[Vitamin D like one of few prevention possibilities for autoimmune diseases?].

Data from elderly Americans of an age of ≥50 years that were included in a large nationwide, randomized, double-blind, placebo-controlled prevention trial, show that vitamin D supplementation, alone or in combination with omega-3 fatty acids, reduces autoimmune disease risk with 22%. These Americans were treated with 2000 IU/day cholecalciferol (vitamin D) for a period of 5 years alone or in combination with 1g/day omega-3 fatty acids. Both treatments resulted in a significant reduction of the incidence of autoimmune diseases. The findings were more pronounced after two years after the start of the supplementation. Having a lower body index seems to be beneficial for the vitamin D effects. The question is via which pathophysiological mechanism(s) does vitamin D work. More and more of the secrets of the effects of vitamin D on the immune system and in particular on T cells are becoming identified and this study motivates to dig further.