Docosahexaenoic acid, or DHA, has been suggested as a treatment for depression. DHA is an omega-3 fatty acid needed for cognitive function. It is found in fish oil supplements and cold-water fatty fish, along with eicosapentaenoic acid, or EPA, another omega-3 fatty acid. It's also found in seaweed.
Omega-3 Fatty Acids
Omega-3 fatty acids have been investigated for their role in depression, although studies have shown conflicting results. Dietary intake of omega-3 fatty acids does not appear to be associated with low mood level, according to a 2004 study published by Reeta Hakkarainen and colleagues in the "American Journal of Psychiatry." In a 2003 study published Kuan-Pin Su and colleagues in "European Neuropsychopharmacology," omega-3 fatty acid supplementation was found to have potentially beneficial effects. A meta-analysis of studies found that DHA without EPA may not be sufficient to treat major depression, but EPA on its own may sometimes give a benefit. The 2007 study was published by Parris M. Kidd in "Alternative Medicine Review."
Effects
DHA was tested as a treatment for depression and found to be ineffective in a 2003 study published by Lauren B. Marangell and colleagues in the "American Journal of Psychiatry." It was also found to be ineffective for postpartum depression, according to a 2003 study published by Antolin M. Llorente and colleagues in the "American Journal of Obstetrics & Gynecology."
Considerations
In the 2003 Marangell study, participants were given 2g of DHA a day or placebo for six weeks, and no significant difference was found. The researchers pointed out that it was possible that 2g of DHA was not enough to produce beneficial results, or that six weeks was not long enough. They also noted that in other studies that showed omega-3 fatty acids may reduce depression symptoms, participants were deficient in omega-3s. In this study, participants were not deficient at baseline.
Bipolar
The researchers in the 2003 Marangell study also noted that the study did not test for DHA's effect on bipolar disorder. People with bipolar disorder also experience depression. The greater the seafood consumption per capita in a country, the lower the prevalence of bipolar spectrum disorders, according to the 2007 Kidd study. Omega-3 fatty acids may help reduce symptoms of depression in people with bipolar disorder, found a 2008 review published by Paul Montgomery and Alexandra J. Richardson in the Cochrane Database of Systematic Reviews. The study did not analyze the effects of DHA alone.
EPA
Both EPA combined with DHA and EPA on its own have been found to help treat bipolar disorder, according to the 2007 Kidd study. EPA may be the most effective of the two omega-3 fatty acids. It has been found to treat bipolar depression on its own, according to a 2006 study published by Sophia Frangou in "The British Journal of Psychiatry."
References
- American Journal of Psychiatry: A Double-Blind, Placebo-Controlled Study of the Omega-3 Fatty Acid Docosahexaenoic Acid in the Treatment of Major Depression
- American Journal of Obstetrics & Gynecology: Effect of Maternal Docosahexaenoic Acid Supplementation on Postpartum Depression and Information Processing
- American Journal of Psychiatry: Is Low Dietary Intake of Omega-3 Fatty Acids Associated With Depression?
- "European Neuropsychopharmacology;" Omega-3 Fatty Acids in Major Depressive Disorder A Preliminary Double-blind, Placebo-controlled Trial; Kuan-Pin Su, et al.; 2003.
- Cochrane Database of Systematic Reviews: Omega-3 Fatty Acids for Bipolar Disorder
