Diets and risk of depression

Depression is a mental health issue that impacts over 300 million people worldwide (with a global prevalence of 7% for women and 4% for men). It’s a major contributor to the burden of diseases and a leading cause of global disability, costing the world economy $1 trillion in lost productivity annually. 

Given this, there’s an urgent need to gather evidence on how nutrition plays a role in depression to shape recommendations and guide future mental health care. A recent review and analysis of observational studies explored the connection between diet quality and depressive outcomes to evaluate the effectiveness of dietary interventions in preventing depression. 

The study examined 41 research papers (20 longitudinal and 21 cross-sectional), delving into various nutritional aspects like adherence to the Mediterranean Diet, Healthy Eating Index, Alternative Healthy Eating Index, Dietary Approach to Stop Hypertension, Dietary Inflammatory Index, and other scores related to national dietary guidelines or general “diet quality.” 

Consistent findings indicate that higher adherence to a Mediterranean diet and lower adherence to a pro-inflammatory diet are robustly associated with a lower risk of depression, based on analyses of longitudinal studies. However, there is less conclusive evidence for indices like the Healthy Eating Index and certain country-specific dietary guidelines. 

Unfortunately, results are inconclusive for the Dietary Approach to Stop Hypertension, and findings related to Dietary Inflammation Index and Healthy Eating Index show significant variability in outcomes and data collection related to dietary habits, posing a limitation. Another limitation is the applicability of the findings to low- and middle-income countries. 

In summary, this systematic review supports the idea that following a healthy diet, especially a typical Mediterranean one, and avoiding a pro-inflammatory diet may lead to a lower incidence of depressive symptoms or clinical depression.
Consuming more fruits, vegetables, and nuts, along with reduced intake of pro-inflammatory foods like processed meats and trans fats, and moderate alcohol consumption, has been associated with better metabolic health outcomes linked to depression.  

This research is the first to provide a comprehensive overview of various food quality indices and their connection to depression outcomes. To thoroughly assess the impact of dietary patterns on preventing, managing, and reducing the recurrence of depressive episodes, more well-designed clinical trials are necessary.