Research appearing in the Journal of the American Medical Association (2006 Dec 20;296(23):2832-8) found that higher vitamin D levels in the serum is associated with a decreased risk of multiple sclerosis (MS). The researchers identified 257 subjects who were diagnosed with MS between 1992 and 2004. The subjects with the MS were then compared to healthy subjects of similar ethnicity, age and sex. They found that in the white participants, a 50 nanomole-per-liter increase in serum vitamin D represented a 41% decrease in the risk of MS. This relationship did not hold for blacks or Hispanics.

This finding supports data from the Nurse’s Health Study published in the Jan. 13, 2004 issue of Neurology. Women without MS symptoms completed questionnaires on diet and use of multivitamin supplements. Of 187,563 women, 173 women developed MS during the study. Women who took 400 IU or more of vitamin D per day from vitamin supplements were 40% less likely to develop MS than those who used no supplements.  There have been earlier studies on mice supporting this idea. Also, some researchers have linked low vitamin D levels to MS.

Periods of exacerbation in MS patients have been linked to periods of low vitamin D levels and periods of remission have been linked to high vitamin D levels. Because the incidence of MS increases as you get farther from the equator, some scientists think that sunlight exposure and high levels of vitamin D may reduce the risk of MS.