Getting your omega-3s

Thank you for drawing attention to omega-3s in your article, “10 nutrients that can lift your spirits” [Jan. 14]. While all types of omega-3s, plant-based and marine-based, are healthful, they are not the same and are not linked to the same health benefits. The most powerful omega-3s are called EPA and DHA and are found almost exclusively in marine foods (seafood and seaweed). DHA is the big player in brain development and health. The type of omega-3s found in plant foods are called ALA and the body is quite inefficient at turning ALA into EPA and DHA. Vegetarians or people who don’t eat fish can take an algae-based supplement to get their EPA and DHA. This is particularly important for pregnant women looking to reap the brain-boosting benefits of DHA for themselves and their babies.

Additional information is available in this 2012 Q&A from Tufts nutrition experts:

As a vegetarian, can I get enough omega-3 from walnuts, flax seed, canola oil and trace amounts in other foods?

The omega-3 fatty acids found in plant foods (ALA) have their own health benefits, but they are not the same as the omega-3s found in fish (DHA and EPA) that have been associated with heart-health benefits. According to Alice H. Lichtenstein, director of Tufts’ Human Nutrition Research Center on Aging Cardiovascular Nutrition Laboratory, while your body does convert ALA into DHA/EPA, studies have found that this conversion is very inefficient. Only between 3 percent and 5 percent of the ALA gets converted into EPA and as little as 0.5 percent to 9 percent into DHA. If you’re concerned about getting enough of the ­omega-3s found in fish, it is possible to buy vegetarian supplements that derive DHA from algae.

Jennifer McGuire, MS, RD, National Fisheries Institute, McLean, Va.