Decosahexaenoic acid, or DHA, is a type of omega-3 fatty acid. It is an essential fatty acid, meaning that your body cannot produce sufficient amounts for proper health. For this reason, you must obtain DHA from food sources or supplements. DHA serves several important functions in the human body.
Sources
DHA is found in coldwater fatty fish such and mackerel, herring, tuna, sardines, halibut and salmon. Fish oil supplements derived from these fish can also supply DHA in your diet. Your body can also manufacture DHA from alpha-linolenic acid, or ALA, which is found in vegetarian food sources such as flaxseed oil, walnuts, soybeans, pumpkin seeds and canola oil. However, the conversion of ALA to DHA is inefficient in the human body.
Functions
The cells of your retinas contain high concentrations of DHA. This fatty acid may be necessary for the development of the retinas. DHA may also aid in the production of rhodopsin, a pigment that aids in the conversion of light into visual images in your brain. Additionally, DHA may aid in proper nervous system function and prevent learning difficulties. This fatty acid may also affect the availability of neurotransmitter chemicals that affect brain function. However, research regarding the role of DHA in vision and brain function has largely been limited to animal studies, so the role of DHA in humans is not clear, according to the Linus Pauling Institute.
Dosage
No official recommended daily intake of DHA exists. However, doses of 1,000 to 2,500 mg per day have been used in studies, and fish oil supplements commonly contain 3,000 mg to 4,000 mg per capsule. Two to three servings of fatty fish, such as mackerel, salmon or tuna, per week provide approximately the equivalent of 1,250 mg of DHA per day.
Considerations
Although DHA is generally considered safe, even at supplemental doses of 3,000 to 4,000 mg per day, DHA may increase your risk of bleeding, particularly when taken in conjunction with prescription blood thinners. Also, DHA may reduce blood pressure. Talk to your doctor before adding DHA from food sources or dietary supplements if you take blood pressure medications.
References
- University of Maryland Medical Center; Decosahexaenoic Acid; Steven D. Ehrlich, N.M.D.; September 2008
- University of Maryland Medical Center; Omega-3 Fatty Acids; Steven D. Ehrlich, N.M.D.; June 2009
- University of Maryland Medical Center; Flaxseed Oil; May 2010
- Linus Pauling Institute at Oregon State University; Essential Fatty Acids; Jane Higdon, Ph.D.; December 2005
Member Comments