Omega-3 fatty acids may be effective in treating depression

According to a new review from Italy, omega-3 fatty acid supplements can significantly reduce symptoms in patients with diagnosis of major depressive disorder.

The meta-analysis included 19 randomized controlled trials investigating potential effects of treating patients with depressive symptoms with supplements containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for an average of four months (1). The analysis showed that, compared to placebo, treatment with preparations containing mainly EPA (mean of 1.93 g), rather than DHA (0.86 g), significantly improved depressive symptoms in patients with a diagnosis of major depressive disorder (MDD) and patients with depressive symptomatology but no diagnosis of MDD. Significant clinical efficacy showed these preparations as adjuvant rather than in mono-therapy. While omega-3 fatty acid treatment reduced depressive symptoms of patients with bipolar disorder, no significant effects were found in young populations, perinatal depression, primary disease other than depression and healthy subjects.

The researchers commented that omega-3 fatty acids have been demonstrated to be effective in cardio- vascular disease (CVD) prevention due to their anti-inflammatory and cardio-protective effects (2). Recently, new therapeutic indications for omega-3 fatty acids have been proposed, such as treatment for certain forms of mental illness, including depressive disorders (3). Indeed, some psychiatric diseases as depression may share certain pathophysiological mechanisms with CVD, namely increased production of pro-inflammatory cytokines, endothelial dysfunction, and elevations in plasma homocysteine levels. The positive effects of omega-3 fatty acids on depression may depend on their physiological abundant content in the human ner- vous system and their involvement in nerve cell generation (neurogenesis) and adaptation (neuroplasticity) (4). Moreover, their anti-inflammatory capacity may counteract inflammatory processes occurring in depres- sion. According to the scientists, previous meta-analyses included clinical trials with little distinction among population groups, leading to controversial results, such as overall benefit and negligible effects of omega-3 fatty acids against depressive symptoms, especially due to the high heterogeneity of studies.

1. Grosso G. et al. Role of omega-3 Fatty acids in the treatment of depressive disorders: a comprehensive meta-analysis of randomized clinical trials. PLoS One. 2014; 9(5):e96905.
   
2. Kotwal S. et al. Omega 3 Fatty acids and cardiovascular outcomes: systematic review and meta-analysis. Circ Cardiovasc Qual Outcomes. 2012; 5:808–818.
   
3. Grosso G. et al. Omega-3 Fatty Acids and Depression: Scientific evidence and Biological Mechanisms. Oxid Med Cell Longev. 2014; 313570.
   
4. Bourre J. M. Roles of unsaturated fatty acids (especially omega-3 fatty acids) in the brain at various ages and during ageing. J Nutr Health Aging. 2004; 8:163–174.