Dietary Patterns as Modifiable Risk Factors for Depression: a Narrative Review

Background: The role of nutrition in treating clinical depression has been widely discussed. Unhealthy lifestyle patterns, like lack of physical activity, junk food consumption, and irregular sleep patterns are common in depressed patients. Considering the mental and physical side-effects, the daily nutrition of these patients seems to be a plausible option for reducing depressive symptoms and enhancing treatment results.

Methods: A PubMed search was done for meta-analyses published from January 2018 to June 2023 with the query: (diet) AND (psychiatric disorder) AND (depression). We selected meta-analyses that met specific criteria like including the entire diet or specific diet patterns and having depression or depressive symptoms as a primary or secondary outcome.

Results: Out of 28 papers found, the 9 meta-analyses, selected for review, revealed different types of correlation between dietary patterns and the symptoms of depression and anxiety. Healthy diets were associated with higher intake of fruits, vegetables, nuts, and lower intake of pro-inflammatory food items like processed meats and trans fats. Adherence to such diets showed a negative association with incident depression in cross-sectional and longitudinal studies. A diet mostly including ultra-processed foods was associated with higher odds of depressive and anxiety symptoms. Women were found to be more susceptible than men both in developing the depressive symptoms with unhealthy diet and in reducing the symptoms of depression and anxiety with improvement of diet quality. Statistically significant improvement in symptoms of depression and anxiety in both sexes was observed in study groups assigned for individual consultations of a dietician and a psychotherapist when compared with group sessions or general recommendations.

Conclusions: Research on the correlation of healthy dietary patterns and symptoms of depression and anxiety has mainly focused on non-clinical populations. The evidence supports an inverse association between healthy eating habits and symptoms of depression. Further research should be encouraged on the eating habits of clinically depressed individuals and the underlying physiological mechanisms of uncontrolled food intake.