Vitamin D and Autoimmune Diseases

Reference: “High-dose cholecalciferol supplementation significantly increases peripheral CD4+ Tregs in healthy adults without negatively affecting the frequency of other immune cells,” Prietl B, Treiber G, et al, Eur J Nutr, 2013 Sept 3; [Epub ahead of print]. (Address: Department of Endocrinology and Metabolism, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria).

Summary: In a double-blind, placebo-controlled study involving 60 healthy volunteers, 12 weeks of supplementation with high-dose cholecalciferol (vitamin D3, 140,000 IU/month) was found to be associated with significantly increased numbers of peripheral Tregs (regulatory T cells) in vivo, which play a key role in maintaing “self tolerance” and thereby reducing the risk of autoimmunity. While this beneficial effect was attained, the function of Tregs and the frequency of other immune cells remained unchanged. The authors also conducted studies in human peripheral blood mononuclear cells and found that cholecalciferol showed the same effects. The authors conclude, “Our results indicate a substantial effect of a supplementation with inactive vitamin D on the immune system of healthy humans in vivo and provide a rationale for future studies to investigate the immunomodulatory effects of vitamin D in autoimmune diseases.”