Vitamin D Resistance as a Possible Cause of Autoimmune Diseases: A Hypothesis Confirmed by a Therapeutic High-Dose Vitamin D Protocol.

Vitamin D (cholecalciferol) is a secosteroid and prohormone which is metabolized in various tissues to the biologically most active vitamin D hormone 1,25(OH)D (calcitriol). 1,25(OH)D has multiple pleiotropic effects, particularly within the immune system, and is increasingly utilized not only within prophylaxis, but also within therapy of various diseases. In this context, the latest research has revealed clinical benefits of high dose vitamin D therapy in autoimmune diseases.