Bipolar disorder is a common illness characterized by alternating, recurrent episodes of depression and mania. A growing body of scientific evidence has accumulated over the past 10 years suggesting an association between insufficient dietary intake of omega-3 fatty acids (such as those found in fish oil) and several psychiatric illnesses, particularly those involving mood disorders.
The few available scientific studies show results that, while difficult to interpret, seem to suggest that omega-3 fatty acids do improve depression symptoms in patients affected by bipolar disorder, and other depressive conditions (Lin & Su, Journal of Clinical Psychiatry, 2007). Effects on manic symptoms, on the other hand, do not appear from these studies. Research on the effects of omega-3 fatty acids and bipolar disorder continues, however, spurred by evidence of a connection provided by different types of scientific studies:
Physiological and biochemical evidence. The brain is one of the organs with the highest level of lipids (fats), and omega-3 fatty acids make up approximately one third of the lipids of the brain cortex (the gray matter). It is known that nutritional deficiencies of these nutrients affect brain function. For example, experiments measuring the neurological and intellectual performance of babies fed formula milk that varied in omega-3 fatty acid content revealed a significant connection (Bourre JM, Medical Science (Paris), 2005) .
Epidemiological evidence. The prevalence of bipolar, and other disorders in different countries is lower where fish oil intake, through fish consumption, is higher, an indirect measure of omega-3 fatty acid intake (Noaghiul and Hibbeln, American Journal of Psychiatry, 2003). In fact, the connection between mood problems and omega-3 fatty acids goes one step further, as blood levels of these nutrients can predict suicide risk in depressive patients (Sublette et al., American Journal of Psychiatry, 2006).
Pending further research, the use of fish oil for patients with bipolar disorder is currently endorsed by the medical community, as a complement to other forms of therapy (Turnbull et al, Archives of Psychiatric Nursing, 2007; Montgomery & Richardson, Cochrane Datab. Syst. Review, 2008). This recommendation is primarily based on two considerations: first, while not conclusive, there is substantial evidence of a beneficial effect on depression symptoms; second, there are next to no adverse side effects reported, and limited to occasional, mild, and transient gastrointestinal symptoms.
