The short-term effect of high dose vitamin D3 supplementation in improving hypovitaminosis in patients with type 2 diabetes - A randomized clinical trial.

BACKGROUND

Type 2 diabetes (T2D) is an epidemic public health concern with considerable morbidity and mortality. Previous research has shown the association between T2D and vitamin D deficiency. This vitamin significantly affects insulin function, which plays a critical role in T2D development.

AIMS: A prospective double-blinded randomized controlled trial was conducted to test the hypothesis that vitamin D3 (VD3) supplementation can correct VD deficiency without the risk of hypervitaminosis.

METHODS

The participants of this study included 62 patients with T2D and hypovitaminosis D3. Of these patients, 30 received cholecalciferol (50,000 IU weekly for 8 weeks), and 32 received identical placebo tablets for 8 weeks. Before and after the intervention, patients were subjected to VD3 level assessment through fasting blood samples.

RESULTS

After 8 weeks of intervention, the mean changes in serum VD3 levels in the VD3 group were significant compared to the placebo group (i.e., 21.9 ± 10 vs. 1.2 ± 7 ng/ml, P < 0.001). Also, comparing serum D3 levels of the endpoint with the baseline revealed statistically significant changes in the VD3 group (40 ± 10 vs. 18.1 ± 6 ng/ml, P < 0.001) but no significant change in the placebo group (18.9 ± 7 vs. 20.1 ± 7, P = 0.37).

CONCLUSION

The results showed that administering a weekly dose of VD3 supplement could improve serum levels above 30 ng/ml in patients with T2D and compensate for vitamin deficiency without the risk of hypervitaminosis, which occurs at the levels above 100 ng/ml of 25(OH)D. However, further large-scale studies are needed to determine if these findings are applicable.