That is interesting. Dr. Ronald Hoffman's Web site offers this information on a link between IBD and Vitamin D deficiency:
Vitamin D deficiency may be more common in people who have inflammatory bowel disease. Vitamin D deficiency may worsen the symptoms of Crohn's disease, but it's still unclear whether lack of the vitamin could be a cause, or simply an effect of the disease.
In a study, genetically engineered mice set to develop Crohn's disease and ulcerative colitis, were divided into two groups. Half were starved of vitamin D in their diet, while the other half were given a supplement. The treated mice not only had less bowel inflammation, but also survived when the untreated mice started dying after only a few weeks.
The research team pointed out other factors, which might suggest a link between IBD and vitamin D. Rates of IBD are higher in North America and Northern Europe, which receive less sunlight. However, a UK expert questioned whether vitamin D was the principal factor behind the high rates of Crohn's disease. Dr. Nick Thompson, a consultant gastroenterologist, carried out a study of 250 Crohn's patients and found only three who could be classified as Vitamin D deficient. He also pointed out that rickets has virtually disappeared in recent years, while Crohn's has soared.
It is interesting to note that patients with Crohn's disease may actually have high levels of vitamin D in their blood, indicating risk for toxicity if they took additional vitamin D. It may not be the best idea to start prescribing vitamin D for patients without testing 25 hydroxyvitamin D levels. As Abreu's team explains in the medical journal Gut, under certain circumstances too much active vitamin D can actually contribute to the breakdown of bone, leading to osteoporosis. In that same journal, researchers found "inappropriately high" blood levels of the active form of vitamin D in 42 percent of the 138 people they studied with Crohn's disease. This was true of only 7 percent of 29 patients with ulcerative colitis. In addition, the higher the blood levels of active vitamin D in Crohn's patients, the lower their bone density -- regardless of whether they were treated with steroids. The researchers believe that high vitamin D levels are most likely a manifestation of the underlying gut inflammation. Immune system cells produce vitamin D as part of the immune response (vitamin D is required for cell differentiation).
Bottom line: get a 25 hydroxyvitamin D blood test for patients with Crohn's or colitis. It seems that colitis patients are better candidates for medically supervised vitamin D therapy.