“Chicken or egg; association vs. causation vs. reverse causation. There are a lot of believers out there when it comes to vitamin D and MS disease activity. At first glance it would look as if low vitamin D levels are the cause of MS and drive MS disease activity. This has led to the hypothesis that simply taking vD supplements will prevent a large proportion of MS and will work as a disease-modifying drug. Unfortunately the evidence that vD works as a DMT is very poor; we need large adequately powered studies to answer this question. I personally don’t think the current trials are large enough and I am still not convinced we know what dose of vD will answer the question definitively.”
Epub: Marsh-Wakefield & Byrne. Photoimmunology and Multiple Sclerosis. Curr Top Behav Neurosci. 2015 Jan 22.
The ultraviolet (UV) radiation contained in sunlightSunlight is a powerful immune suppressant. While exposure to UV is best known for its ability to cause skin cancer, it is also associated with protection against a range of autoimmune diseases, particularly multiple sclerosis (MS). Although the precise mechanism by which sunlightSunlight affords protection from MS remains to be determined, some have hypothesised that UV immunosuppression explains the “latitude-gradient effect” associated with MS. By stimulating the release of soluble factors in exposed skin, UV activates immune suppressive pathways that culminate in the induction of regulatory cells. Regulatory cells in distant tissues. Each and every one of the immune suppressive cells and molecules activated by UV exposure are potential targets for treating and preventing MS. A thorough understanding of the mechanisms involved is therefore required if we are to realise the therapeutic potential of photoimmunology.