Essential fatty acids, also known as polyunsaturated fats, serve a number of purposes in the body. The body doesn't manufacture essential fatty acids, so dietary intake is essential. One type of essential fatty acids, Omega-3 fatty acids, occurs naturally in a number of oily fish as well as in certain plants and vegetables. Recently, several studies have looked at the benefit of Omega-3 fatty acids for use in treating depression, which has increased in incidence 20-fold since 1945, Alan Logan of the Integrative Care Centre in Canada reported in the November 2004 issue of "Lipids in Health and Disease."
Docosahexaenoic Acid
Fish and fish oils contain two types of Omega-3 fatty acid, one of which is docosahexaenoic acid. Levels of docosahexaenoic acid, better known as DHA, have been lower in people with depression than people without depression in some small studies, the Linus Pauling Institute of Oregon State University reports. Logan reports that one study found 34.6 percent less DHA in serum and tissue in people with depression compared to people without depression. Logan also reported on another study that found that an increase in DHA of 1 percent in the blood reduced postpartum depressive symptoms by 59 percent. In these studies, DHA is added to antidepressant medications, not taken alone of treatment of depression, Psycheducation warns. Other studies on the effects of Omega-3 fatty acids such as DHA have had mixed or negative results. Most studies have used compounds containing both DHA and the other Omega-3 fatty acid found in fish, eicosapentaenoic acid, or EPA.
Eicosapentaenoic Acid
Studies on Omega-3 fatty acids often combine both DHA and eicosapentaenoic acid, or EPA. Psycheducation reports on several studies that found some benefit on treating depression with EPA alone or in conjunction with DHA, in addition to antidepressants. A 2008 study reported in the "New Zealand Journal of Psychiatry" reported by S Jazayeri of Tehran University of Medical Sciences found that 56 percent of people with depression taking EPA alone had an improvement in depression compared to 50 percent taking Prozac, an antidepressant alone. Taking both together was most effective, reducing depression by 81 percent.
Alpha-linolenic Acid
Alpha-linolenic acid, also known as ALA, the Omega-3 fatty acid found in plants and vegetables can be converted to DHA and EPA, but the process is not as efficient as obtaining the fatty acids directly from fish or fish oil. While ALA may be a viable substitution in the diet for Omega-3 fatty acids obtained from fish for vegetarians and others who can't eat fish, studies on the specific benefits of ALA rather than DHA or EPA for depression haven't been done.
References
- PsychEducation: Omega-3 Fatty Acids
- University of Maryland Medical Center: Omega-3 Fatty Acids
- "New Zealand Journal of Psychiatry": Comparison of Therapeutic Effects of Omega-3 Fatty Acid Eicosapentaenoic acid and Fluoxetine; JS Jazayeri; 2008
- "Lipids in Health and Disease": Omega-3 Fatty Acids and Major Depression: A Primer for the Mental Health Professional; Alan Logan, 2004
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