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In her team's experiments, mice genetically engineered to
spontaneously develop the symptoms of either Crohn's disease or ulcerative
colitis were also made vitamin D deficient at birth.
The mice were
then
either maintained deficient or given vitamin D supplements in their food
to bring them up to the normal level.
The treated mice had less bowel inflammation than the untreated
mice did. In addition, the
mice that did not receive the supplements began to die at seven weeks of
age and by nine weeks more than half were dead.
In contrast none of the mice that received the supplements died
during the experiment period.
"Vitamin D deficiency is more common in people who have
inflammatory bowel disease. In addition, the anti-inflammatory drugs often used to treat
IBD can cause bone loss as a side effect," Cantorna says.
"Vitamin D taken in combination with these drugs may be able
to reduce the effective dose of anti-inflammatory needed to treat the
disease and decrease bone loss as well as treat the vitamin
deficiency."
In research she conducted previously as a postdoctoral fellow at
the University of Wisconsin, Cantorna had demonstrated a connection
between vitamin D and two other autoimmune diseases, arthritis and
multiple sclerosis. Autoimmune
diseases are disorders of the immune system in which the body attacks
itself. In arthritis, for
example, the immune system attacks the joints, in multiple sclerosis the
spinal cord and brain and in IBD, the gut.
"Since we had previously shown a connection between other
autoimmune diseases and vitamin D, it seemed reasonable to explore the
possibility of a connection in this case," she notes.
However, the Penn State researcher points out that there are other
factors that suggest that vitamin D and IBD are linked.
For example, Cantorna notes that IBD is more prevalent in North
America and
Northern
Europe, which receive less sunlight.
Vitamin D is manufactured in the skin on exposure to sunlight and
people make significantly less in northern climates, especially in the
winter. The incidence
of IBD in Canada, for example, is the highest in the world.
While Cantorna's research and IBD's geographical distribution
suggest a connection between vitamin D status and the incidence of IBD,
Cantorna cautions that vitamin D's exact role is still unclear.
She says, "It's
unclear what vitamin D does to keep the animals alive.
Is it affecting the autoimmune disease or something else?
We don't know yet how it prolongs survival."
"I think that if you are a patient who has been diagnosed with
IBD, it would be best to continue to follow your personal physician's
advice," says the College of Health and Human Development faculty
member.
"It wouldn't be a good idea to begin taking the vitamin D
pills available over-the-counter because of possible problems with
absorption. In the
experiments, we treated the mice that had full blown symptoms with an
active form of vitamin D to circumvent the absorption problems."
"However," she added, "for healthy people, it makes
sense to make sure that you are vitamin D adequate."
The project was supported with Penn State research start-up funds.
The University has begun the process of filing for patent
protection for the work.
Penn
State Science and Technology News Wire is a service of the Science,
Engineering and Research Communications Unit, Department of Public
Information. Please send your comments – mail to:VFong@psu.edu
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