Vitamin D supplements may protect against Crohn's disease

Research published in the January 22, 2010 issue of the Journal of Biological Chemistry describes how vitamin D could help protect against Crohn's disease, an inflammatory bowel disease that is believed to be caused by defective innate immune regulation of intestinal bacteria. Recent research has uncovered a difference in the rate of Crohn's disease according to latitude, suggesting that vitamin D from sunlight may be protective. Additionally, variations in the vitamin D receptor gene have been linked to susceptibility to Crohn's disease as well as to ulcerative colitis, another inflammatory bowel disease.

Researchers at McGill University in Montreal led by endocrinologist John H. White, in collaboration with scientists from the Université de Montréal, discovered that vitamin D acts on the beta defensin gene, which encodes an antimicrobial peptide. The vitamin also affects the NOD2 gene, which informs cells of the presence of invading micro-organisms. Defects in the NOD2 gene mean that the body cannot defend itself effectively against intestinal tract invaders. Both of these genes have been linked to the development of Crohn's disease.

"Our data suggests, for the first time, that vitamin D deficiency can contribute to Crohn's disease," stated Dr White, who is a professor in McGill's Department of Physiology. "Siblings of patients with Crohn's disease that haven't yet developed the disease might be well advised to make sure they're vitamin D sufficient. It's something that's easy to do, because they can simply go to a pharmacy and buy vitamin D supplements. The vast majority of people would be candidates for vitamin D treatment."

"This discovery is exciting, since it shows how an over-the-counter supplement such as vitamin D could help people defend themselves against Crohn's disease," noted coauthor Marc J. Servant, who is a professor at the Université de Montréal's Faculty of Pharmacy. "We have identified a new treatment avenue for people with Crohn's disease or other inflammatory bowel diseases."

Crohn's disease

Crohn’s disease can attack any portion of the digestive tract, although inflammation most commonly occurs in the lower portion of the small intestine, known as the ileum. The disease can cause ulcerations within the intestine that can erode into surrounding tissues such as the bladder (Sato S et al 1999), vagina (Feller ER et al 2001), or even the surface of the skin (Tavarela VF 2004). Inflammation in Crohn’s disease is not limited to the intestine—some people who have Crohn’s disease have inflammation of the eyes and joints as well.

The most common symptoms of the disease include severe abdominal pain with or without diarrhea. Diarrheal stool may be mixed with blood and often with mucus or pus. Bowel movements are often painful. Cramping in the right lower side of the abdomen is common, especially after meals. People with Crohn’s disease often have chronic low-grade fever, poor appetite, fatigue, and weight loss. Symptoms outside the gastrointestinal tract include joint pain and swelling, and occasionally eye pain and vision disturbances. Skin rashes may also occur. People who have Crohn’s disease almost always have some degree of anemia, related both to poor iron absorption and to chronic blood loss from inflamed tissue.

Guidelines produced by the American Society of Gastroenterology classify patients into mild-moderate, moderate-severe, or severe-fulminant disease categories. Those at the milder end of the spectrum can eat and function reasonably normally, while those at the severe end fail to respond to treatment and have persistent symptoms, fevers, and infections.

http://www.lef.org/newsletter/2010/0202_Vitamin-D-Supplements-May-Protect-Against-Crohns-Disease.htm