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Vitamin D and MS
Vitamin D: a natural inhibitor of multiple sclerosis.
Proc Nutr Soc 2000 Nov;59(4):531-5
Inheriting genetic risk factors for multiple sclerosis (MS) is not sufficient to cause this demyelinating disease of the central nervous system; exposure to environmental risk factors is also required. MS may be preventable if these unidentified environmental factors can be avoided. We have proposed that vitamin D may protect genetically-susceptible individuals from developing MS. Evidence consistent with this hypothesis comes not only from geographic studies, but also genetic and biological studies. Over-representation of the vitamin D receptor gene b allele was found in Japanese MS patients, suggesting it may confer MS susceptibility. However, the clearest evidence that vitamin D may be a natural inhibitor of MS comes from experiments with experimental autoimmune encephalomyelitis (EAE), a model of MS. Treatment of mice with 1,25-(OH)2D3 completely inhibited EAE induction and progression. The hormone stimulated the synthesis of two anti-encephalitogenic cytokines, interleukin 4 and transforming growth factor beta-1, and influenced inflammatory cell trafficking or apoptosis. If vitamin D is a natural inhibitor of MS, providing supplemental vitamin D to individuals who are at risk for MS would be advisable.
Although commonly called a 'vitamin' because it must be supplied from the diet, vitamin D (1, 25-dihydroxycholecalciferol) is acutally a hormone, and the author of this article makes a strong case (both biochemically and demographically) that physicians should be thinking about vitamin D therapy for their MS patients. Fish oil is an excellent vitamin D source, and diets rich in fish may lower MS prevalence or severity.
Vitamin D deficiency afflicts most MS patients, as demonstrated by their low bone mass and high fracture rates. MS prevalence increases with decreasing sunlight (i.e the rates of MS are higher in northern Europe versus southern Europe) suggesting that sunlight may be protective in MS.