Sublette ME, Hibbeln JR, Galfalvy H, Oquendo MA, Mann JJ. (2006) Am J Psychiatry 163(6): 1100-2
OBJECTIVE: Low levels of docosahexaenoic acid, a polyunsaturated fatty acid, and elevated ratios of omega-6/omega-3 fatty acids are associated with major depression and, possibly, suicidal behavior. Predicting risk of future suicidal behaviors by essential fatty acid status merits examination.
METHOD: Plasma polyunsaturated fatty acid levels in phospholipids were measured in 33 medication-free depressed subjects monitored for suicide attempt over a 2-year period. Survival analysis examined the association of plasma polyunsaturated fatty acid status and pathological outcome.
RESULTS: Seven subjects attempted suicide on follow-up. A lower docosahexaenoic acid percentage of total plasma polyunsaturated fatty acids and a higher omega-6/omega-3 ratio predicted suicide attempt.
CONCLUSIONS: A low docosahexaenoic acid percentage and low omega-3 proportions of lipid profile predicted risk of suicidal behavior among depressed patients over the 2-year period. If confirmed, this finding would have implications for the neurobiology of suicide and reduction of suicide risk.
This study shows for the first time that in patients with clinical depression, that low blood omega-3 may help to predict future suicide risk. This is an important finding, and replication studies are clearly warranted.
Many studies have already shown that people with depression and other psychiatric disorders often have low blood levels of the long-chain omega-3 fatty acids found in fish oils (EPA and DHA). And a prospective case-control study from China found low blood omega-3 in hospitalised patients who had attempted suicide vs matched controls admitted for accidental injury - see Huan et al 2004.
Existing evidence also shows that dietary supplementation with these omega-3 can actually help to alleviate depressive symptoms. See Freeman et al 2006 for the American Psychiatric Association's review and treatment recommendations.
Findings from the current study suggest that fewer depressed patients might go on to commit suicide if more doctors were to follow these treatment recommendations.
Further research is obviously needed to confirm this, but an increased intake of omega-3 is already a safe and relatively simple option for improving general health as well as alleviating depressive symptoms.