Abstract
This paper reviewed the evidence for the efficacy of omega‐3 fatty acids against depression and depressive symptoms, focusing on anti‐inflammatory effect. Inflammation is one of the potential pathogenesis of depression. Omega‐3 fatty acids, especially eicosapentaenoic acid (EPA) , have anti‐inflammatory effect. A number of meta‐analyses of randomized controlled trials (RCTs) support the positive effects of EPA supplementation in treating depression and reducing depressive symptoms. Thus, anti‐inflammatory effect is believed to be one of the mechanisms for anti‐depressant action of EPA. However, the amount of omega‐3 fatty acids and intervention duration varied across previous RCTs. Moreover, there is no clear evidence on the optimal amount of supplemental omega‐3 fatty acids for different countries with different levels of fish consumption and there are especially few available evidences in countries, such as in Japan, where people consume much more fish than in other countries..
Nutritional approaches for depressive symptoms could be widely applicable to various populations including pregnant women and children due to potentially fewer side effects as compared with pharmaceutical approaches. Further studies should explore the possibilities in practical use of nutritional approaches in prevention and treatment of depression.
