A Mediterranean-style Dietary Intervention Improves Mental Health in People with Depression: A Randomized Controlled Trial

The year in Nutritional Psychiatry started with the publication of the first RCT into the positive effect of a healthy diet on depression (the SMILES Trial). A new study bookended the year with similar promising results. 

In this study people with self-reported depression were randomly assigned to one of two groups. The first group received nutritional education, a fortnightly food box containing ingredients that adhered to the Mediterranean diet for three months, and six months of fish oil supplements. The control group were assigned to receive regular social support for the same amount of time. 

At the end of the trial the MedDiet group saw a significant reduction in their depression scores and overall Quality of Life with 60% fewer persons experiencing extremely severe levels of depression, 72% of anxiety and 69% of stress in the MedDiet group compared to the social support group. 

This was a small trial and replications of the SMILES are already underway which will give use a deeper understanding of the role of diet on mental health and clarify the most effective interventions for different treatment groups. 



Parletta, N., Zarnowiecki, D., Cho, J., Wilson, A., Bogomolova, S., Villani, A. Itsiopoulos, C., Niyongsenga, T., Blunden, S., Meyer, B., Segal, L., Baune, B. T. & O’Dea, K. (2017). A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: A randomized controlled trial (HELFIMED).Nutritional Neuroscience, 1-14. https://doi.org/10.1080/1028415X.2017.1411320