Omega-3 fatty acids may improve depressive symptoms

Patients treated with antidepressants may show greater improvement in symptoms of depression when they take daily omega-3 fatty acids supplements, says a new study from the Netherlands.

In the randomized controlled trial, 4,116 patients (aged 60-80 years) who had experienced a myocardial infarction were assigned to consume margarine spreads that either provided a daily dose of 2 grams of
plant-derived alpha-linolenic acid (ALA) , 400 milligrams fish-derived eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), ALA plus EPA/DHA, or a placebo every day for 40 months (1). To evaluate a potential link between omega-3 fatty acid intakes and mood, symptoms of depression were measured by a questionnaire. The study results showed that the low-dose supplementation with omega-3 fatty acids did not significantly improve depressive symptoms when compared to the placebo group. However, a small group of patients who were prescribed antidepressant medications at baseline showed a greater improvement in depressive symptoms when taking EPA plus DHA.

Experts commented that it would be no surprise that low doses of omega-3 fatty acid supplements showed no effect in patients, most of whom had no psychiatric diagnosis and no depressed mood. Only people who actually suffer from depression would benefit from the supplements. In many studies, higher doses of long-chain omega-3 fatty acids (e.g., 1.2 grams per day) would have been shown to ameliorate depressive symptoms in depressed individuals (2).

1. Giltay E. J. et al. Effects of n23 fatty acids on depressive symptoms and dispositional optimism after myocardial infarction. American Journal of Clinical Nutrition. Published online October 2011.
2. Lespérance F. et al. The efficacy of omega-3 supplementation for major depression: a randomized controlled trial. Journal of Clinical Psychiatry. 2011; 72(8):1054–1062.