Vitamin D May Protect Against MS
There is new evidence supporting the idea that vitamin D helps prevent multiple sclerosis, but it is too soon to recommend taking the vitamin to lower your risk, researchers say.
Dec. 19, 2006 -- There is new evidence supporting the idea that vitamin D
helps prevent multiple sclerosis, but it is too soon to recommend taking the
vitamin to lower your risk, researchers say.
In the first large-scale study to examine the issue, researchers from the
Harvard School of Public Health reported a strong association between vitamin D
levels within the body and MS risk among whites, but not among blacks and
The study is published in the Dec. 20 issue of The Journal of the
American Medical Association.
Senior researcher Alberto Ascherio, MD, DrPH, tells WebMD that roughly half
of white Americans and two-thirds of black Americans could be considered to
have insufficient levels of vitamin D. Because exposure to sunlight is a major
source of the vitamin for most people, vitamin D levels are usually lowest in
"Our findings suggest that vitamin D may have a direct impact on
multiple sclerosis risk," Ascherio says. "If we confirm that the
vitamin is protective, we could potentially prevent thousands of cases of MS a
year in the United States alone."
Some 350,000 new cases of multiple sclerosis are diagnosed in the U.S.
annually, and the chronic autoimmune disease is more common among women than
In earlier studies, Ascherio and Harvard colleagues reported that women who
took multivitamins with at least 400 international units (IU) of vitamin D
appeared to have a lower risk of MS than women who did not.
Their newest study involved a study population of more than 7 million
members of the U.S. Army and U.S. Navy with blood samples stored in a
Department of Defense repository.
Between 1992 and 2004, 257 people were diagnosed with MS. Each case was
compared to two people without MS matched for age, race, sex, and dates of
MS Risk and Racial Groups
Because dark-skinned people do not make vitamin D through the skin as easily
as light-skinned people, separate analyses were conducted among whites, blacks,
and Hispanics. UV rays from the sun allow vitamin D to be made in the skin.
The investigation revealed that among whites, people with the highest
circulating vitamin D levels had the lowest MS risk. Compared with whites with
the lowest levels, those with the highest were found to have a 62% lower risk
for developing the disease.
The strongest association was seen among the youngest study
Vitamin D and the Immune System
Ascherio says the findings add to the mounting evidence supporting a role
for vitamin D in regulating the immune system and suppressing autoimmune
Earlier research from the Harvard team suggested a protective role for
vitamin D against rheumatoid
arthritis, another autoimmune disease.
Other researchers have reported that vitamin D deficiency may increase the
risk of a wide range of medical maladies, including heart
disease, diabetes, unexplained
muscle and joint pain, and certain cancers.