Recent genetic findings have come out to support observational evidence that low levels of vitamin D are associated with an increased risk of multiple sclerosis. According to new research by Brent Richards of McGill University, Canada, and colleagues, “genetically lowered vitamin D levels are strongly associated with increased susceptibility of multiple sclerosis.”

Multiple sclerosis, or MS, is a devastating autoimmune disease that affects nerves in the spinal cord and brain. There is currently no cure for MS, which usually begins to present itself between the ages of 20 and 40. Previous observational studies have suggested a link between lower vitamin D levels and multiple sclerosis risk, but the relationship is difficult to infer because patients may share another unknown characteristic that is actually responsible for increasing their risk of MS (known as a confounding variable).

The authors of the newest studies utilized a genetic technique called Mendelian randomization to reduce the possibility of confounding, allowing them to examine if there was an association between genetically reduced vitamin D levels and MS risk. Genetic levels of vitamin D can be measured by the level of 25-hydrovyvitamin D, which is the clinical determinant of vitamin D status. Researchers found that a genetic decrease in vitamin D by one standard deviation was associated with a 2-fold increased risk of MS.

Though the authors of the study suggested the association was strong, they also note that “ongoing randomized controlled trials are currently assessing vitamin D supplementation for the treatment and prevention of multiple sclerosis…and may therefore provide needed insights into the role of vitamin D supplementation.”

Could Sunlight Be The Key?

The idea that a lack of vitamin D could increase the risk of MS is an unwelcome one for many. After being warned of the dangers of sun exposure for their lives, how would those with genetically low levels of vitamin D be expected to safely increase those levels?

While sunlight is perhaps the best known way of acquiring vitamin D, it certainly isn’t the only way. For those who choose to protect their skin with sunscreen or avoid direct sunlight altogether, foods and vitamin supplements are alternative options for raising levels of vitamin D.

Foods including eggs, meat, and oily fish like salmon, mackerel and sardines have vitamin D, and supplements are both cost-effective and safe.

“Vitamin D is relatively cheap, safe, and many of us would be all the healthier if we could achieve the serum levels that our ancient ancestors presumably acquired when roaming outdoors in temperate climates, unclothed and eating a diverse diet including oily fish,” lead author Lauren Mokry of McGill University said to The Telegraph.

McGill adds that it may be a lot to expect therapeutic vitamin D to treat ongoing MS, but that the study will add weight to the argument for routine vitamin D supplementation as a broad, preventive health measure.

Source: Mokry L, Ross S, Ahmad O, Forgetta V, Smith G, Leong A, et al. Vitamin D and Risk of Multiple Sclerosis: A Mendelian Randomization Study. PLOS Medicine. 2015.