D may slow the progression of multiple
sclerosis (MS) and also reduce harmful brain activity, a new study
Correcting vitamin D deficiency early in the course of the disease is
important, according to the report, published online in JAMA
Read: Why vitamin D is your key to optimal health
But some experts say it's too soon to recommend giving vitamin D supplements
to people with the central nervous system disorder.
"No one knows what the connection between MS and vitamin D is,"
said Nicholas LaRocca, vice president for health care delivery and policy
research at the National Multiple Sclerosis Society. "What they suspect is
that vitamin D has some effect on the immune system."
Also, what dose of the vitamin might be appropriate isn't clear, he said.
"We don't know what a good level would be. There is no scientific
consensus on a treatment protocol. We may get to that point eventually,"
However, the lead researcher of the study, Dr Alberto Ascherio, a professor
of epidemiology and nutrition at the Harvard School of Public Health, is
convinced that vitamin D often called the "sunshine vitamin" – can
be a real benefit to MS patients.
"These findings, combined with previous evidence that vitamin D
deficiency is a risk factor for MS, and [research on] the immunological effects
of vitamin D strongly suggest that maintaining an adequate vitamin D status is
important in the treatment of MS," he said.
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Vitamin D supplementation
In the study, vitamin D levels at the time of the first MS symptoms
predicted the progression of the disease over the following five years,
People with lower vitamin D levels – below 50 nanomoles per liter (nmol/L) – were more likely to develop new brain lesions and had a worse prognosis than
those with higher levels, Ascherio said. "Individuals who present with
symptoms suggesting MS should be screened for possible vitamin D deficiency,
and this should be corrected by vitamin D supplementation," he said.
MS is a chronic, debilitating disease. In many cases, symptoms are mild, but
sometimes people with MS become unable to walk, write or speak.
Dr Emmanuelle Waubant, director of the Regional Paediatric MS Centre at the
University of California, San Francisco, is among those urging caution
regarding vitamin D supplementation.
"Although these data are exciting, these are just studies of
association," Waubant said. "We still need to do a randomised
clinical trial of vitamin D supplementation to confirm that supplementation
improved MS outcomes."
Another expert agreed.
"The results are exciting because they confirm our own prior
work," said Dr Ellen Mowry, an assistant professor of neurology at Johns
Hopkins University School of Medicine in Baltimore.
However, she added that no study has yet established whether taking vitamin
D supplements helps reduce new symptoms and disability from occurring in people
with MS. "It's possible that the effects we have seen in this and the
prior studies are actually due to something else, and not to vitamin D
insufficiency," she said.Safety and effectiveness
Also, even though vitamin D is sold over the counter, it doesn't necessarily
mean it's safe to take a lot. "Like any medication, it may have negative
effects of which we are not aware," Mowry added.
Vitamin D is also obtained from sunlight and through certain foods, such as
fatty fish and fortified dairy products.
Mowry and Waubant are heading up a large clinical trial of vitamin D in MS
patients. Similar trials are underway in Europe and Australia, Waubant noted.
"It is my belief that these trials will help answer the important
question of whether it is safe and effective to recommend high-dose vitamin D
supplementation to people with MS," Mowry said.
For the study, researchers measured vitamin D levels in 465 patients with
signs of MS who took part in a trial designed to study interferon beta-1b
treatment. For the next five years, patients underwent MRI scans so the
researchers could track brain
lesions associated with the disease.
During the first year of follow-up, increases of 50 nmol/L of vitamin D were
associated with a 57% lower risk of developing new brain lesions, the study
In addition, patients had a 57% lower risk of relapse, the researchers
found. They also had a 25% lower yearly increase in T2 lesion size (these
hallmarks of MS appear as bright spots on an MRI) and a 0.41% lower yearly loss
in brain size over the course of the study.
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