Kathy McManus, M.S., R.D is the director of the department of nutrition at Brigham and Women's Hospital and an investigator on the Pounds Lost Trial, a 5 year NIH funded obesity study. She graduated with a Bachelor of Science from Simmons College, completed her Dietetic Internship at Brigham and Women Hospital, and received a Master of Science degree in nutrition from Framingham State College.

Question:

Is there any difference in the omega-3 found in fish oil and the omega-3 from flaxseed oil? Also, is DHA found in all omega-3 supplements, or is it something that is added?

Answer:

Yes, there is a difference between the omega 3 found in fish versus that found in flax oil. Fish oil is superior because it contains both docohexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which play crucial roles in the body. Flax oil, however, contains alpha-linolenic acid (ALA). The body converts ALA to EPA, and then EPA to DHA. This conversion is very inefficient, meaning it takes a lot of ALA to make EPA and DHA.

Omega 3 supplements typically contain both DHA and EPA but in varying amounts. Look for a supplement with a combined dose of 500 to 1,000 milligrams of DHA plus EPA a day.

Foods rich in DHA/EPA include fatty fish like salmon, light tuna, sardines and herring. Omega fortified eggs also include some DHA/EPA. Besides flaxseed, foods rich in ALA include walnuts, canola oil and soy foods.