Serum Ghrelin and Leptin Concentrations in Patients with Major Depressive Disorder before and after Supplementation with Vitamin D3

To determine serum concentrations of leptin and ghrelin in patients with major depressive disorder (MDD) before and after vitamin D3 supplementation. A total of 72 participants were recruited in this study (40 MDD patients and 32 healthy controls). MDD was diagnosed by using Beck's Depression Inventory (BDI) scale. Blood samples were collected from all participants at the beginning of the study to determine baseline serum 25(OH)D3, leptin, and ghrelin concentrations. Patients were then treated weekly with vitamin D3 (50,000 IU) for 3 months, and blood samples were collected again by the end of the study. At baseline, serum leptin concentrations were significantly higher in MDD patients than in healthy controls. In contrast, serum ghrelin concentrations were significantly lower compared to those in healthy controls. After supplementation with vitamin D3 for three months, MDD patients showed improvements characterized by a decrease in their BDI's scores and an increase in their serum vitamin D and ghrelin concentrations. No effects of vitamin D3 supplementation were seen on serum leptin concentration. The antidepressant effects of vitamin D3 supplementation could be mediated by ghrelin but not leptin.