Vitamin D: Nutrient, Hormone, and Immunomodulator

Nutrients. 2018 Nov 3;10(11):1656. doi: 10.3390/nu10111656.


The classical functions of vitamin D are to regulate calcium-phosphorus homeostasis and control bone metabolism. However, vitamin D deficiency has been reported in several chronic conditions associated with increased inflammation and deregulation of the immune system, such as diabetes, asthma, and rheumatoid arthritis. These observations, together with experimental studies, suggest a critical role for vitamin D in the modulation of immune function. This leads to the hypothesis of a disease-specific alteration of vitamin D metabolism and reinforces the role of vitamin D in maintaining a healthy immune system. Two key observations validate this important non-classical action of vitamin D: first, vitamin D receptor (VDR) is expressed by the majority of immune cells, including B and T lymphocytes, monocytes, macrophages, and dendritic cells; second, there is an active vitamin D metabolism by immune cells that is able to locally convert 25(OH)D₃ into 1,25(OH)₂D₃, its active form. Vitamin D and VDR signaling together have a suppressive role on autoimmunity and an anti-inflammatory effect, promoting dendritic cell and regulatory T-cell differentiation and reducing T helper Th 17 cell response and inflammatory cytokines secretion. This review summarizes experimental data and clinical observations on the potential immunomodulating properties of vitamin D.

Keywords: T cells; autoimmune diseases; gut microbiota; immune system; vitamin D.

Publication types

  • Review

MeSH terms

  • Adaptive Immunity / drug effects
  • Animals
  • Anti-Infective Agents / blood
  • Anti-Infective Agents / pharmacology
  • Anti-Inflammatory Agents / blood
  • Anti-Inflammatory Agents / pharmacology
  • Autoimmune Diseases / blood
  • Autoimmune Diseases / prevention & control
  • Disease Models, Animal
  • Host-Pathogen Interactions / drug effects
  • Humans
  • Immunologic Factors / blood
  • Immunologic Factors / pharmacology*
  • Microbiota / drug effects
  • Nutritional Status
  • Vitamin D / blood
  • Vitamin D / pharmacology*
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / drug therapy


  • Anti-Infective Agents
  • Anti-Inflammatory Agents
  • Immunologic Factors
  • Vitamin D