Docosahexaenoic acid, called DHA, and andeicosapentaenoic acid, called EPA, are the primary fatty acids in naturally occurring omega-3. These essential nutrients play a central role in childhood brain development and adult brain functioning. A 2007 review article by Parris M. Kidd, PhD, in "Alternative Medicine Review" reports that these two acids might underlay the health benefits of omega-3 -- including relief from depression.
Neuronal Membranes
DHA and EPA might be related to depression because of basic neurochemistry. The primary function of brain cells is to transmit neurotransmitters such as serotonin. When brain cells fail to transmit these chemicals effectively, the result can be a myriad of psychiatric problems, including depression. According to the " DHA/EPA Omega-3 Institute," DHA is an important component of neuronal membranes. These membranes form the outer layer of brain cells and help maintain their integrity. A low intake of DHA may cause these membranes to function poorly and cause depression.
Brain Plasticity
The brain relies upon both DHA and EPA throughout life to create and alter neural structures -- making the brain an ever-changing organ. This changing and adaptive nature of the brain is referred to as "plasticity". According the Kidd, brain plasticity requires both DHA and EPA. A lack of these acids reduces the adaptability of the brain. It is thought that reduced plasticity may be at least one important factor in the development of depression.
Significant Change
If either brain plasticity or neuronal membranes are directly related to depression, increasing these fatty acids should decrease depression in patients. Kidd reports research demonstrating that volunteers taking 800 mg of DHA and 1,600 mg of EPA experienced a significant decrease in depression. The review reports data from studies which, for over a decade, support these results. Results also suggest that DHA taken without EPA might not be as effective at reducing depression as the two combined. This research also suggests a link between postpartum depression and DHA/EPA deficiencies that might have developed during pregnancy.
Inconclusive Results
Not all researchers agree, however, on the evidence suggesting a link between DHA/EPA and depression. In the January 2008 issue of "Journal of Psychiatry and Neuroscience," Dr. Simon Young says that different studies have looked at the separate and combined effects of EPA and DHA with various amounts -- from 1 g to almost 10 g per day. In general, Young says, the results are inconsistent. Research into the effects of DHA and EPA may one day prove these fatty acids to be important resources for treating depression, but research remains inconclusive.
References
- "Alternative Medicine Review"; Omega-3 DHA and EPA for Cognition, Behavior, and Mood: Clinical Findings and Structural Functional Synergies with Cell Membrane Phospholipids ; Parris M. Kidd, PhD; 2007.
- "Journal of Psychiatry and Neuroscience"; Fish Oil for Depression?; Simon N. Young; January 2008
- " DHA/EPA Omega-3 Institute"; Review : DHA/EPA Blood Levels Lower in Patients with Depression"
