by Chas Gant MD, PhD
In a recent study (August 2011) published online in the Journal of Clinical Psychiatry, it was found that low levels of docosahexaenoic acid (DHA), the major omega-3 fatty acid concentrated in the brain, may increase suicide risk. A retrospective case-control study of 1600 United States military personnel, including 800 who had committed suicide and 800 healthy counterparts, showed that all participants had low omega-3 levels. However, the suicide risk was 62% greatest in those with the lowest levels of DHA.
According to Joseph R. Hibbeln, MD, acting chief, Section on Nutritional Neurosciences at the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, "Omega-3 is already recommended by the American Psychiatric Association as adjunctive therapy for anybody with a psychiatric disorder, especially for those with major depression."
Suicide rates in military personnel have doubled since the start of Operation Enduring Freedom and Operation Iraqi Freedom, and now "rival the battlefield in toll." Other data and research suggests that nutritional deficiencies in the omega-3 fatty acids may increase vulnerability to combat deployment stress, manifesting as psychiatric symptoms including adjustment disorders, PTSD, substance abuse and alcoholism, major depression, impulsive violence, and suicide. In addition, studies conducted in civilian populations have also suggested that low DHA levels are linked to increased risk for suicide attempts and may contribute to adverse psychiatric symptoms.
I suppose that the immediate response to this horrific data would be to somehow ensure that all military personnel receive 2 or 3 concentrated fish oil capsules a day, which would likely assure adequate delivery of DHA and offset the incidence of depression and suicide in most individuals. Such a widely applied treatment would be consistent with the current paradigm of medical care, e.g. - prevent or treat symptoms or conditions by blindly prescribing an intervention without first attempting to diagnostically determine who is the most vulnerable to certain conditions, based on their nutritional status, heredity or environmental stressors.
Simple, inexpensive, laboratory testing can measure DHA, its precursor fatty acids and also critically important, mood-elevating, omega 6 fatty acids, in order to determine who is nutritionally the most vulnerable to suicide and depression. Several B vitamins (B3, B5, B6, biotin), a few minerals (zinc, magnesium), vitamin C and carnitine (a nutrient involved with fatty acid metabolism), are all needed as cofactors to assist 4 enzymes in the synthesis of DHA. These simple laboratory tests could determine who would have the greatest difficulty in synthesizing DHA, and thus possesses the most vulnerability to depression and suicide.
Laboratory testing may also needed after treatments with appropriate fatty acids, minerals, B vitamins and other nutrients, because DHA and other omega-3 fatty acids can adversely compete for the enzymes required to synthesize mood-enhancing, omega-6 fatty acids, and could eventually worsen the symptoms of depression. Treatment with equal amounts of omega-3 fatty acids (e.g., fish oil) and omega-6 fatty acids (e.g., borage oil) could prevent this problem, but testing is still needed to determine who carries long-term risks for such imbalances.
One of the four enzymes required for DHA synthesis, Δ6-desaturase, does not work quite as well in almost ½ of the population because of a quirky alteration of the gene (called a polymorphism). Polymorphisms in this gene and one of the other 4 needed to synthesize DHA, Δ5-desaturase, has been shown to contribute to perinatal (pregnancy-related) depression. In order to determine who is genetically most vulnerable to DHA deficiency, and therefore suicide and depression, genomic testing could be critical.
Another way to determine who is likely to have genetic vulnerabilities to depression, addiction and other psychiatric disorders, is to take a simple family history. The more blood relatives one has with these disorders, the more likely it is that such common, modifiable genes exist. At the very least, such individuals should be given the opportunity to determine precisely their genetic risk through panels of genomic testing designed for this purpose, and then be provided with lifestyle and dietary counseling about managing their risk.
Across the board treatment of our armed services personnel with essential fatty acids may be needed immediately to offset depression, suicide, addiction and other psychiatric disorders, common in individuals exposed to high-stress, combat environments. Across the board treatment of everyone with essential fatty acids is probably also needed to immediately to offset their risks of depression, suicide, addiction and other psychiatric disorders, the most common disability in younger and middle aged adults.
Using laboratory testing to selectively determine who possesses the greatest nutritional, dietary and genetic risk of DHA deficiency, and thus depression, suicide, addiction and psychiatric disorders, especially in our armed services personnel who have sacrifice so much for us all, is an idea whose time has come.
 Baylin A et. al. (2007) α-Linolenic acid, Δ6-desaturase gene polymorphism, and the risk of nonfatal myocardial infarction. AJCN, Vol. 85, No. 2, 554-560.
 Xie L, Innis S (2009) Association of Fatty Acid Desaturase Gene Polymorphisms with Blood Lipid Essential Fatty Acids and Perinatal Depression among Canadian Women: A Pilot Study. J Nutrigenet Nutrigenomics. Vol. 2, 243-250