A lack of vitamin D may be a direct cause of multiple sclerosis (MS), a study has found. Researchers say the discovery may have important public health implications since so many people have insufficient levels of the essential vitamin.
The findings may help explain why rates of MS, a potentially disabling auto-immune disease that damages nerve fibres, are higher in high-latitude regions such as northern Europe, which have fewer sunny days. Sunshine triggering a chemical reaction in the skin is the primary source of vitamin D.
Previous studies have suggested an association between lower vitamin D levels and a higher risk of MS. But now scientists have demonstrated a genetic correlation that points strongly to a causal link.
Scientists who scoured the DNA of 33,996 participants identified four single-letter variants in the genetic code that were closely associated with a vitamin D blood marker.
A comparison between thousands of MS sufferers and healthy individuals found that people whose genetic makeup was associated with a lack of vitamin D – meaning they had fewer of the biomarker variants – were at least twice as likely to have MS.
Writing in the online journal Public Library of Science Medicine, the authors, led by Dr Brent Richards from McGill University in Canada, wrote: “The identification of vitamin D as a causal susceptibility factor for MS may have important public health implications, since vitamin D insufficiency is common, and vitamin D supplementation is both relatively safe and cost-effective.
“The importance of these findings may be magnified in high-latitude countries, which have disproportionately higher rates of MS and also higher rates of vitamin D insufficiency.”
The research showed that every standard deviation decrease in genetic variants linked to the vitamin D biomarker doubled the risk of MS. Standard deviation is a statistical measurement of variation from an average.
The finding provided “strong evidence in support of a causal role of vitamin D in MS susceptibility”, said the scientists.
They added: “Whether vitamin D sufficiency can delay or prevent multiple sclerosis onset merits further investigation in long-term randomised controlled trials.”
Vitamin D generated by sunlight is converted in the body into the blood marker 25-hydroxyvitamin D (25OHD). This is then further converted into the active form of the vitamin, calcitriol, which acts as a powerful hormone. 25OHD levels in the blood are considered the best indicator of a person’s clinical vitamin D status.
MS, which affects about 100,000 people in the UK, occurs when the immune system attacks the protective myelin sheath that surrounds nerve fibres and acts as an insulator. Nerve signals are disrupted, leading to symptoms that can range from mild tingling sensations to full-blown paralysis. In rare cases that progress rapidly, the disease can be fatal.
Dr Benjamin Jacobs, from the Royal National Orthopaedic hospital in London, said: “This study reveals important new evidence of a link between vitamin D deficiency and multiple sclerosis. The results show that if a baby is born with genes associated with vitamin D deficiency they are twice as likely as other babies to develop MS as an adult. This could be because vitamin D deficiency causes MS, or possibly because there are other complex genetic interactions.”
Prof Danny Altmann, an immunologist from Imperial College London, said: “Vitamin D is relatively cheap, safe and many of us would be all the healthier if we could achieve the serum levels that our ancient ancestors presumably acquired when roaming outdoors in temperate climates, unclothed and eating a diverse diet including oily fish.
“While it may be too much to expect therapeutic vitamin D to treat or reverse ongoing MS, this paper will add to the weight of argument for routine vitamin D supplementation of foodstuffs as a broad preventative public health measure.”
Dr Susan Kohlhaas, the head of biomedical research at the MS Society, said: “More than 100,000 people are affected by multiple sclerosis in the UK, so the potential link between vitamin D and the risk of developing MS is an incredibly crucial area of research.
“There are many unanswered questions around what causes MS so this large-scale study is an exciting step towards understanding more about the complex nature of the genetic and environmental factors that contribute to it.
“There are government guidelines around how much vitamin D people should take, and taking too much can lead to side-effects, so we’d encourage people to talk to their health professional if they’re thinking of doing this. We’d also welcome more research into this area, as we know it’s really important to people living with MS.”
Source: The Guardian © 2015 Guardian News and Media Limited (26/08/15)
Researchers have conducted a survey of over 2,000 adults with multiple sclerosis to determine whether vitamin D supplementation, latitude and/or sun exposure are related to the relapse rate and disease progression of multiple sclerosis (MS).
Clinical trials have recently suggested vitamin D supplementation has a positive effect on MS. However, the dosage that provides the most benefits remains unclear. Thus, researchers recently assessed the relationship between different doses of vitamin D and health outcomes of MS. In addition, the researchers looked at latitude and sun exposure.
The researchers surveyed 2,301 participates with MS online. The average age was 45. The survey consisted of 163 questions inquiring about socio-demographics, MS diagnosis, level of disability, health related quality of life and symptom severity. They also asked specific questions regarding vitamin D supplementation dosage and sun exposure habits. The researchers found:
• A total of 1,504 (63 per cent) of participants reported they intentionally received sun exposure to increase their vitamin D status.
• The majority of participants took vitamin D supplements (81.8 per cent) with an average supplementation regimen between 2000 and 5000 IU daily.
• Deliberate sun exposure and latitude was strongly associated with health related quality of life. Although this relationship disappeared after adjusting for confounding factors.
• Vitamin D supplementation and health related quality of life were significantly related before and after adjusting for confounding factors with a dose-response effect.
• An increase of latitude by one degree (further from the equator) was associated with a two per cent increase in odds of moderate disability and a three per cent increase in odds of high disability compared to those with no disability or mild disability.
• Relapse rate was also related to latitude. An increase of latitude by one degree was associated with a one per cent increase in odds of having more relapses over the previous year.
• Those taking vitamin D supplements had about a one third lower annualised relapse rate compared to those who did not.
The researchers concluded: “We detected significant associations between latitude, deliberate sun exposure and vitamin D supplementation and health outcomes of this large group of people with MS.
“Vitamin D is likely to have a pivotal role in these associations; its role in MS health outcomes urgently requires detailed exploration with well-designed clinical trials.”
These findings provide further support to the extensive research that has found vitamin D plays a role in multiple sclerosis. The high percentage of MS patients who take vitamin D illustrates that MS patients have become aware of the benefits of vitamin D.
There are a few limitations to keep in mind in regards to this study. All measures were self-reported, leaving room for recall bias. Also, vitamin D status was not measured. Lastly, the study is cross-sectional, meaning that we cannot conclude causation.
Source: Vitamin D Council © Vitamin D Council 2015 (13/08/15)
Britons do not get enough sunlight leading to deficiencies of vitamin D and a host of related illnesses, research claims.
The vitamin – linked by some with combating cancer, multiple sclerosis, asthma and Type 2 diabetes – is formed naturally in the skin when it is exposed to sunlight.
Now for the first time government health advisers are expected to recommend that everyone should increase their daily intake of vitamin D with supplements because gloomy winters fail to provide enough sunshine to maintain healthy levels throughout the year.
Britons need to top up on their vitamin D artificially, according to a draft report published by the Scientific Advisory Committee on Nutrition (SACN). Until now, it was assumed that exposure to sunlight would enable most people to reach this target – but new scientific evidence suggests that is not the case in UK.
Links have also been drawn between vitamin D and the prevention of cancer, multiple sclerosis, asthma, and Type 2 diabetes – though these remain inconclusive. The report suggests people between 11 and 64 should ensure they have 10 micrograms of vitamin D every day.
But the report estimates that most people get only five micrograms from their diets. Dr Adrian Martineau, an expert on vitamin D at Barts and the London School of Medicine and Dentistry, said that a daily intake of 10 micrograms would “significantly improve public health in the UK”.
And he stressed that the latest advice marked a “sea change” in thinking. He said: “Before this the assumption was that adults were able to make all the vitamin D they needed from sunshine, and didn’t need to have any dietary or supplementary intake.
“The action of sunlight on the skin in the UK is highly variable depending on the time of year and the latitude – you’ll get more UVB [ultraviolet] in Brighton than in John O’Groats – and how much skin is exposed and the colour of skin.”
Nutrition experts said that most diets were not likely to provide the recommended 10 micrograms of vitamin D every day either. Helena Gibson-Moore, a scientist at the British Nutrition Foundation, said: “Given current intake levels of vitamin D from foods at less than five micrograms per day, the draft recommendation of 10 micrograms is unlikely to be achievable from these foods alone.”
She added: “Taking some exercise in the sunshine is sound advice for all.”
Professor Hilary Powers, chair of the SACN vitamin D working group, said: “It is important to remember that this vitamin D report is a draft so the recommendations may change after the consultation period.
“SACN will be publishing its final recommendations in early 2016.”
Source: Daily Express Copyright ©2015 Northern and Shell Media Publications (03/08/15)
Study suggests benefits of vitamin D(23/06/15)
A team of researchers from the Isfahan University of Medical Sciences in Iran, led by Dr Masoud Etemadifar, have conducted a randomised controlled clinical study in 15 pregnant women with low vitamin D levels and multiple sclerosis.
Women treated with 50,000 IU/week (International Units) of vitamin D3 showed significantly higher vitamin D levels and fewer symptoms related to MS six months after delivery of their babies, as measured by the expanded disability status scale.
Although not statistically significant, the relapse number among the study participants also appeared to be lower in women supplemented with vitamin D.
The study did have limitations in that it was only exploratory in nature and featured a small sample size.
However, the findings revealed that, compared to routine care, the supplementation of pregnant women with MS with standard high-dose supplementation of vitamin D had a significantly positive effect on the disease.
These results are promising and warrant the need for further studies with larger sample sizes and longer follow-ups to ascertain the true safety and efficacy of supplementation in this subgroup of patients.
Source: Multiple Sclerosis News Today © BioNews Services 2015 (23/06/15)