subject: Health effects of gluten [print this page] Crohn's Disease and Ulcerative Colitis-gluten may aggravate these illnesses, in which the bowel becomes chronically inflamed. Ulcerative Colitis affects the rectum and large intestine. Chrohn's Disease may affect any component of the gastro-intestinal tract. Weight loss, bloating. stomach pain and lethargy are some of the debilitating symptoms. Surgery is often required to relieve symptoms, through the removal of the affected areas.