Hegarty BD, Parker GB. Marine omega‐3 fatty acids and mood disorders – linking the sea and the soul.

Objective:  While there has long been interest in any nutritional contribution to the onset and treatment of mood disorders, there has been increasing scientific evaluation of several candidate nutritional and dietary factors in recent years. In this inaugural study of our ‘Food for Thought’ series, we will overview the evidence for any role of omega‐3 fatty acids (FA) in regulating mood.

Method:  Relevant literature was identified through online database searches and cross‐referencing.

Results:  Plausible mechanisms exist by which omega‐3 FA may influence neuronal function and mood. Cross‐sectional studies demonstrate an association between omega‐3 fatty acid deficiency and both depressive and bipolar disorders. Studies investigating the efficacy of omega‐3 fatty acid supplementation for mood disorders have however provided inconsistent results. The proportion of treatment studies showing a significant advantage of omega‐3 supplementation has dropped over the last 5 years. However, the vast heterogeneity of the trials in terms of constituent omega‐3 FAs, dose and length of treatment makes comparisons of these studies difficult.

Conclusion:� More research is required before omega‐3 supplementation can be firmly recommended as an effective treatment for mood disorders. Whereas increased omega‐3 FA intake may alleviate depressive symptoms, there is little evidence of any benefit for mania.