Sufficient omega-3 fatty acid intakes may reduce the risk of depression

Higher intakes of omega-3 fatty acids seem to be associated with a significant reduction in the risk of developing depressive symptoms in women, reports new US research.

The observational study estimated omega-6 and omega-3 fatty acid intakes and measured self-reported symptoms of depression in 1,746 men and women, aged 30 to 65 years (1). The study results showed that while adequate intakes of the omega-6 fatty acid linoleic acid (LA) were observed in 43 to 59% of men and women, significantly fewer participants, between 5.2 and 17.2%, achieved adequate intakes of omega-3 fatty acids – eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The prevalence of elevated depres-sive symptoms was 18.1% among men and 25.6% among women. However, women with the highest intakes of omega-3 fatty acids had a significant 49% reduction in the risk of developing elevated depressive sym-ptoms.

The researchers commented that these findings supported the hypothesis of a protective effect of omega-3 fatty acids against depressive symptoms, particularly among women (2). They stated that although reverse causality could not be ruled out, it was more likely that reduced concentrations of omega-3 fatty acids con-tributed to symptoms of depression and not vice-versa. However, additional studies using supplemental omega-3 fatty acid intakes in combination with dietary intakes would be necessary to verify a cause-and-effect relationship. Speculating on potential biochemical mechanisms, the scientists said that omega-3 fatty acids may positively influence symptoms of depression by affecting the serotonergic neurotransmitter syst-em, promoting the formation of anti-inflammatory compounds (while omega-6 fatty acids are thought to promote pro-inflammatory eicosanoids), or influencing impaired phospholipid metabolism and fatty acid–related signal transduction.

1. Beydoun M. A. et al. Omega-3 Fatty Acid Intakes Are Inversely Related to Elevated Depressive Symptoms among United States Women. Journal of Nutrition. Published online September 2013.
2. Lin P. Y. et al. Are omega-3 fatty acids antidepressants or just mood-improving agents? The effect dep-ends upon diagnosis, supplement preparation, and severity of depression. Mol Psychiatry. 2012; 17:1161–1163.