The Sun, Vitamin D, and MS

Vitamin D insufficiency or deficiency is common in the regions of northern Europe, since 90% of this vitamin D is formed in the skin under the effect of the sun's ultraviolet rays. Low vitamin D blood levels in childhood and adolescence are a predisposing factor in the development of multiple sclerosis in adulthood.

In a Finnish study published in March 2016, mothers who are deficient in vitamin D at the beginning of their pregnancy almost double the risk of multiple sclerosis in their future children. This vitamin is not only important for calcium and bone metabolism, but also for the maturation of the immune system. It has immunomodulatory properties.

The prevalence of the disease is 2 times greater in northern and eastern France than in the Provence-Côte d'Azur region, and this prevalence is inversely proportional to ultraviolet radiation in these geographical regions, and to the average vitamin D blood concentration in the populations concerned.

‍In people who already have the disease, low vitamin D levels are associated with greater disease activity detected by brain magnetic resonance.

‍This inverse relationship was particularly observed in two studies concerning interferon beta1b (Betaferon), the BENEFIT and BEYOND studies. The presence of high blood vitamin D levels, between 40 and 60 ng/ml, decreased the number of active lesions on brain imaging by almost 50%. These studies also showed a synergistic effect of vitamin D and interferon beta, effects not yet demonstrated with glatiramer acetate or with the other immunomodulatory treatments used in the disease.

There is no toxicity of vitamin D, even taken in high doses, up to 20,000 units per day (one ampoule of D cure contains 25,000 units). In the current state of our knowledge, maintaining a serum vitamin D level between 40 and 60 ng/ml in patients with multiple sclerosis is a justified precautionary principle. The same goes for their children. Two placebo-controlled scientific studies concerning the addition of vitamin D in the treatment of patients with multiple sclerosis are in progress or in the process of being finalized (EVIDIMS and SOLAR). Their results will be important in order to generalize the use of vitamin D as an adjunct treatment in multiple sclerosis.

‍Prof Christian Sindic