Omega-3 Fatty Acids

Omega-3 fatty acids are polyunsaturated fats. There are three main omega-3 fats, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA).

Not all omega-3 fatty acids act the same way in the body. ALA is necessary for normal growth and development, a healthy nervous system, and skin health. EPA and DHA are more closely related to supporting heart health. Although similar heart-healthy benefits are proposed for ALA, its beneficial effects are less certain. The body is capable of making EPA and DHA from ALA, but the conversion rate is relatively low.
As part of cell membranes, the barriers that separate and protect the inner workings of cells from their environment, omega-3s offer structural support. DHA is especially important for brain development during pregnancy and early childhood and is found in high levels in the brain and in the cells of the retina, the part of the eye that registers images and transmits them to the brain for processing.
Omega-3s also serve as the raw materials for making compounds that are critical to proper blood clotting, helping arteries to relax and contract properly, and regulating inflammation in the body. Most substantial evidence for the beneficial effects of EPA and DHA concerns heart health.

If you’re in your childbearing years and are capable of becoming pregnant, or you’re pregnant or breastfeeding, eating seafood is a good idea, as long as that seafood is on the safe side. The level of mercury, toxic to a developing brain and nervous system, in seafood is the main safety concern. Mercury builds up in the body, and it’s possible to pass it to your unborn child during pregnancy and when nursing. The U.S. Food and Drug Administration (FDA) warns women against eating the following higher-mercury fish during their childbearing years to reduce the risk of mercury poisoning to themselves and their children: shark, swordfish, king mackerel, and tilefish.

Despite the warnings about seafood, experts say the benefits far outweigh the risks. In fact, the 2010 DGA advises pregnant and breastfeeding women to eat eight to 12 ounces of seafood weekly. *

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How much do I need?
 
The 2010 Dietary Guidelines for Americans (DGA) suggest that adults eat at last eight ounces of fish weekly, which provides an estimated average of 250 milligrams (mg) of EPA and DHA combined a day.
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EPA and DHA are found in varying amounts in an array of seafood such as shrimp, scallops, clams, tilapia, cod, and salmon. ALA is found in plant foods such as flax seeds, walnuts, and canola oil. Flaxseed oil is a rich source of ALA.

Always talk with your doctor before taking any omega-3 supplements, including those that contain ALA only. People with allergies or hypersensitivity to fish should avoid fish oil or omega-3 fatty acid products derived from fish. Algal oil supplements may be a good option for those who are allergic to fish and for vegetarians.

Gas and indigestion are among the most common side effects. In very high doses, EPA and DHA increase the risk of inappropriate bleeding in the body, although there is little evidence of significant bleeding risk at lower doses. People with bleeding conditions, and those who take anticoagulant medications, which increase bleeding, need to speak with their doctor or pharmacist before using any omega-3 supplements.

If you’re in your childbearing years and are capable of becoming pregnant, or you’re pregnant or breastfeeding, eating seafood is a good idea, as long as that seafood is on the safe side. The level of mercury in seafood – since it is toxic to a developing brain and nervous system – is the main safety concern.

The U.S. Food and Drug Administration (FDA) warns women against eating the following higher-mercury fish during their childbearing years to reduce the risk of mercury to themselves and their children: shark, swordfish, king mackerel, and tilefish.

  1. Natural Standard. Professional Monograph. Omega-3 Fatty Acids, Fish Oil, Alpha-Linolenic Acid. http://naturalstandard.com/databases/herbssupplements/fishoil.asp.

  2. United States Department of Agriculture, Center for Nutrition Policy and Promotion. Dietary Guidelines for Americans, 2010. http://www.cnpp.usda.gov/DGAs2010-PolicyDocument.htm.

  3. American Heart Association. Fish and Omega-3 Fatty Acids. http://www.americanheart.org/presenter.jhtml?identifier=4632

  4. Kris-Etherton PM, Harris WS, Appel LJ. Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease. Circulation. 2002;106:2747-2757. http://circ.ahajournals.org/cgi/content/full/106/21/2747

  5. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: National Academies Press; 2002.

  6. United States Department of Agriculture. Agricultural Research Serving. Nutrient Data Laboratory. http://www.ars.usda.gov/main/site_main.htm?modecode=12-35-45-00.

Satisfying the suggested intakes for EPA and DHA through food is preferable. However, if you don’t eat fish, those quotas will be next to impossible to achieve, and you may need to rely on dietary supplements. Fish oil supplements contain EPA and DHA. Fish derive DHA from the algae they eat, and algal oil supplements are rich in DHA only. (The body can make EPA from DHA.) Algal oil supplements and may be a good option for those who are allergic to fish and for vegetarians.

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