Multiple sclerosis is a debilitating disease that affects the communicative capability of the central nervous system. Though its causes are not clear, low levels of vitamin D in the blood have been tied to an increased risk of developing the condition. Furthermore, those with MS and low levels of vitamin D are more likely to have greater disability and more disease activity. A breakthrough may now have arrived in a new study by the American Academy of Neurology, which suggests that taking high doses of vitamin D3 is safe for people with multiple sclerosis and may correct the body's hyperactive immune response.
In healthy people, the neurons in the brain — the core of the central nervous system — conduct the signals that control the body's many physical and mental functions. MS causes these links to become damaged and so compromises their functionality — the results can range from tingling in the limbs to blindness and paralysis. It's thought that, for reasons not fully understood, the neuron pathways are damaged by the body's own immune system.
For the study — which was published in the online journal Neurology — 40 people with relapsing-remitting MS were treated with doses of either 10,400 IU (about 260 micrograms) or 800 IU (about 20 micrograms) of vitamin D3 each day for six months. This is slight to significant increase on the recommended daily allowance of vitamin D3 of 600 IU (around 15 micrograms).
Blood tests were taken at the start of the study and then again after three and six months to measure the amount of vitamin D in the blood and the response by the immune system's T cells. T cells are lymphocytes — small while blood cells which play a key role in the immune response and so in MS. Side effects from the vitamin supplements were minor and were no different between participants taking high or low doses. Only one person in each group had a relapse of disease activity.
The important difference, the researchers found, was that people taking the high dose of the vitamin had a small but significant reduction in the number of T cells related to MS activity whereas the people taking the low dose experienced no change. When the increase in vitamin D in the blood was greater than 18 nanograms per milliliter (ng/ml), every 5 ng/ml increase in vitamin D led to a 1% decrease of the specific T cells in the blood responsible for damage to the nervous system.
This is encouraging news — if scientists can strike right balance, it's possible the symptoms of MS can be mitigated. While researchers are still determining the optimal level of vitamin D in the blood for people with MS, it's thought the higher dose of vitamin D in the study could be a target for people with MS. Though vitamin D levels above 30 ng/ml are considered sufficient for the generally healthy, researchers say that, for people with MS, levels above 50 ng/ml could be necessary to reduce disease activity.
"These results are exciting." says study author Peter A. Calabresi, of Johns Hopkins University School of Medicine in Baltimore, MD, and a Fellow of the American Academy of Neurology. "Vitamin D has the potential to be an inexpensive, safe and convenient treatment for people with MS. More research is needed to confirm these findings with larger groups of people and to help us understand the mechanisms for these effects, but the results are promising."