In a tell-all era in which almost no topic is taboo, only a small number of Americans with irritable bowel syndrome (IBS) discuss their symptoms with their doctors, let alone anyone else. When they do speak up, it’s because the constipation, diarrhea or pain has gotten so disruptive that it's affecting their ability to function on the job, dine out or exercise. Experts estimate that about 20 percent of Americans (most of them women) have IBS and roughly the same percentage seek medical care for it. "Some people don't find their IBS symptoms bothersome or unusual, and some may be shy about talking to a doctor about bowel problems," says gastroenterologist G. Richard Locke, M.D., professor of medicine at the Mayo Clinic College of Medicine in Rochester, Minn. IBS is a combination of symptoms that may include abdominal pain, cramps, bloating, flatulence, mucus in the stool, food intolerances, constipation or diarrhea (often alternating between the two). The diagnostic criteria include having abdominal pain or discomfort for at least 12 weeks out of the previous 12 months, not necessarily consecutively. Generally, pain is relieved by a bowel movement; their frequency alters when pain or discomfort begins; and/or there are changes in the form or appearance of the stool. "For most people, symptoms occur now and then, a couple of days a week or so," says Locke. "To meet the definition of IBS, you have to have the symptoms 25 percent [or more] of the time."
What causes IBS? IBS appears to stem from a disturbance in the interaction between the digestive tract, the brain and the autonomic nervous system. As a result, the colon can move too fast, resulting in diarrhea, or too slowly, resulting in constipation; sometimes it’s spasmodic. “IBS used to be called spastic colon or spastic colitis, but those terms are not accurate,” says Lin Chang, M.D., professor of medicine in the division of digestive diseases at the University of California, Los Angeles, David Geffen School of Medicine. Irritable bowel syndrome is also often confused with a category of conditions known as inflammatory bowel disease (see “IBS Look-alikes” on pg. 51.) The good news is that IBS has not been linked to these more serious bowel problems; nor does it raise the risk of colon cancer. “IBS is not a life-threatening condition, but it is a nuisance,” says Keith Bruninga, M.D., a gastroenterologist at Rush University Medical Center in Chicago. IBS can also take a financial and emotional toll, with patients reporting missed work, sleep problems, low energy, reduced sexual interest and feelings of nervousness or hopelessness. “You don’t know when it’s going to come on,” notes Chang. “You don’t know how long it’s going to last, and you don’t know what might trigger it. There’s constant anticipation.”