Ask The RD
Question: I know omega-3 fatty acids are good for me and I should include them in my diet, but I keep reading about the different types—EPA, DHA, ALA—and I am very confused. Can you help me sort out the abbreviations and tell me what I should be looking out for?
Answer: Omega-3 fatty acids are essential fatty acids, which means our bodies cannot make them and we must therefore consume them from an outside source, such as a food or a supplement. This is true of all essential nutrients. (On the flip side, our bodies can synthesize nonessential nutrients.)
We need omega-3 fatty acids, which are polyunsaturated fats, to help build cell membranes in the brain and make hormones that regulate inflammation; contraction and relaxation of artery walls; and blood clotting. Consequently, they are associated with protecting us against heart disease and aid- ing healthy brain and eye development.
The good news is that omega-3 fatty acids are found in a variety of foods. Fatty fish (such as salmon, tuna, trout, anchovies and sardines), walnuts, canola oil, flaxseeds and leafy green vegetables all contain the essential nutrient. The issue gets complicated because there are three types of omega-3 fatty acids: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alphalinolenic acid (ALA). EPA and DHA are also known as the marine omega-3s because they are found primarily in fish, while ALA is referred to as the plant omega-3 since it is found almost exclusively in nuts and vegetables.
EPA and DHA are the most biologically active and, as a result, are considered the most valuable (Simopoulos 2002). ALA is still beneficial, but the body must convert it to EPA or DHA before it can provide any sort of benefit. Therefore, obtaining omega-3 fatty acids from fatty fish is considered the gold standard.
Research indicates that the best way to obtain the protective benefits of omega-3 fatty acids is through food sources, not supplements (HHS 2013). But if you cannot eat enough fish, or choose not to, you can still reap the benefits by making sure you include plenty of plant omega-3 sources in your diet.
There is no recommended daily intake for omega-3 fatty acids, but the American Heart Association recommends that healthy adults consume 500 milligrams per day, which works out to at least 2 servings of fatty fish per week.
Simopoulos, A.P. 2002. Omega-3 fatty acids in inflammation and autoimmune diseases.
Journal of the American College of Nutrition, 21 (6), 495-505. HHS (U.S. Department of Health & Human Services). 2013. Seven things to know about omega-3 fatty acids. www.nccam.nih.gov/health/tips/omega; accessed Feb. 10, 2014.