Consuming fish oil may help improve symptoms of depression, though more study is needed to determine just how effective supplementing with it really is, according to MedlinePlus. The omega-3 fatty acids in fish oil are "brain food" that can help alleviate conditions like bipolar disorder, attention deficit hyperactivity disorder and thinking disorders. The fatty acids might work, in part, by improving your serotonin levels.
Effect
Serotonin is a neurotransmitter in your brain that is involved in many functions including mood, appetite control, temperature regulation, sleep, behavior, memory and learning. Neurotransmission is not as effective if your receptors are not fully receptive. Fish oil enhances the fatty membranes in your neurons by keeping them soft and flexible. Animal fats, in contrast, negatively affect receptors by making them more rigid, according to "The Brainpower Plan," by Jordan K. Davis, et al. Omega-3s alter membrane fluidity by displacing cholesterol from the membranes, notes a November 2004 "Lipids in Health and Disease" study.
Theory
High levels of docosahexaenoic acid, or DHA, one of the omega-3 fatty acids in fish oil, are associated with high serotonin levels in your brain, according to Davis. Theoretically, Davis notes, this is because your body uses fish oil to create more connections, including synapses. This, in turn, leads to higher serotonin levels. Serotonin is activated when your neurons release it into your synapses.
More Research Needed
Low concentrations of DHA are associated with low concentrations of cerebrospinal fluid 5-hydroxyindoleacetic acid, or CSF 5-HIAA, which is a marker of brain serotonin turnover, according to an April 1998 study in "The Lancet." Low concentrations of CSF 5-HIAA are associated with suicide and depression, study author Joseph R. Hibbeln notes. Despite this correlation, fish oil consumption does not statistically make a difference in the prevalence of major depression, and consuming fish or fish oil does not appear useful in treating depression, the study concludes.
The "Lipids in Health and Disease" study also notes an apparent correlation between higher fish oil consumption and decreased risk for depression. This study, however, flags the other omega-3 fatty acid, eicosapentaenoic acid, or EPA, as a potential agent for treating depression due to its anti-inflammatory action. More research on DHA and EPA and their effect on depression are needed before researchers can draw firm conclusions on whether these fatty acids are effective for treating this condition, according to lead study author Alan C Logan.
Appetite
Long-term consumption of fish oil may affect your appetite, according to a June 2010 study published in "Cellular and Molecular Neurobiology." Consuming fish oil over time affects hypothalamic serotonin turnover by lowering it. This stops serotonin-induced hypophagia, which is reduced food intake, notes lead study author R.L. Watanabe. This study was done on rats, however, so more research is needed to see if humans are affected the same way.
References
- MedlinePlus: Fish Oil
- "The Brainpower Plan"; Jordan K. Davis, et al.; 2009
- "Lipids in Health and Disease"; Omega-3 Fatty Acids and Major Depression: a Primer for the Mental Health Professional; Alan C. Logan; November 2004
- "The Lancet"; Fish Oil Consumption and Major Depression; Joseph R. Hibbeln; April 1998
- "Cellular and Molecular Neruobiology"; Long-term Consumption of Fish Oil-Enriched Diet Impairs Serotonin Hypophagia in Rats; R.L. Watanabe, et al.; October 2010
- Bryn Mawr College: Serotonin and Its Uses; Andrea Byrd; 1999
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