Vitamin D
Both environmental and genetic factors seem to play a role in the development of multiple sclerosis (MS), but determining an exact cause of the disease has been elusive. Now new evidence suggests that vitamin D may play a direct role in regulating a gene known to be associated with MS. This finding helps bridge the gap between environmental and genetic risk factors, and strengthens the hypothesis that vitamin D could be instrumental in MS prevention.
MS is an autoimmune disease that attacks myelin, a component of the nervous system essential for the conduction of neural impulses. Onset of MS usually occurs between the ages 18 and 35, and is more prevalent in females than males.
One of the most interesting epidemiological findings associated with MS is that it is more common in regions farthest from the equator, with a few notable exceptions. Climate, sunlight and vitamin D are all suspected candidates in the occurrence of MS, as are genetics and diet. Importantly, the relationship between geographical location and MS risk seems to be most significant in early childhood years. After age 15, risk of MS for immigrants is closer to that of their home country than to that of their new country.
Sunshine is the most common source of vitamin D for humans. Vitamin D is created when ultraviolet B (UVB) light contacts skin. Dietary vitamin D is rare, though it can be obtained at significant levels with certain foods, particularly oily fish (e.g. sardines and salmon). Notably, Norway and many Asian countries have relatively low prevalence of MS. It has been suggested that fish consumption is the reason for these regional discrepancies that cannot be explained by sun exposure. This makes vitamin D a particularly strong candidate for MS prevention.
In addition to environmental factors, certain genetic risks are linked to MS. In particular, proteins associated with the body’s immune cells are mutated in many MS cases. Mutations in these proteins disrupt the ability of immune cells to determine which particles in the body are foreign and which are “self.” When this happens, the cells get confused and begin to attack their own body’s tissues.
A new article published last week in PLoS Genetics investigated the relationship between vitamin D and the genetic variants associated with MS. They found that vitamin D directly interacts with these genes at a molecular level, providing insight into the mechanism by which vitamin D may affect the disease. Though it is still not clear what specific role vitamin D plays in its interaction with MS genes, a new avenue of exploration has opened up into MS etiology.
The tie between vitamin D and MS is still vague, but it is a good idea to ensure your vitamin D levels are adequate. People living at latitudes greater than 40 degrees from the equator (San Francisco is on the border) should be taking vitamin D supplements. This is true for many reasons; MS is not the only disease that is linked to low vitamin D levels.
Vitamin D pills are now easy to find, and can be obtained at both Trader Joe’s and Whole Foods. Take one or two oil-based 1000IU vitamin D supplements daily. Men should avoid vitamin D supplements that contain calcium, because excess calcium increases risk of prostate cancer.
Do you take vitamin D supplements?
UPDATE: This article can also be found in Synapse.
