Low Vitamin D Levels May Worsen Multiple Sclerosis Symptoms
Vitamin D deficiency has been studied extensively for its role in multiple sclerosis, a disease which affects 2.5 million people worldwide. A new study from Johns Hopkins University School of Medicine finds that those multiple sclerosis patients with low levels of vitamin D have an increased number of brain lesions and signs of more active disease.
Multiple Sclerosis is an autoimmune disease in which the body’s immune system attacks the coating of nerve fibers in the brain and spinal cord. The coating, made of a fatty protein called myelin, insulates the nerves and helps them send the electrical signals through the nerves that control movement, speech and other function.
Ellen M. Mowry MD MCR, an assistant professor of neurology formerly with the University of California San Francisco, evaluated data from a five-year study of 469 people with MS. Each year, patients had blood drawn and MRI’s performed. Areas of inflammation show up on an MRI as lesions that look like white spots.
Each 10 nanograms-per-milliliter (ng/mL) increase in blood vitamin D levels was associated with a 15% lower risk of new lesions and a 32% lower risk of spots of active disease, which would require treatment to reduce the likelihood of permanent nerve damage. Higher vitamin D levels were also associated with lower long-term disability as measured by the Expanded Disability Status Scale (EDSS).
Blood levels below 20 ng/mL are considered inadequate for bone and overall health in healthy individuals.
Previous studies have indicated that lower vitamin D levels are associated with increased relapse risk in certain MS patients. The most common form of MS is called relapsing-remitting MS, where the patients at times have no symptoms, but at other times suffer from attacks such as blurred vision, numbness and weakness. Some patients with relapsing-remitting MS progress to a more serious form of the disease due to damage of the nerve cells.
Dr. Mowry, though, warns that there still is not enough evidence to support large doses of vitamin D in patients. “Even though lower levels of vitamin D are associated with more inflammation and lesions in the brain, there is no evidence that taking vitamin D supplements will prevent those symptoms,” she says “If we are able to prove that through our currently-enrolling trial, it will change the way people with multiple sclerosis are treated.”
“People with MS should talk with their doctors about the pros and cons of taking vitamin D before starting the supplement,” Dr. Mowry stresses to patients. The recommended daily intake for vitamin D from dietary sources for healthy adults is between 600 and 800 IU.
Ellen M. Mowry MD MCR et al. Vitamin D status predicts new brain magnetic resonance imaging activity in multiple sclerosis. Annals of Neurology, Volume 72, Issue 2, pages 234–240, August 2012. DOI: 10.1002/ana.23591
Office of Dietary Supplements (National Institutes of Health)