D May Help Prevent
MS, Rheumatoid Arthritis
Vitamin D -- which the body makes when
exposed to sunlight -- may help prevent multiple sclerosis and
rheumatoid arthritis, two studies suggest.
The findings may help explain why
the two autoimmune diseases are more common in northern climes,
where sunlight is often scarce, the researchers said.
In a study released Monday for
the Jan. 13 issue of Neurology, the researchers found women who
take multivitamins containing vitamin D are 40 percent less likely
to develop multiple sclerosis than women who do not take supplements.
"Because the number of cases of
MS increases the farther you get from the equator, one hypothesis
has been that sunlight exposure and high levels of vitamin D may
reduce the risk of MS," said Kassandra Munger of the Harvard School
of Public Health in Boston, who led the study.
"These results need to be confirmed
with additional research, but it's exciting to think that something
as simple as taking a multivitamin could reduce your risk of developing
Multiple sclerosis is a crippling
disease caused when the immune system, for unknown reasons, mistakenly
damages the myelin, the protective fatty sheath around nerves.
Symptoms range from tremors to
paralysis to memory loss and vary from person to person. There
are treatments that help, but no cure.
Munger's team looked at two studies
of 187,000 nurses that followed what the women eat and do in their
lives, then chronicled their health. Out of all the women, 173
developed MS over a 20-year period.
The nurses with the highest intake
of vitamin D from supplements -- 400 IU or more a day -- were
40 percent less likely to develop MS than those who used no supplements.
The women who only got vitamin D from food such as fortified milk
did not lower their risk of MS.
A second study, published in the
journal Arthritis & Rheumatism, showed that vitamin D may prevent
rheumatoid arthritis, another autoimmune disease in which the
joints are attacked and destroyed.
The 11-year study of 29,368 women
aged 55 to 69 involved detailed questions about eating habits,
use of vitamin pills and other lifestyle choices. In this group,
152 women developed rheumatoid arthritis.
The women whose diets were highest
in vitamin D had the lowest occurrence of the disease, the researchers
at the University of Iowa, the University of Alabama at Birmingham
and elsewhere found. Again, supplements seemed to be a better
source than food, they reported.
The vitamin may somehow affect
the immune system, the researchers said.
Reference Source 89