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20 December 2019

What is hypovitaminosis D?

Research over the years has shown that maintaining adequate levels of vitamin D may have a protective effect and lower the risk of developing multiple sclerosis. Hypovitaminosis or vitamin D deficiency however, are very common in some populations.

Hypovitaminosis is an insufficiency or deficiency of vitamin D.

People with MS are often vitamin D deficient and it is estimated that 1 billion people in the world are hypovitamosis D – it has been described as some as a pandemic. 


For 75 years we have known the frequency of MS varies by geographical region throughout the world, apparently increasing with distance from the Equator in both hemispheres. A hypothesis of link between MS and vitamin D first described in 1974. 

This is a summary of evidence relevant to MS prevention and low vitamin D levels. To see the evidence between vitamin D and disease activity and MS progression visit other areas of the site.

What causes low vitamin D levels?

It is often caused by inadequate UVB exposure, which might be due to:

  • Where you live in the world (latitude) 
  • Season
  • Time of day 
  • Dark skin
  • Obesity
  • Lifestyle – indoor job & leisure 
  • Sunscreen use 
  • Shade/shadow 
  • Clothing
  • Glass

It can also be caused by skin failing to produce vitamin D, accelerated loss of vitamin D, lack of dietary intake and health conditions. 

Hypovitaminosis as an environmental risk factor for MS

French researchers publishing in the world’s premier neurology journal Brain, have summarised the role of low vitamin D levels as a risk factor for multiple sclerosis. They note that, in addition to its primary role in calcium metabolism, vitamin D has anti-inflammatory, anti-infectious, immunomodulatory, and anti-cancer properties, and acts as a neurotransmitter involving many autoimmune diseases including, among others, multiple sclerosis, type 1 diabetes, rheumatoid arthritis and lupus.

They conclude that all the different types of research on vitamin D in MS have reached consistent conclusions, and have

“already allowed us to reach a global level of evidence that should be considered important”. 

In other words, it is time to stop investigating whether low vitamin D plays a key role in MS, simply accept that the evidence clearly shows it does, and get on with the clinical trials of its supplementation.

Read here

Reducing MS cases in populations

Public health researchers from Harvard have reviewed the literature on vitamin D in MS for Lancet Neurology

The researchers suggest that on the basis of current evidence, over 70% of cases of MS in Europe and the USA could be prevented by keeping people’s vitamin D levels above 100nmol/L, and that very large national or multinational controlled studies need to be done.

They also suggest studies of vitamin D supplementation, of the order of 4,000 to 10,000 IU daily, for people with a first demyelinating event, to prevent progression to definite MS, and for people with MS to slow disease progression.

  • An editorial suggested there may already be a case for widespread supplementation, especially in areas like Scotland, where vitamin D levels are known to be very low, and the incidence of MS very high.
  • Read here


1. Mansoor S, Habib A, Ghani F, Fatmi Z, Badruddin S, Siddiqui I, et al. Prevalence and significance of vitamin D deficiency and insufficiency among apparently healthy adults. Clin Biochem. 2010;43(18):1431–1435. doi: 10.1016/j.clinbiochem.2010.09.022

3.Pierrot-Deseilligny, C. & Souberbielle, J. C. Is hypovitaminosis D one of the environmental risk factors for multiple sclerosis? Brain 133, 1869–1888 (2010)

4. Wei MY, Giovannucci EL 2010 Vitamin D and multiple health outcomes in the Harvard cohorts. Mol Nutr Food Res 54:1114–1126