Monday, January 01, 2007

Higher levels of vitamin D reduce the risk of multiple sclerosis

People with higher circulating vitamin D levels are significantly less likely to develop multiple sclerosis, according to a new study by Harvard researchers.

The RDA for vitamin D was recently increased in the elderly to 600 IU per day. Many reports and most experts suggest levels between 600-1,000 IU per day, especially for those in northern climates or with poor sunlight exposure. Typical dietary intake is between 100-200 IU per day. A report published in the December 20, 2006 issue of the Journal of the American Medical Association concluded that having a higher serum level of vitamin D is associated with a lower risk of multiple sclerosis (MS) among men and women. The finding adds to those of previous studies that suggest that the vitamin may have a protective effect against the disease. Harvard researchers studied more than 250 individuals diagnosed with multiple sclerosis between 1992 and 2004. The team determined that for every 50 nanomole per liter increase in serum vitamin D among white participants there was a 41 percent decrease in the risk of MS. Whites in the top one-fifth of serum vitamin D concentrations had the lowest risk of the disease, and those in the lowest fifth had the greatest risk. Those with the highest vitamin D levels experienced a 62 percent lower risk of MS compared to those in the group with the lowest levels. The results of this study suggest that high circulating levels of vitamin D are associated with a lower risk of multiple sclerosis.

Source: Serum 25-Hydroxyvitamin D Levels and Risk of Multiple Sclerosis, Kassandra L. Munger, Lynn I. Levin, Bruce W. Hollis, Noel S. Howard, Alberto Ascherio, JAMA 2006;296:2832-2838.