All of us get our vitamin D through diets, supplements, and exposure to sunlight. There are also many different types of vitamin D, and different ways to get them. Vitamin D2 is found in plants and fungi. Vitamin D3 is found in meats, and is also produced when skin and eyes are exposed to ultraviolet light. These are the simplicities of vitamin D, but it does get more complicated than that as well. Both vitamins D2 and D3 are hydroxylated in the liver and then become what is known as 25-hydroxyvitamin-D (25-D). 25-D and 1, 25-D serves as the native ligands for the Vitamin D Receptor (VDR).
Vitamin D Nuclear Receptor (VDR)
When active, the Vitamin D nuclear receptor (VDR) affects the transcription of at least 913 genes, if not more. Either directly or indirectly, the vitamin D endocrine system regulates 3% of the human genome. It also impacts the processes from calcium metabolism to the expression of key antimicrobial peptides (also known as the host defense peptides), which are part of the innate immune response. When the VDR is active, it also transcribes TLR2, which recognizes gram-positive bacteria.
Recent research on vitamin D addresses two observations about 25-D. First of all, the levels of 25-D are significantly lower in people with autoimmune disease. And second, people who are given vitamin D have lower rates of autoimmune disease and fewer markers of inflammation.
Although this may seem like supplemental vitamin D is beneficial, Professor Trevor G. Marshall, PhD wonders if the low 25-D levels in autoimmune disease may be the result of the disease process itself, and that the drop in inflammation among individuals taking vitamin D comes from its ability to slow the immune function.
It is widely explained that autoimmune diseases happens when the immune system and the VDR are overactive. These researchers argue that having additional vitamin D calms the immune response by deactivating the VDR. The reduction in autoimmune disease and inflammation symptoms in people taking vitamin D results from a very temporary suppression of our innate immune response. The innate immune system’s response to chronic pathogens is by secreting chemokines and cytokines to clear them from the body. If it doesn’t work, then the result is a disease stalemate that explains the chronic inflammation in autoimmune disease.
For more information on Professor Trevor Marshall’s Vitamin D research visit: www.trevormarshall.com
Written by: Colbi Judd
Jeff Bland interview with Trevor Marshall on Vitamin D.
Paul J. Albert, Amy D. Proal, Trevor G. Marshall. Vitamin D: the alternative hypothesis, www.trevormarshall.com