Research with mice at Penn State has demonstrated a connection between vitamin D deficiency and two bowel diseases that occur in one out of every 1,000 people in North America and Europe.
Dr. Margherita T. Cantorna, assistant professor of nutrition and director of the research project, says "Our experiments show that vitamin D deficiency worsens the symptoms of Chron's disease and ulcerative colitis. Treatment with Vitamin D for as little as two weeks lessens the symptoms of these inflammatory bowel diseases in mice."
Cantorna detailed her research in a paper, "Vitamin D Deficiency Exacerbates Experimental Inflammatory Bowel Disease," presented today (April 18) at the Experimental Biology conference in San Diego, Calif. Her co-authors are Carey Munsick, a Penn State undergraduate, and Candace Bemiss, a Penn State master's degree candidate in nutrition. Their paper is the first in which researchers report demonstrating a connection between vitamin D deficiency and inflammatory bowel disease (IBD).
In her team's experiments, mice genetically engineered to spontaneously develop the symptoms of either Chron'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.
EDITORS: Dr. Cantorna is at 814-863-2819 or email@example.com by email.