Vitamin D in Autoimmunity

This week from Dr. Cerami and Utah Sports and Wellness

 

From: Frontiers in Immunology, January 2017

 

Quick Summary:

The prevalence of autoimmunity is increasing in the Western countries. The role of vitamin D goes beyond the regulation of calcium homeostasis and bone health. Vitamin D is important in the modulation of the immune system. Autoimmune diseases, including rheumatoid arthritis (RA), multiple sclerosis (MS), and Crohn’s disease (CD), result from an aberrant activation of the immune system, whereby the immune response is directed against harmless self-antigens. This results in inflammation, tissue damage, and loss of function of the affected organs or joints. There is a high prevalence of vitamin D deficiency in patients suffering from autoimmunity. Vitamin D deficiency has now been linked to not only bone health but also, cancer, cardiovascular diseases, and autoimmune diseases. Vitamin D receptors are found on blood lymphocytes, allowing vitamin D to influence the immune system and immune-related diseases.  “Virtually all immune cells express the vitamin D receptor, making them susceptible to [active form of vitamin D]-mediated modulation.” Early evidence suggested that low vitamin D increased the risk of autoimmune diseases.

These authors also note:

  • The [active form of vitamin D] initiates its signaling cascade by binding to the vitamin D receptor, which is a nuclear receptor.
  • “The best known function of [active form of vitamin D] is the maintenance of calcium homeostasis by facilitating the absorption of calcium in the intestine.”
  • When [active form of vitamin D] levels are low, calcium will be mobilized from the bone rather than the intestines.
  • Vitamin D was used to treat mycobacterial infections such as tuberculosis, before antibiotics were discovered.
  • The vitamin D receptor is expressed in almost all human cells.
  • “Virtually all immune cells express the vitamin D receptor, making them susceptible to [active form of vitamin D]-mediated modulation.”
  • “Next to UV exposure, vitamin D can also be obtained from dietary sources and supplements.”
  • These authors present the literature evidence for vitamin D supplementation in the treatment and prevention for the following diagnosis:
    • Crohn’s Disease
    • Diabetes Type-I
    • Multiple Sclerosis
    • Rheumatoid Arthritis
  • Systemic Lupus Erythematosus
  • Immune cells, including monocytes, dendritic cells, macrophages, B cells, and T cells, can convert 25(OH)D3 [inactive precursor form of vitamin D] into [active form of vitamin D], allowing “local regulation of the concentration of [active form of vitamin D] at the site of inflammation and illustrates an important role for the cells of the immune system in the systemic effects of vitamin D.” [Important: this means that not only the liver has the ability to make the active form of vitamin D, so do these immune system cells]
  • Vitamin D levels [25(OH)D3, the inactive precursor form of vitamin D]: Calcium homeostasis guidelines indicate that:
    • < 50 nmol/L deficiency [<20 ng/ml]
    • 50 and 74 nmol/L insufficiency [20 – 30 ng/ml]
    • >75 nmol/L sufficient [>30 ng/ml]

    However, these numbers do not apply to optimum immunity, which require much higher levels.

2018-09-11T16:16:10+00:00September 11th, 2018|