The effect of vitamin D supplementation on adiposity, blood glycated hemoglobin, serum leptin and TNF-α in type 2 diabetic patients

Since tumor necrosis factor‑α (TNF‑α) could be one of the risk factors at the development of diabetes complications; as well as serum leptin deficiency is related to increased susceptibility to infections in diabetic patients, they are potential indices from the preventive medicine viewpoint. This study was conducted to represent the effect of supplemental vitamin D3 on serum leptin, TNF‑α and adiposity in type 2 diabetic patients. In this randomized double‑blind placebo‑controlled trial, study sample was selected through type 2 diabetic patients (n = 51). A total of 26 patients were orally supplemented by vitamin D3 (400 IU/d) (vitamin D group) and 25 patients by placebo (placebo group) for 14 weeks. The blood glycated hemoglobin (HbA1c) and the serum ionized Ca, leptin, TNF‑α, and serum 25‑hydroxyvitamin D (25[OH] D) were measured at the two groups in the baseline and postintervention stages. It was shown that despite of theplacebo group, serum 25(OH) D and serum leptin was significantly increased (P = 0.001 and P = 0.002, respectively), while serum TNF‑α was decreased significantly (P = 0.001) in vitamin D group. The remaining parameters, including body fat mass and HbA1c had no alterations between baseline and postintervention stages in vitamin D group. This study may advocate vitamin D supplementation among type 2 diabetic patients due to its beneficial effects on prevention of diabetes complications.