What is multiple sclerosis?
Multiple sclerosis (MS) is a condition that affects the nerves. The body’s immune system, which usually fights infection, attacks the nerve cells in the brain and spinal cord. Nerve cells have a protective covering called the myelin sheath, which helps them deliver messages to different parts of the body. As the myelin is destroyed and the nerve cells lose their insulation, it becomes more and more difficult for nerve cells to work properly. When the nerve cells in the brain and spinal cord aren’t able to do their job, many parts of the body can be affected. This can cause problems with one’s ability to walk, eat, see and urinate. MS is not fatal or contagious, and symptoms develop slowly in most people.
There are two main types of MS:
- Relapsing-remitting: This is the most common type of MS in which the symptoms come and go. The term, relapse, is used when symptoms appear. When symptoms fade away, this is called remission. When an individual goes into remission, one may recover completely; however, some may not recover fully. Relapses can last for days or weeks, and the severity can range from mild to severe. On average, people with relapsing remitting MS have one or two attacks a year. The symptoms may gradually worsen over time, and the recovery from relapse may become less successful.
- Progressive: There are two kinds of progressive MS, primary and secondary. Primary progressive MS is when the symptoms worsen from the start and one doesn’t go into remission. This means that one gradually becomes more disabled as time goes on. Secondary progressive MS is where one initially has relapsing remitting MS for quite a few years, but then begins to have fewer periods of relapse and remission and gradually becomes more disabled. One may not recover completely after a relapse, and eventually, periods of relapse followed by remission may stop altogether. Instead, the condition will gradually worsen. Only 15% of MS cases are initially diagnosed as progressive.
How common is multiple sclerosis?
Roughly 250,000 people in the United States have MS. Most people with MS are diagnosed between the ages of 20 and 40. The chance of developing MS is about 1 in 750 in the United States, but the risk is greater if one:
- has a history of infection with the Epstein-Barr virus
- has a first-degree relative (parent, brother or sister, non-identical twin) with the disease
- is female
- was raised in far North regions (MS is more common farther from the equator)
What are the symptoms of multiple sclerosis?
Because the nerves in any area of the brain or spinal cord can be damaged in MS, one may develop different symptoms, including:1
- loss of balance
- partial of full paralysis
- numbness, weakness and tingling in the arms and legs
- problems speaking and swallowing
- loss of vision
- problems thinking and concentrating
- problems urinating
- sexual problems, such as loss of desire or difficulty getting or keeping an erection
If one notice any of these symptoms, it’s important that one talk to their doctor.
MS is an unpredictable condition that affects each person differently. Depending on how severe the MS is, one may have only a few of the symptoms or many of them. In some people MS develops very slowly, while others become disabled by their symptoms more quickly.
What causes multiple sclerosis?
Scientists and doctors don’t know for sure what causes MS. However, it’s thought that it may be a combination of the genes and the environment that cause it to develop. Some researchers believe that a virus may trigger MS in people that carry certain genes.
These are some of the other things that may influence whether one develops MS:
- Sex: More women than men have MS, so it’s possible that the hormones play a role in its development.
- Race: Rates are highest among blacks, moderate for whites and lower for Hispanic- and Asian-Americans. African Americans experience greater multiple sclerosis-associated disability than Caucasians. Both skin pigmentation and diet may affect the risk of MS.
- Age: MS can develop at any age, but it most commonly affects people between the ages of 20 and 40.4
- Birth location: MS is more common in areas north of the equator and in people born in early spring. This suggests that there may be a link between the amount of sunshine one receives and the likelihood of developing MS.
What is the link between multiple sclerosis and vitamin D?
Some researchers think vitamin D may have potential to prevent MS or reduce the number and severity of relapses.
Vitamin D plays an important role in developing healthy bones, but researchers are also starting to uncover the role of vitamin D in many other areas of health. It’s now known that vitamin D plays a role in the immune and nervous systems, although the mechanism of action is still being studied.
Some cells in the immune and nervous systems have receptors for vitamin D. Receptors are found on the surface of a cell where they receive chemical signals. By attaching themselves to a receptor, these chemical signals direct a cell to do something, for example, to act in a certain way, or to divide or die. The vitamin D receptors on nerve and immune system cells mean that vitamin D is somehow affecting the cell.
When immune system cells are exposed to vitamin D in laboratory experiments, they become less inflamed. This could mean that vitamin D affects the immune system and makes it less likely to attack other cells in the body. Some researchers believe that this means vitamin D has the potential to prevent MS from developing. It could also affect relapsing remitting MS by reducing the number of relapses and how severe they are.
Most people get vitamin D from exposing their bare skin to sunlight. Some research has suggested that children who get lots of sun are less likely to develop MS as adults. So, if one grows up in a place that gets lots of sun, this individual is less likely to develop MS than someone who grows up in a place where there is little sun.
Exposing the skin to sunlight could affect the immune system in other ways apart from producing vitamin D. However, research does show that people with higher vitamin D levels are less likely to develop MS or have a relapse if they already have it.
What does the research say in general about sunlight and vitamin D and risk of multiple sclerosis?
Most of the research which shows that vitamin D may help prevent the development of MS is epidemiological.
Those with higher vitamin D levels are less likely to develop MS.In addition, higher vitamin D levels predict reduced MS activity and a slower rate of progression. Higher vitamin D levels are also associated with lower degree of disability for those with MS.
Research has found that those who get more sun exposure early and throughout life have lower chances of developing MS. Whether this is because they produce more vitamin D and that’s what helps prevent MS, or whether the sun is helping for some other reason, researchers don’t know for sure.
There is increasing evidence that solar UVB exposure is perhaps more important for reducing the risk of MS than vitamin D. If so, the epidemiological studies linking vitamin D levels to MS risk may be by association with solar UVB exposure.
It has long been known that the risk of MS increases at higher latitudes. From the relation with latitude, it appears that low solar UVB doses during winter are an important risk factor.However, low UVB exposure in summer also plays a role.
A study in Cuba found that those who spent more leisure time in outdoor activities before the age of 15 years had lower rates of MS than others.
A study in New York found that summer sun exposure but not vitamin D levels was associated with increased grey matter volume and whole brain volume.
A study conducted in Italy and Norway found that young people who spent less time in the sun in summer had an increased risk of MS.
A review of MS relapses reported that peak rates occur in spring and valley rates occur in autumn. The rate was 15% higher in spring than in autumn. The peak and valley rates have the same seasonality as vitamin D levels in the United Kingdom. Peak and valley vitamin D levels lag behind peak and valley solar UVB doses by about two months, because vitamin D levels build up slowly in summer and decline slowly in autumn.
This finding suggests that people with MS should try to receive sun exposure daily during the time that the sun is high enough in the sky that one’s shadow is shorter than one’s height. When that is not possible, artificial UVB sources might be considered.
Treating or managing MS
Whether or not taking vitamin D supplements can help people who already have MS remains unclear. The studies that have been conducted have produced conflicting results. Some research shows vitamin D can reduce the number of relapses in people with relapsing remitting MS; whereas, other research shows vitamin D has no effect on the number of relapses. This could be due to differences in study design, such as:
- the duration of the study
- the form of vitamin D, for example tablets or injections
- the amount of vitamin D
- how often people take the vitamin D, for example every day or monthly
- the people taking part in the research, for example different ethnic groups
- the way the researchers measured the effects of the vitamin D
Until now, many of the research studies looking at vitamin D have involved small numbers of people, which makes it difficult to judge if vitamin D is really having an effect or not. Further research is needed, in particularly studies that involve larger number of participants, longer durations and a comparison of placebo versus vitamin D supplements. This will help clarify whether vitamin D prevents MS or treats symptoms. Several such studies are currently underway.,
What does recent research say?
In one study, vitamin D reduced the number of brain lesions in people with relapsing remitting MS.
Only one high quality research study exists that shows vitamin D can help to treat the symptoms of MS.
A 2012 research study from Finland looked at whether or not giving vitamin D supplements to people with relapsing remitting MS improved their symptoms. The main results were:
- Taking vitamin D supplements significantly reduced the number of brain lesions found on a brain scan. A lesion on the brain means that nerve cells have been damaged or destroyed, which can lead to symptoms in the area of the body controlled by those nerves. New lesions show that there is nerve damage, which usually causes the development of more disabilities.
- The number of relapses that people had was the same whether they were taking vitamin D or not.
Most people started the study with very low amounts of vitamin D in their blood. The amount of vitamin D people took during the study was greater than the amount the US government recommends but not as much as what the Vitamin D Council recommends. All of the people who took part were also being treated for their MS by taking other medicines, so it’s difficult to know exactly what effect the vitamin D was having.
The same research team conducted a subsequent vitamin D randomized controlled trial for MS patients taking interferon-β-1b. They found that those taking vitamin D supplements had reduced number and volume of brain lesions.
However, a systematic review concluded that the evidence for treating MS with vitamin D was inconclusive.
A 2012 research study from Iran looked at whether or not taking a vitamin D supplement reduced the likelihood of developing MS in people who were at high risk of developing the condition. The main results were:
- Taking a vitamin D supplement reduced the likelihood of developing MS in people at high risk for developing the condition.
- Taking a vitamin D supplement significantly reduced the number of brain lesions detected by an MRI scan.
The people taking part in this study were taking much more vitamin D than the US government recommends. They developed significantly fewer new brain lesions than the people not taking vitamin D and were much less likely to develop MS. None of the people taking the vitamin D experienced relapses. Since the number of people in the study was so small, it’s difficult to say definitively if vitamin D plays a role in preventing MS.
Key Points from the research
- People diagnosed with MS tend to have lower blood levels of vitamin D than other healthy people of their age.
- Researchers don’t know if it’s vitamin D or some other beneficial effect of sunlight that leads to fewer people developing MS in sunny places.
- It’s not clear if vitamin D is helpful in the prevention or treatment of MS, or both. Some researchers believe that the amount of vitamin D one receives early on in the life is most important for the risk of developing MS as an adult. Once an individual has the disease, some researchers believe that taking vitamin D may not help.
- Most of the studies testing vitamin D supplements for the treatment of MS looked at small numbers of people. This makes it difficult to determine the effect of vitamin D on MS.
- Research studies have used different amounts of vitamin D. Therefore, it’s difficult to determine the most effective vitamin D dosage.
What does this mean for me?
At this time, it isn’t clear how much vitamin D one needs to prevent or treat MS, if there is any effect. If an individual has MS and wants to take vitamin D, it’s unlikely to make the symptoms worse or cause one any harm if one take less than 10,000 IU/day.
Research studies have shown that people with low levels of vitamin D in their blood may be more likely to develop MS than people with higher levels of vitamin D in their blood. People who expose their skin to the sun regularly are less likely to develop MS 6 and some researchers suggest that taking vitamin D may lower the risk of developing it. However, it isn’t clear whether getting good amounts of vitamin D, by taking supplements or by exposing the skin to the sun, could prevent one from developing MS.
Researchers don’t know whether taking vitamin D can help to reduce the number of relapses if an individual has MS.
If one has MS and wants to take vitamin D, it’s unlikely to make the symptoms worse or cause one any harm if one take less than 10,000 IU/day.
Because vitamin D improves the health of the bones and people with MS are likely to have bone disease, it may be helpful to take vitamin D. Consult with a doctor for more information.
One should not take vitamin D in the place of other medications for MS.
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This page was last updated January, 2016.