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Page last updated:06-Mar-2014

Sunlight & Vitamin D

The MS vitamin D connection is at last being taken seriously in mainstream medicine. There is a striking geographical variation in the incidence of MS from country to country. This is in part related to saturated fat consumption, and the ratio of polyunsaturated fats to saturated fats, but also relates to another independent variable, latitude.1  Esparza and co-workers listed countries in order of mortality rates from MS and compared this with latitude, that is distance from the equator. With a few exceptions, the exceptions being where fish consumption is very high, it was very nearly a direct correlation. This has also been shown within countries.2,3

The Vitamin D Theory

The vitamin D MS theory was first proposed by Goldberg in 1974.4 He felt that getting insufficient sunlight to form vitamin D could be the trigger for MS in genetically susceptible people. He calculated, in relation to vitamin D and MS, on the basis of amount of sunshine in areas with little MS, and the rate at which vitamin D is formed in the body, that it would take 3 800 international units of vitamin D daily to prevent the onset of MS. Incredibly, exactly this dose has recently been calculated to be the amount of vitamin D required to maintain a steady reasonable vitamin D level.5

The vitamin D and MS theory has now been revisited and refined.6 Vitamin D is formed in the body from the action of sunlight on the skin. Ultraviolet light consists of ultraviolet A, B and C wavelengths. UVB acts on a chemical in the skin, one of the by-products of cholesterol metabolism, to form other chemicals which then become vitamin D. Vitamin D is intimately involved in the normal growth and development of bone, and in the absorption of calcium from food and its deposition in bone.

Vitamin D also has profound effects on the immune system. Vitamin D functions in the body by attaching to a specific receptor in cells. Receptors can be thought of as the locks into which a particular key, in this case vitamin D, fits. These receptors are present on the white blood cells involved in the immune response in MS. So vitamin D plays a part in regulating the immune system. A number of animal experiments have shown that the animal model of MS is either stopped from developing or progressing by giving vitamin D supplements or by UV light therapy.7,8

Vitamin D is intimately involved not only in immune system function, but also brain function.9 It appears that vitamin D has protective effects and immunomodulatory effects in the brain, and is useful in neurodegenerative and neuroimmune diseases, typified by MS. Researchers have concluded that for vitamin D and multiple sclerosis, its immunomodulatory potency is equivalent to other currently used immunosuppressants yet without their typical sometimes severe side effects.10
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Goldberg’s Study on Vitamin D Supplementation

In 1986, Goldberg performed a MS and vitamin D study, supplementing vitamin D in MS patients.11 The numbers in this study were very small. Only sixteen patients were entered into the study. There was no control group, and Goldberg compared the patients’ relapse rates after supplementation with those before. Goldberg gave patients 5 000 units of vitamin D per day. He did this by giving 20g of cod liver oil a day. He also gave large doses of calcium and magnesium. There were 2.7 times as many relapses per year before the supplements than after, with a p value of <0.005. A number of the patients dropped out of the study, and the numbers were small. Nonetheless, none of the patients who stayed on the supplements for the study period failed to have a lower rate of relapsing than before the supplements.
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Embry’s Study on Vitamin D Levels

Embry and colleagues have also undertaken a multiple sclerosis and vitamin D study, comparing monthly vitamin D blood levels in 415 patients from a particular area in Germany with the number of lesions detected on MRI scanning in MS patients from the same area.12 High levels of vitamin D correlated closely with low levels of disease activity and vice versa. The authors recommended that doctors treat their patients with year-round supplements of 3 000-4 000 U per day of vitamin D. It would not surprise if the effect of sunlight was more marked than interferon or glatiramer. Embry’s paper seemed to suggest a roughly 50-70% reduction in the number of MS lesions when UV exposure was at its maximum in summer compared to mid-winter, so we may see that sort of level of benefit for people getting regular sunlight. And this effect size may be even higher as maximal vitamin D levels were not particularly high in this study.
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Other Studies

A 2005 MS and vitamin D study from Finland measured vitamin D levels during relapses and compared these with levels during remission.13 They found the levels to be lower during a relapse and concluded that vitamin D may be involved in the regulation of disease activity in MS. Although levels were lower during relapses, they were mostly still in the ‘normal’ range. It seems likely that just having a normal vitamin D level may not be enough to significantly reduce the risk of relapses; a ‘high’ level may be more protective.

A vitamin D and MS study from Turkey showed that people with MS had significantly lower levels of vitamin D than people without MS.14 61% of MS patients had low vitamin D levels, and many had osteoporosis, and muscle pain due to the low vitamin D levels. A US study of MS patients in a long term care facility showed high levels of osteoporosis, suggesting vitamin D deficiency.15 So, in relation to MS and vitamin D, many authorities now recommend that people with MS get adequate vitamin D both to control the illness itself, but also to minimize the risk of complications like falls and fractures.16 Additionally, MS and vitamin D research from the US Nurses Health Study showed that vitamin D supplementation reduced the risk of developing MS by 40%, and this was with very low dose supplementation.17

A further vitamin D and MS study by US researchers examined stored blood of over 7 million army recruits from 1992-2004 and compared the vitamin D levels with their risk of developing MS.18 They found 257 new cases of MS in the group. There was a significant decrease in risk with increasing vitamin D levels among whites, but not blacks or Hispanics, who had lower vitamin D levels than whites. Levels of around 100nmol/L or more seemed to be protective, with almost a two thirds reduction in risk for those with these higher levels.

In a small Canadian MS and vitamin D study presented to the American Academy of Neurology meeting in 2009, patients were given increasing doses of vitamin D to determine its safety at high dose. Apart from finding that high doses were safe (the higher dose group averaged 14,000IU per day through the study versus 1,000IU for the group treated with standard doses by their doctors), the researchers found that the higher dose group had 2/3 fewer relapses through the course of the study. Further, measures of immune activity showed a shift in balance away from an inflammatory profile. This is very important data about multiple sclerosis and vitamin D. The magnitude of the benefit derived from taking vitamin D supplements at high dose was roughly twice as big as the effect of taking disease-modifying drugs like the interferons; and this was in comparison to taking a conventional dose of vitamin D. Had it been compared to taking placebo, the effect would almost certainly have been even bigger. This is compelling evidence that vitamin D supplements should be routinely prescribed for people with MS, and at a substantial dose.
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Epidemiological Evidence about Sun Exposure and MS

Freedman and co-workers looked at the effects of sunlight on MS using the death rate from MS in 24 states of the USA over the period 1984-1995.19 MS patients were matched against control patients of the same age dying of other diseases, and results were analysed allowing for age, sex, race, and socioeconomic status. The more sunlight people were exposed to in the course of their work, the less likely they were to die from MS. People with high occupational exposure to sunlight who also had high exposure out of work had the lowest death rates by far, with an odds ratio of only 0.24, that is they were only 24% as likely to die from MS as those with low sun exposure. Another study from Oxford University on a very large database of people in the UK found that people with MS were only half as likely to get skin cancer.20 They had similar rates of all other cancers, so it seemed likely that sun was affording some protection against MS, in that people getting more skin cancer due to their sun exposure were much less likely to get MS.
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Australian Data

A study from Tasmania looked at the rates of MS and malignant melanoma in each of the major cities of the states of Australia and compared them with the amount of sunlight in the area. This study showed that the correlation between low ultraviolet radiation and MS was considerably stronger than that between high UV and melanoma.21 Good experimental work from Tasmania has shown that adequate sun exposure, particularly in winter, between the ages of 6 to 15 especially, reduced the risk of developing MS in later life by about two thirds.22
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How Much Sun Is Enough?

A review of vitamin D production from sunlight recommended getting all over sun (such as swimming in a pair of bathers) for about 10-15 minutes on a standard UV index of 7 day.23 If the UV index is 14, you need half the time for the same amount of vitamin D. The UV index anywhere in Australia can be checked at, the Bureau of Meterology website, and there are similar sites in all countries. The UV index varies throughout the day, being highest at midday and tailing off on both sides of this time. If the UV index of the day is listed as 14 on the Bureau website, that means 14 at midday; at 10am and 2pm it will be around half this, so it is better to get your sun at these times in summer when the UV index can be that high. If the UV index is listed as 3, then it is ideal to get sun exposure around midday to maximise the amount; but you will need to stay out twice as long as recommended, given the index is so low. The right dose of sun exposure is just short of getting some colour in the skin on each occasion, and 2-3 times a week is probably enough. This amount of whole body sun exposure generates the maximum amount of vitamin D possible, that is about 10,000 to 15,000 international units (IU). Staying longer in the sun doesn’t cause any more vitamin D to be made, and is a bad idea in that it raises the risk of other diseases, particularly skin cancer. Exposing a smaller area of the body for a longer period doesn’t work either as once all the vitamin D is made in a given area of skin (in the 15 minutes or so), no more is made until the chemical in the skin is formed again, roughly by the next day. This amount of sun exposure is very safe.

UVB produces vitamin D when it hits the skin. All UV light gets through water, so swimming doesn’t reduce the amount of vitamin D produced. However, ordinary glass absorbs UVB while letting the UVA through, so you can’t get vitamin D by sitting inside and getting the sun through a glass window. Most solariums have a mixture of UVA and UVB but it is advisable to check with the solarium that this is the case before using or buying a sun-bed to get adequate vitamin D on cloudy days.
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Vitamin D supplements

Vitamin D levels in the body can be easily measured with a simple blood test. Until fairly recently, a level of less than 25nmol/L was considered to represent moderate to severe deficiency and a level of 25-50nmol/L mild deficiency. Many laboratories have now changed their recommended normal levels to 75-250nmol/L reflecting recent research indicating a higher upper level of normal is quite safe. So, currently <75nmol/L is considered insufficient, and <50nmol/L deficient. In the USA, the measure is ng/mL, with 100nmol/L equivalent to 40ng/mL. So if you have your reading in the US in ng/mL, multiply by 2.5 to get the nmol/L we discuss on this site; so if your reading is 50ng/mL in the US, then multiply by 2.5 and your reading will be 125nmol/L for Australia, New Zealand and elsewhere. If you have your reading in nmol/L and want to convert to the US units of ng/mL, divide by 2.5; so if your reading in New Zealand is 150nmol/L, divide by 2.5 and the US reading will be 60ng/mL.

There is evidence that optimal levels in general are really quite a bit higher24
, and almost certainly so for vitamin D and MS. The recommended daily allowance of vitamin D in Australia is 200IU. This amount of vitamin D is way too low. It is based on the amount required to prevent rickets. It is equivalent to the amount of vitamin D your skin would make in 6 seconds of all over sun in Perth on a summer’s day. Vieth and others have shown that in sunny countries the vitamin D levels are at least 100-140nmol/L, and more like 135-225nmol/L, and that a level of 200nmol/L may actually be optimal.25 Others have suggested a level as high as 250nmol/L may be optimal.26 To achieve a level of 100nmol/L requires daily intake of about 4 000IU of vitamin D for people who are not getting any sun. To get to 140nmol/L needs about 10 000IU a day in the absence of sunlight. It has been shown that average healthy men’s bodies use about 3 000 to 5 000IU a day.5

It is not possible to get toxicity from vitamin D if it all comes from the sun. Only supplements can potentially produce toxic levels. The only published toxicity however is from supplements of 40 000IU a day.23

The right form of vitamin D to take is vitamin D3 or cholecalciferol. This is the natural form that is made in the body in response to sunlight. In Australia, because it is such a sunny country, regulators have not in the past allowed vitamin D to be sold. Until recently, the only form available in Australia was vitamin D2 or ergocalciferol. This is synthetic, available on prescription only, and is not the optimal form to take. It is also expensive. Vitamin D3 on the other hand is cheap. The easiest way to obtain supplies at a reasonable strength is over the internet. A good supplier of D3 at 5,000IU per capsule is in pounds sterling or in American dollars. Another good product is vitamin D3 at 50,000IU per capsule, obtainable at for USD43 for 100 capsules. Taking one every 10 days is the equivalent of 5,000IU a day, and is great for taking one-off megadoses for people just starting or if vitamin D levels in blood get low.

My recommendation regarding multiple sclerosis and vitamin D is that when first diagnosed with MS, people should ask for a vitamin D level immediately. It is very common for this first level to be low, and often this is why the attack happened. Australian researchers are now calling for ‘Active detection of vitamin D insufficiency among people with MS and intervention to restore vitamin D status to adequate levels … as part of the clinical management of MS’.27 Many neurologists I know are now doing this routinely at diagnosis. If the level is very low, it can be brought up very quickly with a one-off megadose of vitamin D followed by regular capsules.28 Many people get quite nervous about using large doses of vitamin D for MS, but the research shows that it is very safe, and indeed necessary if levels are to be raised quickly.

For people with initial levels indicating severe deficiency less than 12.5nmol/L a one-off megadose of 600,000IU raised levels to an average of 73nmol/L. This is still probably half the level which may be optimal in MS, but it can be seen that even large doses of this vitamin are quite safe. More recent research has shown that people who are overweight or obese require even larger doses of supplements to get levels up.29 My suggestion is to get a one-off dose like this if the initial level is low, and then take a regular supplement of around 5,000IU a day in winter, or more if required (10,000IU a day is perfectly safe), and the same on summer days when you get no sun, to get the level to around 150nmol/L as a minimum. The level should be checked at the end of each winter of supplementation to make sure it is not being overdone. Holick, a world authority on vitamin D suggests annually checking one’s vitamin D level as a routine.30
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Many experts, on the basis of epidemiological data showing less MS where there is more sun, animal work on improving experimental auto-immune encephalomyelitis with light therapy, reduced risk of MS with adequate sunlight or vitamin D supplementation and limited human studies, believe that sunlight improves MS. The evidence is convincing. People with MS can feel comfortable that sunlight is likely to improve their outcome from the disease, and protect them from many others in addition. Provided the amount of UV radiation is not excessive, this is a very safe therapy. In winter, in most places in the world, a vitamin D supplement is necessary to keep vitamin D levels optimal at above150nmol/L (60ng/mL for those in the US). Regarding vitamin D and multiple sclerosis, research suggests strongly that high-normal levels are required, so some people with MS aim even higher, perhaps at 200nmol/L. In my view, this will soon become accepted medical practice in the treatment of MS. The medical community is rapidly coming to an acceptance of the importance of adequate vitamin D levels for good health.
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