The evidence for low vitamin D levels being a risk factor for development of MS is becoming more compelling. In fact, some studies have shown that low vitamin D early in the disease course predicted worse MS clinical and MRI activity and disease progression.
A new study sheds light as to why this might be. There are 250 known genetic variants associated with MS, and now ones related to vitamin D metabolism are being defined. Four genetic variants have been found to affect vitamin D levels. Specifically, a decrease in a gene termed 250HD was associated with a two-fold increased risk of MS.
Vitamin D is one of several “modifiable” risk factors for development of MS. Others include obesity in the teens and early twenties and, especially, smoking. Supplementation with vitamin D seems to make sense for individuals at risk for MS, such as children of MS patients.
How much vitamin D should you take and what should be the target level? A multivitamin contains 600 units, but most MS experts advise much more, generally 5000 units and occasionally 10,000. Vitamin D levels are commonly done. For most laboratories, the lower normal is considered to be 30 but, in my opinion, target levels should be 50 to 100. Risks are very few. One study found no significant side effects with a 20,000-unit dose daily. Keep in mind that sitting in midday summer sun with your upper torso exposed promotes your skin to make 20,000 units of vitamin D.