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Irritable bowel syndrome (IBS) is a dis- order that interferes with the normal functions of the (colon). It is characterized by a group of symp- National Institute of toms—crampy , , Diabetes and , and diarrhea. Digestive and Kidney One in five Americans has IBS, making it Diseases one of the most common disorders diag- NATIONAL nosed by doctors. It occurs more often in INSTITUTES OF HEALTH women than in men, and it usually begins around age 20. IBS causes a great deal of discomfort and distress, but it does not permanently harm the intestines and does not lead to intestin- al bleeding or to any serious such as cancer. Most people can control their symptoms with diet, stress management, • The normal motility of the colon may and medications prescribed by their physi- not work properly. It can be spas- cian. But for some people, IBS can be dis- modic or can even stop temporarily. abling. They may be unable to work, go to Spasms are sudden strong muscle social events, or travel even short distances. contractions that come and go. • The lining of the colon (epithelium), What causes IBS? which is affected by the immune and What causes one person to have IBS and nervous systems, regulates the passage not another? No one knows. Symptoms of fluids in and out of the colon. In cannot be traced to a single organic cause. IBS, the epithelium appears to work Research suggests that people with IBS properly. However, fast movement of seem to have a colon that is more sensitive the colon’s contents can overcome the and reactive than usual to a variety of absorptive capacity of the colon. The things, including certain and stress. result is too much fluid in the stool. Some evidence indicates that the immune In other patients, colonic movement is system, which fights , is also too slow, too much fluid is absorbed, involved. IBS symptoms result from the and constipation develops. following: • The colon responds strongly to stimuli (for example, foods or stress) that U.S. Department would not bother most people. of Health and Human Services In people with IBS, stress and emotions trolled by the autonomic nervous system, can strongly affect the colon. It has many which has been proven to respond to stress. nerves that connect it to the brain. Like the For example, when you are frightened, your heart and the lungs, the colon is partly con- heart beats faster, your blood pressure may go up, or you may gasp. The colon responds to stress also. It may contract too What does the colon do? much or too little. It may absorb too much or too little. The colon, which is about 5 feet long, connects the with the Research has shown that very mild or hid- and anus. The major function den (occult) celiac disease is present in a of the colon is to absorb water, nutri- smaller group of people with symptoms ents, and salts from the partially di- that mimic IBS. People with celiac disease gested that enters from the small cannot digest gluten, which is present in intestine. Two pints of liquid matter wheat, rye, barley, and possibly oats. Foods enter the colon from the small intestine containing gluten are toxic to these people, each day. Stool volume is a third of a and their responds by pint. The difference in volume repre- damaging the small intestine. A blood sents what the colon absorbs each day. test can determine whether celiac disease is present. (For information about celiac Colon motility (the contraction of the disease, see the Celiac Disease fact sheet colon muscles and the movement of its from the National Institute of Diabetes and contents) is controlled by nerves and Digestive and Kidney Diseases (NIDDK).) hormones and by electrical activity in the colon muscle. Contractions move The following have been associated with a the contents slowly back and forth but worsening of IBS symptoms: mainly toward the rectum. During this passage, water and nutrients are • large meals absorbed into the body. What remains • bloating from gas in the colon is stool. A few times each day, strong muscle contractions move down the • medicines colon, pushing the stool ahead of them. • wheat, rye, barley, chocolate, Some of these strong contractions result products, or alcohol in a bowel movement. The muscles of the pelvis and anal sphincters have to • with caffeine, such as coffee, relax at the right time to allow the stool tea, or colas to be expelled. If the muscles of the • stress, conflict, or emotional upsets colon, sphincters, and pelvis do not con- tract in a coordinated way, the contents Researchers have also found that women do not move smoothly, resulting in with IBS may have more symptoms during abdominal pain, cramps, constipation their menstrual periods, suggesting that or diarrhea, and a sense of incomplete reproductive hormones can exacerbate stool movement. IBS problems.

2 Irritable Bowel Syndrome What are the symptoms of IBS? Criteria for IBS Diagnosis Abdominal pain or discomfort in associa- • Abdominal pain or discomfort for at tion with bowel dysfunction is the main least 12 weeks out of the previous 12 symptom. Symptoms may vary from person months. These 12 weeks do not have to person. Some people have constipation to be consecutive. (hard, difficult-to-pass, or infrequent bowel • The abdominal pain or discomfort movements); others have diarrhea (fre- has two of the following three quent loose stools, often with an urgent features: need to move the bowels); and still others experience alternating constipation and – It is relieved by having a bowel diarrhea. Some people experience bloat- movement. ing, which is gas building up in the intes- – When it starts, there is a change tines and causing the feeling of pressure in how often you have a bowel inside the . movement. IBS affects the motility or movement of – When it starts, there is a change stool and gas through the colon and how in the form of the stool or the way fluids are absorbed. When stool remains in it looks. the colon for a long time, too much water is absorbed from it. Then it becomes hard and difficult to pass. Or spasms push the stool through the colon too fast for the flu- rule out other diseases. These tests may id to be absorbed, resulting in diarrhea. In include stool or blood tests, x rays, or addition, with spasms, gas may get trapped endoscopy (viewing the colon through a in one area or stool may collect in one flexible tube inserted through the anus). If place, temporarily unable to move forward. these tests are all negative, the doctor may diagnose IBS based on your symptoms: Sometimes people with IBS have a crampy that is, how often you have had abdominal urge to move their bowels but cannot do so pain or discomfort during the past year, or pass mucus with their bowel movements. when the pain starts and stops in relation Bleeding, , , and persistent to bowel function, and how your bowel fre- severe pain are not symptoms of IBS and quency and stool consistency are altered. may indicate other problems such as inflammation or rarely cancer. What is the treatment for IBS? How is IBS diagnosed? No cure has been found for IBS, but many If you think you have IBS, seeing your doc- options are available to treat the symptoms. tor is the first step. IBS is generally diag- Your doctor will give you the best treat- nosed on the basis of a complete medical ments available for your particular symp- history that includes a careful description toms and encourage you to manage stress of symptoms and a physical examination. and make changes to your diet. No particular test is specific for IBS. How- Medications are an important part of ever, diagnostic tests may be performed to relieving symptoms. Your doctor may

3 Irritable Bowel Syndrome suggest fiber supplements or occasional lax- The colon has a vast supply of nerves that atives for constipation, as well as medicines connect it to the brain. These nerves con- to decrease diarrhea, tranquilizers to calm trol the normal rhythmic contractions of you, or drugs that control colon muscle the colon and cause abdominal discomfort spasms to reduce abdominal pain. Antide- at stressful times. People often experience pressants may also relieve some symptoms. cramps or “butterflies” when they are nerv- Medications available to treat IBS specifi- ous or upset. But with IBS, the colon can cally are the following: be overly responsive to even slight conflict or stress. Stress also makes the mind more • Alosetron hydrochloride (Lotronex) tuned to the sensations that arise in the has been re-approved by the U.S. colon and makes the stressed person per- Food and Drug Administration (FDA) ceive these sensations as unpleasant. for women with severe IBS who have not responded to conventional therapy Some evidence suggests that IBS is affected and whose primary symptom is diar- by the immune system, which fights infec- rhea. However, even in these patients, tion in the body. The immune system is it should be used with caution because also affected by stress. For all these rea- it can have serious side effects, such as sons, stress management is an important severe constipation or decreased blood part of treatment for IBS. Stress manage- flow to the colon. ment comprises • Tegaserod maleate (Zelnorm) has • stress reduction (relaxation) training been approved by the FDA for the and relaxation therapies, such as short-term treatment (usually 4 weeks) meditation of women with IBS whose primary • counseling and support symptom is constipation. • regular exercise such as walking or With any medication, even over-the- yoga counter medications such as and fiber supplements, it is important to follow • changes to the stressful situations your doctor’s instructions. Laxatives can be in your life habit forming if they are not used carefully or are used too frequently. • adequate sleep It is also important to note that medica- tions affect people differently and that no Can changes in diet one medication or combination of medica- help IBS? tions will work for everyone with IBS. For many people, careful eating reduces You need to work with your doctor to find IBS symptoms. Before changing your diet, the best combination of medicine, diet, keep a journal noting the foods that seem counseling, and support to control your to cause distress. Then discuss your find- symptoms. ings with your doctor. You may also want to consult a registered dietitian, who can How does stress affect IBS? help you make changes to your diet. For instance, if dairy products cause your symp- Stress—feeling mentally or emotionally toms to flare up, you can try eating less of tense, troubled, angry, or overwhelmed— those foods. You might be able to tolerate stimulates colon spasms in people with IBS. better than other dairy products

4 Irritable Bowel Syndrome because it contains that supply Is IBS linked to other the needed to digest , the found in milk products. Dairy prod- diseases? ucts are an important source of calcium IBS itself is not a disease. As its name and other nutrients. If you need to avoid indicates, it is a syndrome—a combination dairy products, be sure to get adequate of . But IBS has not nutrients in the foods you substitute or been shown to lead to any serious, organic take supplements. diseases, including cancer. Through the years, IBS has been called by many names, In many cases, may lessen among them , mucous colitis, spastic IBS symptoms, particularly constipation. colon, or spastic bowel. However, no link However, it may not help pain or diarrhea. has been established between IBS and Whole grain breads and cereals, fruits, and inflammatory bowel diseases such as vegetables are good sources of fiber. High- Crohn’s disease or . fiber diets keep the colon mildly distended, which may help prevent spasms. Some forms of fiber also keep water in the stool, Hope Through Research thereby preventing hard stools that are dif- The NIDDK conducts and supports ficult to pass. Doctors usually recommend research into many kinds of digestive dis- a diet with enough fiber to produce soft, orders, including IBS. Researchers are painless bowel movements. High-fiber studying gastrointestinal motility and sen- diets may cause gas and bloating, but these sitivity to find possible treatments for IBS. symptoms often go away within a few weeks These studies include the structure and as your body adjusts. (For information contraction of gastrointestinal muscles as about diets for people with celiac disease, well as the mechanics of fluid movement please see the Celiac Disease fact sheet through the intestines. Understanding the from NIDDK.) influence of the nerves, hormones, and inflammation in IBS may lead to new treat- Drinking six to eight glasses of plain water ments to better control the symptoms. a day is important, especially if you have diarrhea. But drinking carbonated bever- ages, such as sodas, may result in gas and For More Information cause discomfort. Chewing gum and eating International Foundation for Functional too quickly can lead to swallowing air, Gastrointestinal Disorders which again leads to gas. P.O. Box 170864 Also, large meals can cause cramping and Milwaukee, WI 53217 diarrhea, so eating smaller meals more Phone: 1–888–964–2001 or 414–964–1799 often or eating smaller portions should help Fax: 414–964–7176 IBS symptoms. It may also help if your Email: [email protected] meals are low in fat and high in carbohy- Internet: www.iffgd.org drates, such as pasta, , whole-grain breads and cereals (unless you have celiac disease), fruits, and vegetables.

5 Irritable Bowel Syndrome National Digestive Diseases Points to Remember Information Clearinghouse • IBS is a disorder that interferes with the normal functions of the colon. 2 Information Way Bethesda, MD 20892–3570 The symptoms are crampy abdomi- Phone: 1–800–891–5389 nal pain, bloating, constipation, and Fax: 703–738–4929 diarrhea. Email: [email protected] • IBS is a common disorder found Internet: www.digestive.niddk.nih.gov more often in women than in men The National Digestive Diseases Information and usually begins around age 20. Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive • People with IBS have colons that are and Kidney Diseases (NIDDK). The NIDDK more sensitive and react to things is part of the National Institutes of Health that might not bother other people, under the U.S. Department of Health and such as stress, large meals, gas, medi- Human Services. Established in 1980, the cines, certain foods, caffeine, or clearinghouse provides information about alcohol. digestive diseases to people with digestive disorders and to their families, health care • IBS is diagnosed by its symptoms and professionals, and the public. NDDIC answers by the absence of other diseases. inquiries, develops and distributes publications, • Most people can control their symp- and works closely with professional and patient toms by taking medicines (laxatives, organizations and Government agencies to antidiarrhea medicines, tranquilizers, coordinate resources about digestive diseases. or antidepressants), reducing stress, Publications produced by the clearinghouse are and changing their diet. carefully reviewed by both NIDDK scientists and outside experts. This fact sheet was • IBS does not harm the intestines and reviewed by Michael Camilleri, M.D., Mayo does not lead to cancer. It is not Clinic Rochester. related to Crohn’s disease or ulcera- tive colitis.

This publication is not copyrighted. The clearinghouse encourages users of this fact sheet to duplicate and distribute as many The U.S. Government does not endorse or favor copies as desired. any specific commercial product or company. Trade, proprietary, or company names appearing This fact sheet is also available at in this document are used only because they are www.digestive.niddk.nih.gov. considered necessary in the context of the infor- mation provided. If a product is not mentioned, the omission does not mean or imply that the product is unsatisfactory.

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health

NIH Publication No. 03–693 April 2003