Research published in the Journal of the American Medical Association (December 20, 2006; 296[23]:2832–2838) found that higher serum vitamin D levels were associated with a reduced risk of multiple sclerosis (MS).
Researchers identified 257 individuals diagnosed with MS between 1992 and 2004 and compared them with healthy controls matched for age, sex, and ethnicity. Among white participants, a 50 nmol/L increase in serum vitamin D was associated with a 41% reduction in MS risk. This association was not observed among Black or Hispanic participants.
These findings are consistent with data from the Nurses’ Health Study published in Neurology (January 13, 2004). In that study, women without MS symptoms completed questionnaires regarding diet and supplement use. Of 187,563 women followed, 173 developed MS during the study period. Women who consumed 400 IU or more of vitamin D per day from supplements were approximately 40% less likely to develop MS compared to those who did not use supplements.
Earlier experimental studies in animal models have also supported a potential relationship between vitamin D status and MS risk, and additional observational research has linked low vitamin D levels with the disease.
In people with established MS, disease activity appears to fluctuate with vitamin D status. Periods of exacerbation have been associated with lower vitamin D levels, while periods of remission have been linked to higher levels. Because MS prevalence increases with distance from the equator, some researchers have proposed that sunlight exposure—and the resulting increase in vitamin D production—may play a role in modifying MS risk.
