What are Omega-3 Fatty Acids?

Reviewed by Sharon Denny, MS, RDN
Omega-3 Fatty Acids

Research shows that eating two 4-ounce servings of seafood per week reduces the risk of heart disease and related deaths. Many health professionals attribute this potentially life-saving quality of seafood to the presence of omega-3 fatty acids. And, omega-3s are not limited to fish. They are also found in some vegetable oils, nuts, seeds and soy foods.

Fish contain two important omega-3 fatty acids: EPA (eicosapetaenoic acid) and DHA (docosahexaeonic acid). Although the research is limited, studies show that in patients with known heart disease, higher blood levels of DHA and EPA are associated with a reduction in arrhythmias (irregular heart beat) and fatal heart disease. However, the benefit of eating fish is not clear for those without known heart disease. If you have high blood triglycerides, omega-3 supplements may help lower your levels.

Plant-Based Omega-3s

Some plants also contain an omega-3 fatty acid known as ALA (alpha-linolenic acid). You can find it in various oils, nuts, seeds, beans and other sources. Although research is limited, higher intakes of ALA have been shown to reduce risk of heart disease in both those with and without heart disease. Here are tips for getting more omega-3 fatty acids:

  • Use moderate amounts of vegetable oils such as canola oil, soybean oil, flaxseed oil and walnut oil.
  • Add walnuts or ground flaxseed to cereals, yogurt and salads. Whole flaxseeds will not work as well — they simply pass through the body undigested.
  • Substitute ground flaxseed for butter or oil when baking. Use 3 tablespoons of ground flaxseed instead of 1 tablespoon of oil.
  • Nibble on an omega-3 fatty acid-rich snack such as edamame or steamed soybeans, which are sold fresh or frozen.

Omega-3 Supplements

Omega-3 supplements may be beneficial in combating heart disease. Studies actually show a 45-percent reduction in sudden death in people with heart disease who took EPA or DHA supplements. For some, however, there was no effect. Interestingly, there is no scientific evidence describing the advantage of omega-3 supplements on heart disease risk for people who don't actually have heart disease. Consult a doctor to determine if you would benefit from an omega-3 supplement.

Too Much Omega-3?

Given the fact that many of our foods are fortified with omega-3 fatty acids, it is possible to get excess amounts of it if you take additional supplements. The Food and Drug Administration (FDA) advises that consumption of more than 3 grams of omega-3 fatty acids per day may cause uncomfortable gastrointestinal symptoms. And, although small, there is a risk of increased bleeding possible when people who take anti-platelet agents or anticoagulants also take 3 to 4 grams of EPA and DHA.

Something else to consider is that certain fish are high in mercury. The FDA and Environmental Protection Agency advise women who may become pregnant, pregnant women, nursing mothers and young children to avoid shark, swordfish, king mackerel and tilefish, and limit albacore tuna to 6 ounces per week.

In summary, remember to feast on fish at least twice a week and regularly include omega-3-rich plant sources — such as flaxseeds, chia seeds and walnuts — in your diet.

Finally, ask your doctor or a registered dietitian nutritionist to determine whether — and at what amount — an omega-3 fatty acid supplement would be helpful for you. Omega-3 fatty acid supplements should not be taken without a physician's supervision.

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