Improving diet for psychiatric patients : High potential benefits and evidence for safety

Background: Psychonutrition, i.e. the impact of diet on mental health, is an emerging field of psychiatry.

Objective: The purpose of the present letter was to highlight recent findings in the field to guide nutritional interventions in psychiatry.

Method: An overview of the most recent meta-analyses in the field of psychonutrition in severe mental disorders has been carried out.

Results: The Mediterranean diet showed the best evidence for effectiveness in diminishing the incidence of depressive symptomatology Complementary agents were found to be associated with lower depression levels (even in psychiatric populations): omegas 3 fatty acids, vitamin D, methylfolate and S-adenosylmethionine, all being found in high rates in the Mediterranean diet. The Healthy Eating Index (HEI) has also been found to be associated with lower depression. Moreover, major depression has been associated with inflammatory disturbances and a diet with a low Dietary Inflammatory Index has also been shown to be associated with lower depression. These effects may be mediated by microbiota modifications and probiotic supplementation has been recently shown to be effective in the treatment of depression. A high protein diet may also be particularly useful in psychiatry. The high protein diet has shown effectiveness in weight loss and increasing satiety with no evidence for deleterious effects in subjects without chronic conditions like renal failure, diabetes or cardiovascular disease. A reduction of 20% of calorific intake +/- intermittent fasting (i.e. fasting for 12 to 16 h per day) may also improve microbiota and therefore psychiatric conditions.

Conclusion: In light of these findings, diet modifications appear to be an underutilized tool with which to improve the mental and physical health of psychiatric patients.