Omega-3 fatty acids for vegetarians.

Two omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are found mainly in oily fish. These fats have been linked to a reduced risk of heart disease and stroke. Vegetarian diets contain low levels of EPA and DHA, mainly from dairy products and eggs; regan diets do not normally contain EPA or DHA. Our bodies can make small amounts of EPA and DHA from another fat, alpha-linolenic acid that is found in flax seeds and flax seed oil and, to a lesser extent, in canola oil and soy products. This production is very limited, however. A recent study examined the levels of EPA and DHA in the blood of British vegetarian, vegan, and non-vegetarian men. (1) Approximately 200 men were in each group. EPA and DHA levels were lower in the vegetarians than in the meat-eaters and were lower in the vegans than in the vegetarians. Is this cause for concern? Possibly. Low blood levels of DHA and EPA have been associated with heart disease, stroke, and Alzheimer's disease. Conversely, vegetarians have a lower risk of heart disease than meat-eaters.

Vegetarians can obtain DHA from microalgae. A German study gave 104 vegetarians a supplement containing either DHA-rich oil from microalgae or olive oil for 8 weeks. (2) At the beginning of the study, none of the subjects had what is considered to be a desirable level of DHA + EPA in their blood. Low levels were seen even in subjects who met or exceeded the recommendations for alpha-linolenic acid, which is used to make DHA and EPA. After using supplements, 69 percent of the group receiving the DHA had a desirable level of DHA + EPA. DHA supplements derived from microalgae can help vegetarians achieve desirable levels of DHA + EPA.

(1) Rosell MS, Lloyd-Wright Zechariah, Appleby PN, et al. 2005. Long-chain n-3 polyunsaturated fatty acids in plasma in British meat-eating, vegetarian, and vegan men. Am J Clin Nutr 82:327-34.

(2) Geppert J, Kraft V, Demmelmair H, Koletzko B. 2005. Docosahexaenoic acid supplementation in vegetarians effectively increases omega-3 index: a randomized trial. Lipids 40:807-14.