How does inflammatory bowel disease interfere with digestion?
When the small intestine becomes inflamed, as in Crohn’s disease, it is less able to absorb nutrients from food. These nutrients leave the body in the bowel movement. This is one reason why people with Crohn’s disease don’t get enough nutrients, along with not having much appetite. Also, the undigested food that goes into the large intestine makes water absorption harder. This causes a watery bowel movement, or diarrhea. In ulcerative colitis, the small intestine absorbs nutrients as it should. But inflammation in the large intestine keeps it from absorbing water, causing diarrhea.