Not All Omega-3 Fatty Acids Are Created Equal
Before you load your shopping cart with fortified products, it helps to know that your body uses some omega-3 fatty acids more efficiently than others.
There are three types of omega-3 fatty acids. DHA and EPA are the two with the most proven benefits, and they're found mostly in seafood and marine algae. ALA is more difficult for the body to use, and it's found in plant-based foods such as canola oil, flaxseed oil, soybean oil, and walnuts.
Read fortified-food labels closely. Scan the ingredients list next to the nutrition facts section and you'll discover that most functional foods are fortified with ALA omega-3 fatty acids from food sources such as flaxseed and canola oil.
The reason? ALA from plants doesn't impart strong odor or flavor to cereals, pasta, and other functional foods. DHA and EPA from fish sometimes do.
Omega-3 Fatty Acids: A Primer
Here, in brief, is research on the benefits of each omega-3 fatty acid:
- ALA (alpha-linolenic acid). ALA is found mostly in plants, such as spinach, kale, and other salad greens, as well as in flax, soy, walnuts, and canola oils. ALA is converted inside the body to EPA and DHA omega-3s. The catch is that this conversion isn't very efficient, says Christine Gerbstadt, MD, RD, a diabetes educator and spokeswoman for the American Dietetic Association. Some estimate that only about 5% of ALA gets changed into the more bio-available EPA and DHA.
- DHA (docosahexaenoic acid). DHA is a long-chain omega-3 fatty acid found mostly in seafood like salmon, tuna, and shellfish, though some can also be found in algae -- the same food some fish eat. Essential to the healthy brains of adults, DHA is also vital to the development of a child's nervous system and vision. Read the labels of functional foods like pastas, yogurt, and soy milk and you'll find many get their DHA boost -- between 16 and 400 milligrams -- from algae oils.
- EPA (eicosapentaenoic acid). EPA is found mostly in cold-water fish and fish oils. Like DHA, EPA is studied for its uses in aiding bipolar depression, lowering cancer risks, and reducing the risks of macular degeneration. Of the three fatty acids, EPA and DHA are the ones the body finds most easy to use. Experts suggest we get the bulk of our omega-3 fatty acids from DHA and EPA sources, such as fish, supplements, and some functional foods like margarine.
Studies suggest that ALAs can confer health benefits, and experts recommend getting at least 2 grams daily. But most of the research establishes the health benefits of DHAs and EPAs, which is why many dietitians encourage people to focus on getting these omega-3s in their diet.
That includes pregnant women, says Gerbstadt. She says research suggests that when pregnant women get at least 200 milligrams of DHA a day, their babies excel in cognitive development. And the effects seem to linger long after supplementation ends, Gerbstadt tells WebMD. But, to avoid issues concerning mercury-tainted fish, some experts suggest pregnant women get their omega-3s from algae-based supplements. Others recommend limiting the amount of fish per week to two servings per week and completely avoiding fish high in mercury.