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Am Fam Physician. 2005;71(3):547-548

What is irritable bowel syndrome?

Irritable bowel syndrome (IBS) is a problem with the intestines. In people with IBS, the intestines squeeze too hard or not hard enough and food moves too quickly or too slowly through the intestines.

IBS also is called functional bowel syndrome, irritable colon (the large intestine also is called the colon), spastic bowel, and spastic colon. It is not the same as inflammatory bowel diseases like ulcerative colitis.

What are the symptoms of IBS?

The box below lists common symptoms of IBS. The symptoms may get worse when you are under stress, such as when you travel, attend social events, or change your daily routine. Your symptoms also may get worse if you do not eat a healthy diet or after you have eaten a big meal. Some people are bothered more by certain foods. Women who have IBS may notice symptoms during their menstrual periods.

Common Symptoms of IBS

  • Bloating and gas

  • Constipation

  • Diarrhea, especially after eating or first thing in the morning

  • Feeling like you still need to have a bowel movement after you have already had one

  • Feeling a very strong urge to have a bowel movement

  • Abdominal pain and cramping that may go away after having a bowel movement

How is IBS diagnosed?

Your doctor may start by asking you questions about your symptoms. If your symptoms have had a pattern over time, the pattern may make it clear to your doctor that IBS is the cause.

If your symptoms have just started, something else may be the cause. Your doctor may need to do some tests, such as a blood test or colonoscopy, to make sure that your symptoms are not caused by something other than IBS.

How is IBS treated?

The best way to handle IBS is to eat a healthy diet, avoid foods that seem to make you feel worse, and find ways to handle your stress.

Why is fiber helpful?

Fiber can be helpful because it improves the way the intestines work. There are two kinds of fiber: soluble and insoluble. (Soluble means it dissolves in liquid.) Soluble fiber helps both diarrhea and constipation. Insoluble fiber may make diarrhea worse.

Insoluble fiber is in fruits, vegetables, whole grain breads, and cereals. Psyllium (say sillyum), which is a natural vegetable fiber, and oat bran are soluble fibers. You can buy psyllium (some brand names: Fiberall, Metamucil, Perdiem) at the store. Oat bran is in some cereals, bread, or muffins. You also can add it to other foods. You can find it in grocery stores and health food stores.

Increase the fiber in your diet little by little. Some people feel bloated and have gas if they add too much fiber too quickly. Gas and bloating usually go away as you get used to eating more fiber.

Do certain foods cause IBS?

No. Foods do not cause IBS. But some foods may make you feel worse. Things that may make symptoms worse include foods high in fat or caffeine. Fat and caffeine can make your intestines contract (squeeze), which may cause cramps. If gas is a problem for you, you might want to avoid foods that tend to make gas worse. These include beans, cabbage, and some fruits.

Keeping a diary of what you eat and what your symptoms are for a few weeks may be a good way to find out if a food bothers you. If you think a food makes you feel worse, try not eating it. But do not cut out foods unless they have caused you problems more than once.

What about milk and milk products?

If milk and other dairy products bother you, you may have lactose intolerance. Lactose intolerance means your body cannot digest lactose (the sugar in milk).

Dairy products may seem to make IBS symptoms worse if you are lactose intolerant. If this seems to be the case, you may need to limit the amount of milk and dairy products in your diet. Talk to your doctor if you think you have trouble digesting dairy products.

How can I manage my stress?

Talk to your doctor about ways to deal with stress, such as exercise, relaxation training, or meditation. Your doctor also may suggest that you talk to a counselor about things that are bothering you.

Can my doctor prescribe medicine for IBS?

There is no cure for IBS. However, if you are having bad symptoms, your doctor may prescribe medicine to help you manage them or make them less severe.

Will IBS get worse over time?

No. While IBS will probably happen throughout your life, it will not get worse. It does not cause cancer or require surgery, and it will not shorten your life.

Tips on Controlling IBS

  • Eat a varied diet and avoid foods high in fat.

  • Drink plenty of water.

  • Try eating six small meals a day rather than three larger ones.

  • Learn new and better ways to deal with your stress.

  • Avoid using laxatives (except soluble fibers). You may become dependent on them and your intestines could become weak.

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