Vitamin D linked to MS again

sun..but is it ’cause-and-effect’?

Multiple Sclerosis (MS) is a poorly understood disease of the central nervous system.  The immune system attacks  and damages nerves.  Over time, nerve signaling deteriorates, causing a multitude of symptoms, ranging from fatigue to vision problems to seizures.  People can lose control of muscles and body functions, but the severity and occurrence of symptoms varies from one person to another.

The causes of MS are not known.  Genetics likely contributes to risk.  And researchers have recognized that MS seems to be more prevalent in areas far from the equator.  That fact suggested a possible link to sunshine, which led researchers to investigate any connection between vitamin D status and MS.  People living closer to the equator have higher blood vitamin D, thanks to more intense sun light, which stimulates vitamin D production in skin.

Could this vitamin be protective against MS?  Studies are looking at this, but data collection will take time.  Meanwhile another study just out hints that the vitamin D link is tied to genes.  The $64 question: does this data mean that taking vitamin D and boosting blood levels would actually prevent MS?

The study was done in two parts.  First, using over 30,000 subjects, the researchers identified 4 genetic variations that affect the vitamin D level associated with sun light.  Once they established the effects of each of these 4 gene variations on vitamin D status, they compared risk of developing MS with presence of these genetic variations.  Result: genetically lower vitamin D levels were strongly associated with risk for developing MS.

So take vitamin D and prevent MS?

Not so fast.  First, this study only found a link between vitamin D and MS.  It did not find causation.  It’s possible that some other factor common to vitamin D gene variations and MS is the true culprit.  Low vitamin D could just be a symptom of some other MS-causing process.  Or it might just be one piece of a complex metabolic puzzle.  A connection between vitamin D and the immune dysfunction that leads to MS isn’t established either.

Research to clarify any direct impact of vitamin D would involve following susceptible individuals for years, supplementing them with vitamin D, measuring blood levels and assessing symptoms.  Some research is ongoing, but so far we do not know if raising blood vitamin D levels will prevent MS, alleviate existing symptoms or even cure it.  Nevertheless, the National MS Society has funded several vitamin D studies, so clearly some MS experts believe there might be a connection.

If you have MS, or feel you are at increased risk because other family members have had it, don’t just start loading up on vitamin D supplements.  You should first have your blood level tested.  Your doctor can advise on whether you’re deficient.  Taking extra D if you aren’t deficient isn’t a good idea.

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