shrimp0.5 grams
Cod0.3 grams
Tofu0.4 grams
Spinach0.9 grams
English walnuts6.8 grams
Wheat germ and oat germ0.7 - 1.4 grams