While the general population stands much to gain from a regular vitamin D supplement, sufferers of multiple sclerosis (MS) may see an even greater than normal impact on their personal health. A forthcoming study in JAMA Neurology has shown low vitamin D levels significantly predict the severity and longevity of the crippling neurological disease.

Science has known for some time that vitamin D levels correlate highly with MS severity, but the research has been limited — to this point, it has only assessed the levels in people with longstanding histories of the disease. In other words, all the studies have shown is that levels of vitamin D are connected to MS. Now, Harvard University School of Public Health (HSPH) researchers argue their study is the first to offer some proof that low vitamin D is in fact a predictor of MS.

MS is characterized by a thinning, and eventual degrading, of the insulating covers surrounding nerve cells in the brain. Each cell begins to have an increasingly harder time communicating with other cells, disrupting brain function and, ultimately, speech and movement. There is no known cause for MS; however, because MS is known to be an autoimmune disorder, experts have pegged a mix of genetics and environmental factors — such as infection — as playing a role. The Harvard researchers believe the vitamin’s anti-inflammatory properties may help preserve the outer sheath.

"Because low vitamin D levels are common and can be easily and safely increased by oral supplementation, these findings may contribute to better outcomes for many MS patients," said lead author Alberto Ascherio, professor of epidemiology and nutrition at HSPH, in a statement.

Ascherio and his team sought to better understand the role vitamin D plays in regulating the symptoms and severity of MS and the way it develops. They recruited 465 MS patients from 20 different countries who enrolled in a 2002 and 2003 study. Each subject had their vitamin D levels measured at the study’s outset and at regular intervals over a two-year period. Over the course of the entire five-year study, the team kept track of how the symptoms either improved or worsened, along with the disease in general.

Final analyses showed MS patients who maintained an adequate vitamin D level had a 57 percent lower rate of brain lesions, a 57 percent lower relapse rate, and 25 percent lower yearly increases in lesion volume than those who let their vitamin D levels drop. Participants with healthy levels of vitamin D also had lower rates of brain volume loss.

Given that roughly 2.3 million people around the world currently suffer from MS, according to the National Multiple Sclerosis Society, researchers argue the low cost and effectiveness of vitamin D supplementation should motivate doctors to pursue the method more frequently. "The benefits of vitamin D appeared to be additive to those of interferon beta-1b, a drug that is very effective in reducing MS activity,” Ascherio concluded. “The findings of our study indicate that identifying and correcting vitamin D insufficiency should become part of the standard of care for newly diagnosed MS patients.”

Source: Ascherio A, Munger K, White R. Vitamin D as an early predictor of multiple sclerosis activity and progression. JAMA Neurology. 2014.