The effect of vitamin D supplementation on peripheral regulatory T cells and ? cell function in healthy humans: a randomized controlled trial.
Diabetes Metab Res Rev. 2011 Nov;27(8):942-5. doi: 10.1002/dmrr.1276.
Bock G, Prietl B, Mader JK, Höller E, Wolf M, Pilz S, Graninger WB, Obermayer-Pietsch BM, Pieber TR.
Department of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria. gerlies.bock at medunigraz.at
Increasing evidence supports the role of vitamin D (vitD) in modifying the risk to develop type 1 diabetes (T1D) and other autoimmune diseases. VitD3 might stimulate regulatory T cells (Tregs), a central player in the maintenance of self-tolerance. In addition, direct effects of vitD on ?-cell function are postulated.
The aim of our study was to evaluate the effect of a high dose vitD supplementation on Tregs frequency (%Tregs) and ?-cell function assessed by a mixed meal tolerance test (MMTT) in healthy humans.
A double-blind, placebo controlled trial was performed in 59 healthy adult subjects (49% females). Subjects received oral vitD3 (140,000 IU monthly) or placebo for 3 months. %Tregs within 20,000 CD4+ T cells of peripheral blood was determined by multi-parametric FACS-analysis. A liquid MMTT was carried out before and after treatment.
%Tregs increased significantly in the vitD group, but remained unchanged in the placebo group. Fasting C-peptide concentrations did not change significantly in either group. Similarly, the mean AUC for C-peptide after 3 months and the change in mean values from baseline to the end of the treatment were comparable in both groups.
A short time high dose vitD3 supplementation significantly increased the frequency of Tregs, but did not further improve ?-cell function in apparently healthy subjects. The immunomodulatory potential of vitD might be an important mechanistic link for the association of vitD and T1D.
Copyright © 2011 John Wiley & Sons, Ltd.
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140,000 IU monthly = 4700 daily