Omega-3 fatty acids, such as those found in flaxseed and fish oils, have garnered a lot of attention over the past decade for their purported health benefits. The Center for Genetics, Nutrition and Health reports that increased consumption of omega-3 fatty acids reduces your risk of cardiovascular disease, cancer and inflammatory and autoimmune diseases. A well-balanced diet containing plant foods and fish would supply adequate levels of omega-3s, but many Americans opt for supplements.
Flaxseed Oil Supplies ALA
Dr. Elson Haas, author of "Staying Healthy with Nutrition," contends that only two fatty acids -- linoleic and alpha-linolenic -- are essential for human health. These two essential fatty acids, or EFAs, can ostensibly be converted in your cells to all the other fatty acids your body requires. Linoleic acid is an omega-6 fatty acid found in many plant oils, while alpha-linolenic acid, or ALA, is the omega-3 fatty acid found in flax.
DHA and EPA from Fish Oil
A 2004 review in "Current Opinion in Clinical Nutrition and Metabolic Care" reveals that the conversion of ALA to two other important fatty acids is inefficient in humans. Eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA, are instrumental in many important functions in your tissues, and both are present in fish oil. Even though small amounts of EPA are produced from ALA conversion, the subsequent synthesis of DHA from EPA is quite low. Thus, ALA conversion is not considered adequate to meet your needs for EPA or DHA.
ALA, DHA and EPA All Needed for Optimal Health
The various metabolic activities of ALA, EPA and DHA are not necessarily interchangeable. For example, DHA serves important roles -- not duplicated by EPA or ALA -- in the development and support of healthy nerve tissue. ALA down-regulates the production of inflammatory chemicals called prostaglandins in your cells, and both DHA and EPA are metabolized to form several anti-inflammatory compounds called "resolvins" and "protectins."
Recommendations
Most of the data surrounding the supplementation of omega-3 fatty acids has emerged from research on the effects of these compounds on cardiovascular disease. A 1999 National Institutes of Health Workshop recommended that Americans consume 1 percent of their total calories in the form of ALA, while another 0.2 percent should be composed of an equal combination of EPA and DHA. Thus, a good mix of flax and fish oils would provide around 250 mg each of EPA and DHA while supplying 2.5 g of ALA every day.
References
- "Experimental Biology and Medicine"; The Importance of the Omega-6/Omega-3 Ratio in Cardiovascular Disease and other Chronic Diseases; A.P. Simopoulos; June 2008
- "Staying Healthy with Nutrition: Lipids"; Elson M. Haas, M.D.; 2006
- "Current Opinion in Clinical Nutrition and Metabolic Care"; Alpha-Linolenic Acid Metabolism in Men and Women: Nutritional and Biological Implications; G. Burdge; March 2004
- "European Heart Jounal"; Dietary Alpha-Linolenic Acid Diminishes Experimental Atherogenesis and Restricts T Cell-Driven Inflammation; S. Winnik, et al.; February 2011
- "The Journal of Clinical Investigation"; Pro-resolving Actions and Stereoselective Synthesis of 18S E-Series Resolvins in Human Leukocytes and Murine Inflammation; S.F. Oh, et al.; January 2011
- "Journal of the American College of Nutrition"; Workshop on the Essentiality of and Recommended Dietary Intakes for Omega-6 and Omega-3 Fatty Acids; A.P. Simopoulos; 1999
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