The effects of vitamin D3 supplementation on some metabolic and inflammatory markers in diabetic nephropathy patients with marginal status of vitamin D: A randomized double blind placebo controlled clinical trial.

AIMS: Diabetic nephropathy is known to be an independent risk factor in the progression of renal and cardiovascular disorders. Due to the association between vitamin D deficiency and diabetic nephropathy, vitamin D deficiency in the diabetic nephropathy population, this study conducted to examine the effects of Vitamin D3 on metabolic and inflammatory parameters in patients with diabetic nephropathy. METHODS: This eight-week, randomized, double-blind, placebo-controlled trial was carried out on 50 diabetic nephropathy patients with marginal status of vitamin D. Participants were randomly assigned to two groups: control and intervention. Participants received a vitamin D3 (50000 IU) supplement weekly on a specific day. Fasting blood samples were collected from all patients at their entry to the study, and eight weeks after intervention. RESULTS: Analyses showed significance differences in physical activity between the intervention and placebo groups (P = 0.018). There were no significant differences between the percentage changes of HbA1c, insulin and, inflammatory parameters such as TNF-α and IL-6 (P > 0.05), while the percentage change of FBS was significantly higher in the placebo group compared to the treatment one (P < 0.0001). Lower levels of FBS (P < 0.0001), insulin (P < 0.069), HOMA-IR (P < 0.001), TNF-α (P< 0.002) and IL-6 (P < 0.037) were found after supplementation in treatment group. However, the phosphorous and protein percentage change in urine were lower (P = 0.07) and higher (P = 0.003) between groups. CONCLUSIONS: It was found that vitamin D supplementation can be regarded as an effective way to prevent the progression of diabetic nephropathy by reducing levels of proteinuria, and inflammatory markers such as TNF-α and IL-6.