Association between serum levels of essential elements (copper, zinc, and iron) and major depressive disorder: a systematic review and meta-analysis

This study demonstrates consistent reductions in serum zinc and iron among individuals with MDD, supporting their potential role in depressive pathophysiology. While copper findings were inconclusive, the stability of zinc and iron results highlights the clinical relevance of micronutrient assessment in depression. These findings provide a foundation for future research in nutritional psychiatry and adjunctive treatment strategies.