The Effects of Vitamin D Supplementation in Newly Diagnosed Type 1 Diabetes Patients: Systematic Review of Randomized Controlled Trials

Rev Diabet Stud. 2017 Summer-Fall;14(2-3):260-268. doi: 10.1900/RDS.2017.14.260. Epub 2017 Oct 10.


Aim: The aim of this study was to examine the effects of vitamin D supplementation in patients newly diagnosed with type 1 diabetes (T1D) assessed by insulin needs and changes in glycemic indices, as evidenced by randomized controlled trials (RCTs).

Methods: A total of 7 RCTs were retrieved from PubMed/Medline and EBSCO databases by MeSH term search, and were reviewed systematically. The RCTs included examined the effects of alphacalcidole (n = 2), cholecalciferol (n = 2), and calcitriol (n = 3) supplementation on changes in daily insulin dose (DID), fasting Cpeptide (FCP), stimulated C-peptide (SCP), and HbA1c. In total, 287 individuals, diagnosed with T1D within a period of 4 weeks to 1 year and aged between 5 to 38 years, were examined.

Results: Significant positive effects on DID, FCP, and SCP levels were observed after supplementation with alphacalcidole and cholecalciferol, whereas supplementation with calcitriol showed no effect.

Conclusions: Vitamin D supplementation in the form of alphacalcidole and cholecalciferol appears to be beneficial in the treatment of T1D patients by attenuating the natural history of the disease.

Publication types

  • Review
  • Systematic Review

MeSH terms

  • C-Peptide
  • Cholecalciferol
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Dietary Supplements*
  • Humans
  • Randomized Controlled Trials as Topic
  • Vitamin D / therapeutic use*
  • Vitamins / therapeutic use*


  • C-Peptide
  • Vitamins
  • Vitamin D
  • Cholecalciferol