Nutrition and depression: A review of the evidence

Abstract

Background: There is increasing speculation that diet has an important impact on mental health and that the outcomes of certain mental health disorders, including depression may be influenced by nutritional factors. Although considerable research has focused on understanding the biochemistry and assessing the efficacy of pharmaceutical interventions for depression, it is only recently that research attention has focused on the impact of diet. Emerging evidence suggests that certain nutrients may be important in the pathogenesis and treatment of depression.

Aims: This review seeks to establish the current evidence base supporting nutritional interventions in unipolar depression.

Methods: Literature searches identified articles relating to nutritional supplementation in unipolar depression. These were subdivided into categories. All randomized controlled trials were graded using SIGN 50 criteria, with an overall grading recommendation assigned to the evidence for each nutrient.

Results: Ten randomized controlled trials were graded, comprising two tryptophan studies, four omega 3 studies and one zinc study. All categories except the single zinc trial achieved a combined B grading level.

Conclusion: At present the evidence base is extremely weak but hints at a potential benefit of adjunctive nutritional supplementation in the treatment of depression and highlights the urgent need for more research in this area.

Declaration of interest: This review was carried out independently, with no financial support obtained from any party. The authors declare no interests.

Keywords:

• Depression
• supplementation
• carbohydrate
• tryptophan
• omega-3
• folate
• zincB12
• zinc