Nutrition hotline: this issue's Nutrition Hotline addresses whether it is possible for omega-3 fatty acids to be vegan, as well as how and why you should aim to include them in your diet.

QUESTION: "I saw in a newspaper article that the Kellogg's Company might begin adding an omega-3 acid typically found in fish, to some of its products. The article said the fatty acid is vegetarian. Is that possible? How will I know if it is added to a food? Why would a company want to add this fatty acid to their products? Are there other ways to get it?" JC, via e-mail

ANSWER: The omega-3 fatty acid that Kellogg may begin adding to its products is DHA (docosa-hexaenoic acid), an omega-3 fatty acid that is usually found in fatty fish. Fish eat microalgae that contain DHA and then become a DHA source. Martek Biosciences Corporation has skipped the fish and developed a vegetarian DHA directly derived from microalgae. They recently signed an agreement with Kellogg's to begin developing products containing this DHA. At this point, we don't know which foods will contain DHA, although cereals are certainly a possibility.

Beth Parker, Manager of Public Relations at Martek Biosciences Corporation, told me that animal products are not used in the processing of Martek DHX[TM] and that the oil is derived from microalgae, not from animals. To the best of her knowledge, it is vegan. Crypthecodinium cohnii and Schizochytrium, two strains of algae that are naturally high producers of DHA, are used in the commercial production of Martek's DHA.

Martek only makes vegetarian DHA. Any products that contain Martek DHA[TM] must display the Martek DHA[TM] logo on the pack age and in product advertisements. Although the Martek logo does not guarantee that the product is vegetarian, it does indicate that it contains vegetarian DHA.

For example, Martek also sells DHA oil for use in nutritional supplements. Many companies package the oil in capsules containing animal-derived gelatin, but one company, NuTru[TM], produces O-MegaZen3, a completely vegetarian DHA supplement using Martek DHA[TM]. One advantage of microalgae-derived DHA is that it does not have the fishy smell or taste that is experienced with fish oil supplements.

There are several reasons why a company would add DHA to its products. The main one is consumer demand. DHA has been in the news a lot lately, In humans, high levels of DHA are found in the brain and in the retina (a part of the eye). Infants appear to need DHA to insure appropriate brain and retinal development. Pregnant women are encouraged to have dietary sources of DHA, and it is added to some infant formulas. Omega-3 fatty acids (DHA and others) reduce the risk of heart disease, stroke, and high blood pressure. The American Heart Association and the latest Dietary Guidelines both recommend increasing intake of DHA and other omega-3 fatty acids.

The main dietary source of DHA is fish and fish oil. Our bodies are able to produce some DHA from alpha-linolenic acid, another omega-3 fatty acid, but we are not very efficient at this production. To maximize DHA production, vegetarians are encouraged to include good sources of alpha-linolenic acid, such as flaxseed, flaxseed oil, canola oil, tofu, soybeans, soybean oil, and walnuts, in their diets.

The use of DHA supplements by vegetarians is controversial. There is little evidence that adding DHA from fish or fish oil to an already healthful vegetarian diet has additional health benefits in terms of heart disease or high blood pressure. On the other hand, some people will opt to use DHA supplements or fortified foods containing microalgae-derived DHA as a simple way of insuring adequate intake. (For more about DHA and heart health, see Vegetarian Journal, Issue 1, 2005.) Breastfeeding women who have little or no dietary DHA (from fish) may choose to use DHA supplements to make sure that their infants get enough DHA in breastmilk.

One concern about widespread fortification with DHA is that excess intakes appear to interfere with immune system function and may cause bleeding and easy bruising. Researchers are not certain what the highest 'safe' level of DHA is, so consumers should not go overboard when using products containing DHA.