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What are Omega-3 Fatty Acids?

Contributors: Sarah Klemm, RDN, CD, LDN

Published: March 01, 2022

Reviewed: February 18, 2022

What are Omega-3 Fatty Acids
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Research shows that eating two 4-ounce servings of seafood per week may reduce 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 essential fatty acids. But omega-3s are not limited to fish and seafood. 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). Research suggests people who eat fatty fish and other seafood as part of a healthy dietary pattern have lower risk of heart problems and lower risks of chronic disease. This has been seen in people with and without a history of heart disease, though evidence is stronger for the benefits of omega-3 fatty acids in people with a history of heart disease. For instance, if you have high blood triglycerides, consuming omega-3 fatty acids 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. Here are tips for getting more plant-based omega-3s:

  • Include oils that contain omega-3 fatty acids, such as flaxseed oil, walnut oil, canola oil or soybean oil.
  • Add hemp hearts or ground flaxseed to cereals, yogurt and salads. The body isn't able to break down whole flaxseeds but grinding them before use helps with absorption.
  • Substitute ground flaxseed for part of the butter or oil when baking. Use 3 tablespoons of ground flaxseed mixed with 1 tablespoon of water to replace 1 tablespoon of oil.
  • Snack on edamame or walnuts for a snack that provides omega-3 fatty acids.

Omega-3 Supplements

Omega-3 supplements may be beneficial in combating heart disease, though some studies have challenged if taking supplements is as effective as consuming food sources. Scientific evidence describing the advantage of omega-3 supplements on heart disease risk for people who don't actually have heart disease is limited. Consult a registered dietitian nutritionist 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 U.S. Food and Drug Administration advises consuming no more than 3 grams of EPA and DHA omega-3 fatty acids per day from foods and dietary supplements, unless prescribed by a health care provider. Taking too much may cause uncomfortable gastrointestinal symptoms. And, although small, there is a risk of increased bleeding when people who take anti-platelet agents or anticoagulants also take high doses of omega-3 fatty acids.

The omega-3 fatty acid content of fish varies. Higher amounts are typically found in sources such as herring, salmon, sardines and trout. Mackerel is a rich source of omega-3 fatty acids, however, one variety known as king mackerel is also high in mercury and the FDA advises individuals who are pregnant or nursing and young children to avoid this fish. Atlantic mackerel and Pacific chub mackerel are lower mercury alternatives.

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.

Finally, ask your doctor or a registered dietitian nutritionist to determine if 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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