Vitamin D in Multiple Sclerosis

Posted by Elaine Moore Jan 15, 2007

For the past decade, researchers have been studying the association between low vitamin D levels and an increased risk of certain autoimmune diseases, particularly multiple sclerosis (MS) and Graves' disease. Looking at this association from a different angle, researchers at the Harvard School of Public Health have recently discovered that higher Vitamin D levels are associated with significantly lower rates of multiple sclerosis. In a study published in the December 2006 issue of Journal of the American Medical Association, researchers found that healthy young adults with the highest levels of 25-hydroxyvitamin D had a 62 percent reduction in MS compared with their counterparts with the lowest levels. Levels of he active hormone 25-hydroxyvitamin D were measured in this study.

The study, conducted on blood specimens that had been stored refrigerated, involved more than 7 million active duty military personnel. The subjects' blood samples had been collected twice (two years apart) and stored for possible future infectious disease testing. The study's principal investigator Alberto Ascherio, in an interview with Medscape, reported that "For the first time, we can envision the possibility of MS prevention." Of note, the results were most dramatic among younger adults in their early 20s. Also of note, of the 257 subjects who were found to have developed MS since the time of the blood collections, the average age of disease onset was 28.5 years.

The results of subjects of Hispanic, Caucasian or African-American races were compared to other military of the same sex and of their same racial profile. Parodoxically, African-Americans, a group known to have a lower risk of MS, had lower vitamin D levels than the other groups. It was suggested that the dark pigmentation characteristic of this group inhibited UV-B-induced subcutaneous production of vitamin D.

While using supplements as a preventive measure wasn't recommended at this time, the study's authors recommended increasing dietary sources rich in vitamin D, such as fatty fish, cod liver oil, shitake mushrooms and eggs. And while blood levels of 25 nmol/L of 25-hydroxy vitamin D are considered adequate by the Institute of Medicine, a review published in the July 2006 issue of the American Journal of Clinical Nutrition and described by Medscape suggests that blood levels of 90-100 nmol/L are necessary for bone utilization and fracture prevention.

The results of the study showed a 51 percent reduction in the incidence of MS in subjects whose 25-hydroxy vitamin D level was higher than 100 nmol/L. The highest reduction in MS was seen in subjects whose 25-hydroxyvitamin D level was higher than 100 nmol/L while they were still in their teens, suggesting the importance of adequate nutrition before full adulthood is reached.

Similar studies have shown the importance of vitamin D for muscle strength. Studies show that even in inactive adults older than 60 years, those subjects with the highest vitamin D levels exhibited significantly higher muscle strength, indicating the importance of vitamin D for normal muscle and musculoskeletal function.

Resources:

K. Munger, Lynn Levin, Bruce Hollis, Noel Howard, and Alberto Ascherio, Serum 25-hydroxyvitamin D levels and Risk of Multiple Sclerosis, JAMA, Dec 2006, 296;2832-2838.

Heike A Bischoff-Ferrari, Thomas Dietrich, E John Orav, Frank B Hu, Yuqing Zhange, Elisabeth Karlson and Bess Dawson-Hughes, Higher 25-hydroxyvitamin D concentrations are associated with better lower-extremity function in both active and inactive persons aged 60 years, American Journal of Clinical Nutrition, Sept 2005 952-958.

Caroline Cassels, Higher Vitamin D Levels Associated with Lower MS Risk, CME article, Medscape Medical News, Dec 20, 2006, http://www.medscape.com/viewarticle/549668