Vitamins are components of food that are needed in very small amounts for growth and to maintain good health. Vitamin D has several important functions, for example, it helps regulate the amount of calcium and phosphate in the body to keep bones and teeth healthy. Lack of vitamin D can lead to deformed bones in children (known as rickets) and a condition called osteomalacia in adults. However, vitamin D also plays a role in regulating the immune system so its possible role in MS is the subject of much research and debate.
Vitamin D is created in the skin when exposed to ultraviolet B radiation in sunlight. In the UK, between May and September, about 20 to 30 minutes a day spent outdoors in short sleeves in direct sunshine in the middle of the day will meet vitamin D needs for most fair skinned people. Between October and April, the sunlight in the UK usually has too low a level of ultraviolet B (UVB) for vitamin D to be made.
Vitamin D is also found in some foods including oily fish, such as salmon and sardines, and cod liver oil. Lower amounts are found in eggs, fortified fat spreads and breakfast cereals and in powdered milk.
How this study was carried out
This paper is a review which summarises the evidence for the possible role of vitamin D in MS. It looks at whether lack of vitamin D is associated with an increased risk of getting MS but also whether lack of vitamin D makes a difference to the course of MS after it has been diagnosed.
What was found
The research paper provides plenty of detail and has sections on the following:
- Background information on MS
- Background information on vitamin D
- Linking vitamin D and MS: immunoregulatory functions of vitamin D
- Linking vitamin D and MS: how do genes contribute?
- Linking vitamin D and MS: what do animal models tell us?
- Linking vitamin D and MS: the clue to geographic and seasonal associations?
- Linking vitamin D and MS: the impact of vitamin D intake and serum level
- Linking vitamin D and MS: what do interventional trials tell us?
The authors conclude that there is evidence, including from animal and epidemiological studies (studies of the human population), that suggests that higher levels of vitamin D in the blood are associated with a lower risk of developing MS.
They also suggest that higher levels of vitamin D in the blood are helpful for people who already have a diagnosis of MS as this seems to improve the course of their disease.
Both of these observations are based on comparing people who have naturally higher or lower vitamin D levels. As vitamin D is a safe, cheap and easy to take supplement, the review examines whether there is any evidence that taking vitamin D supplements helps to prevent or treat MS.
The researchers suggest that the evidence that vitamin D supplements could be used to prevent MS is quite compelling. However, the only way this could be rigorously tested is if vitamin D supplements were given to a large population and then the number of newly diagnosed cases of MS went down.
The review's authors believe that there is conclusive evidence that naturally higher levels of vitamin D in the blood lead to a better disease course in MS. However, they suggest that the completed clinical trials of vitamin D supplements are inconclusive and partly contradictory. They express their hope that the additional trials still underway will allow a conclusion to be drawn one way or the other.
What does it mean?
In the light of all the evidence, the authors consider whether people with MS should take vitamin D (or not) right now. They suggest that, especially in the winter months when vitamin D cannot be obtained by being outdoors and exposed to sunlight, it is reasonable to raise vitamin D levels by taking supplements for those people whose levels are known to be low. They do not suggest what level of supplements people should generally take. However, they do give some guidance to clinicians. To put this into practice would require someone with MS to have a test for vitamin D levels in their blood and then take an appropriate amount of supplements to raise the level.
More about vitamin D
Vitamin D is a hot topic in MS. There are a whole range of opinions on whether taking vitamin D supplements could make a difference and, if so, how much someone should take. The review published this week is a useful summary of the research so far but it does not give clear guidance for people with MS to follow.
The recommended daily intake of vitamin D for the general population in the UK (400IU) is based on reducing the risk of rickets and is widely considered to be too low. In August 2012, the European Food Safety Authority increased the Tolerable Upper Intake Levels (the levels that can be taken daily without causing harm) to 4000IU. Some authors feel this is also too low.
NICE has begun a review that will look at the role of vitamin D in general rather than specifically in MS. A consultation on the draft version of this is expected towards the end of 2013.
Labelling of vitamin D on packs of supplements can be very confusing as the amount they contain may be expressed in micrograms or International Units. 40 IU (International Unit) is equivalent to 1 microgram (µg) of Vitamin D2 or D3. Research papers or tests for vitamin D levels in serum (a component of the blood) are usually expressed as their concentration, either ng/ml or nmol/l. A health professional should be able to advise on whether to have a vitamin D test and whether supplements are advisable.
More information on vitamin D from the MS Trust
An update on vitamin D is available in our newsletter Open Door.
There is also a summary in the A to Z of MS.
More information on diet is available in our diet A-Z.
Other sources of information on vitamin D
They have general guidance on who might benefit from vitamin D supplements including pregnant women, young children and anyone who does not get much exposure to sunlight, including people who are housebound.
Research by topic areas...
Symptoms and symptom management
Tapia CI, Khalaf K, Berenson K, et al.
Health-related quality of life and economic impact of urinary incontinence due to detrusor overactivity associated with a neurologic condition: a systematic review.
Health Qual Life Outcomes. 2013 Jan 31;11(1):13. [Epub ahead of print]
[No authors listed]
Botulinum toxin type A and neurogenic urinary incontinence: sometimes beneficial, if used safely.
Prescrire Int. 2013 Jan;22(134):12-3.
Heigl F, Hettich R, Arendt R, et al.
Immunoadsorption in steroid-refractory multiple sclerosis: Clinical experience in 60 patients.
Atheroscler Suppl. 2013 Jan;14(1):167-73.
Disease modifying treatments
Bermel RA, You X, Foulds P, et al.
Predictors of long-term outcome in multiple sclerosis patients treated with interferon beta.
Ann Neurol. 2013 Jan;73(1):95-103.
Arun T, Tomassini V, Sbardella E, et al.
Targeting ASIC1 in primary progressive multiple sclerosis: evidence of neuroprotection with amiloride.
Brain. 2013 Jan;136(Pt 1):106-15.
Jadidi E, Mohammadi M, Moradi T.
High risk of cardiovascular diseases after diagnosis of multiple sclerosis.
Mult Scler. 2013 Jan 30. [Epub ahead of print]
Gabelic T, Krbot M, Sefer AB, et al.
Ocular and cervical vestibular evoked myogenic potentials in patients with multiple sclerosis.
J Clin Neurophysiol. 2013 Feb;30(1):86-91.
Foley FW, Zemon V, Campagnolo D, et al.
The Multiple Sclerosis Intimacy and Sexuality Questionnaire -- re-validation and development of a 15-item version with a large US sample.
Mult Scler. 2013 Jan 31. [Epub ahead of print]
Causes of MS
Langer-Gould A, Brara SM, et al.
Childhood obesity and risk of pediatric multiple sclerosis and clinically isolated syndrome.
Neurology. 2013 Jan 30. [Epub ahead of print]
Genova HM, Lengenfelder J, Chiaravalloti ND, et al.
Processing speed versus working memory: contributions to an information-processing task in multiple sclerosis.
Appl Neuropsychol Adult. 2012 Apr;19(2):132-40.
Morley A, Tod A, Cramp M, et al.
The meaning of spasticity to people with multiple sclerosis: What can health professionals learn?
Disabil Rehabil. 2013 Feb 4. [Epub ahead of print]
D'Alessandro R, Vignatelli L, Lugaresi A, et al.
Risk of multiple sclerosis following clinically isolated syndrome: a 4-year prospective study.
J Neurol. 2013 Feb 3.[Epub ahead of print]
Provision of care
The health promotion work of the district nurse: interpreting its embeddedness.
Prim Health Care Res Dev. 2013 Feb 4:1-11. [Epub ahead of print]