Effects of vitamin D supplementation on depressive symptoms in type 2 diabetes mellitus patients: Randomized placebo-controlled double-blind clinical trial

Abstract Aim Diabetes increases the odds of depression and depression is often associated with poor glycemic control and complications of diabetes. Vitamin D is also believed to improve glycemic control and ameliorate depressive symptoms. Therefore, we examined effects of vitamin D monotherapy (without antidepressant drugs) on depressive symptoms in Type 2 diabetic patients with mild to moderate depressive symptoms. Methods We conducted 12 weeks, placebo-controlled, double-blind, randomized trial on 68 subjects with T2DM and mild to moderate depressive symptoms. Subjects received 100 μg (4000 IU) vitamin D (n = 32) or placebo (n = 34) daily. Beck Depression Inventory-II (BDI–II–PERSIAN) was applied for assessment of the severity of depression. Depression scores and metabolic profiles were measured at the beginning and end of trail. Results after 3 months of vitamin D supplementation, mean values of 25(OH) D increased from 15.5 ± 8.8 to 32.2 ± 8.9 ng/ml (p-value Conclusions In conclusion, supplementation of vitamin D in T2DM patients may protect these patients against the onset of major depressive disorder (MDD), with noticeable favorable effects on measures of metabolic profiles. Trial registration NCT03008057