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Omega-3 Fatty Acids

Health Benefits of Omega-3 Fatty Acids


Updated June 04, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Omega 3 capsules in jar
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What are Omega-3 Fatty Acids?

Omega-3 fatty acids are important for a number of functions in the body. These functions include:

  • relaxation and contraction of muscles
  • blood clotting
  • digestion
  • fertility
  • cell division
  • growth
  • movement of calcium and other substances in and out of cells

Sources of Omega-3 Fatty Acids

Widely available in dietary supplement form, omega-3s are found naturally in certain foods. Oily fish (such as salmon and mackerel), for instance, contain the omega-3s docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Some nuts (such as English walnuts) and vegetable oils (including flaxseed, canola, and soybean), meanwhile, contain an omega-3 called alpha-linolenic acid (ALA).

Health Benefits of Omega-3 Fatty Acids

Research suggests that intake of omega-3 fatty acids may offer the following benefits:

1) Heart Health

Increasing levels of DHA and EPA (either by eating fish or taking fish oil supplements) has been found to improve a number of cardiovascular disease risk factors. For example, studies show that omega-3 intake may lower cholesterol, slightly lower blood pressure, slow the progression of atherosclerosis (hardening of the arteries), and reduce risk of heart attack, stroke, and death among people with cardiovascular disease.

2) Rheumatoid Arthritis

Regular intake of fish oil supplements may reduce morning stiffness, number of swollen joints, and need for corticosteroid drugs in people with rheumatoid arthritis. Fish oil's anti-inflammatory effects may be key to its role in the treatment of rheumatoid arthritis, according to a research review published in 2003.

More Benefits of Omega-3 Fatty Acids

A number of studies have shown that omega-3s may also be beneficial for people with the following health problems. However, the National Center for Complementary and Alternative Medicine cautions that more research is needed before conclusions can be drawn about the use of omega-3s in treatment of these conditions.

Omega-3 Fatty Acids and Cancer Prevention

Several population studies indicate that dietary intake of omega-3 fatty acids may lower your risk of developing certain types of cancer (including cancer of the breast, colon, and prostate). However, randomized controlled trials need to be conducted before scientists can draw any conclusions about the anti-cancer effects of omega-3s.

Are Omega-3 Supplements Safe?

In high doses, fish oil can interact with certain medications, including blood thinners and drugs used for high blood pressure.

If you're considering the use of omega-3 fatty acids in treatment of a chronic health problem, make sure to consult your physician before you start taking a supplement. If you are pregnant or nursing a child, or if you are considering giving a child a dietary supplement, it is especially important to consult your health care provider.

Side Effects of Omega-3 Fatty Acids

Although omega-3 supplements are generally considered safe when taken at low-to-moderate doses, they may cause the following symptoms in some cases:

Fishy aftertaste is a common effect of fish oil supplements.


Calviello G, Serini S, Piccioni E. "n-3 polyunsaturated fatty acids and the prevention of colorectal cancer: molecular mechanisms involved." Curr Med Chem. 2007;14(29):3059-69.

Cleland LG, James MJ, Proudman SM. "The role of fish oils in the treatment of rheumatoid arthritis." Drugs. 2003;63(9):845-53.

de Deckere EA. "Possible beneficial effect of fish and fish n-3 polyunsaturated fatty acids in breast and colorectal cancer." Eur J Cancer Prev. 1999 8(3):213-21.

H. Krishna Moorthy and P. Venugopal. "Strategies for prostate cancer prevention: Review of the literature." Indian J Urol. 2008 24(3): 295–302.

National Center for Complementary and Alternative Medicine. "Omega-3 Supplements: An Introduction." NCCAM Publication No. D436
 July 2009.

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