Irritable bowel syndrome.

Irritable bowel syndrome (IBS) is a baffling medical problem. Though you may have episodes of intense abdominal pain, tests may fail to uncover anything wrong.

In the past, physicians tended to minimize the symptoms of IBS. "They'd tell people, 'Tests show you don't have colon cancer or colitis. All you have is a dysfunction,'" says Sidney F. Phillips, a Mayo Clinic gastroenterologist.

"That's changed. Now we're saying, 'Yes, I know what you have. IBS is the most common reason patients come to me. Let's work to minimize your symptoms.' This attitude in itself can be extremely helpful," according to Phillips.

IBS is a disorder in how your bowel works. It's annoying, painful, and sometimes embarrassing, but not life-threatening and certainly not uncommon.

About one in five adult Americans has symptoms of IBS; less than half of these people seek help.

Some physicians rank the disorder with the common cold as a major cause of time lost from work.

In the United States, two to four times more women are treated for IBS than men. That's probably because women tend to seek medical help more frequently than men.

Stress and depression are often blamed as causes of IBS. But these emotions only aggravate the condition. The true cause of IBS is unknown.

Symptoms, which may include abdominal pain, diarrhea, constipation, and gas probably are caused by muscle spasms in the wails of your stomach or bowel.

Although bowel movements temporarily relieve the pain, you may feel as if you can't empty your bowels completely. Your stools can be ribbonlike and laced with mucus, or they can be hard, dry pellets. You may have bloating and nausea, too.

Unfortunately, there's no proven way to prevent IBS.

If you have symptoms of IBS, see your physician. Only your doctor can say for sure if your problem is IBS and not cancer, gallbladder disease, an ulcer, or another digestive system condition with similar symptoms.

You often need treatment for years. "IBS waxes and wanes," says Phillips, "and no single treatment puts everything right." But there's also good news--simple measures often relieve symptoms. For example, pay attention to eating habits that seem to irritate your IBS, and change your ways, if necessary. It might help to eat on a more regular schedule.

Don't overeat, and don't eat on the run. Slow down. Enjoy your food. Urgency and overeating can aggravate bowel irregularity.

In addition to these measures, your doctor and registered dietitian may recommend the following:

* Add fiber to your diet. Fiber helps prevent constipation. Sources include fruits, vegetables, bran and other whole grains, and legumes such as kidney, pinto, and garbanzo beans.

Because fiber can cause gas, especially when you first increase fiber in your diet, add it gradually. This way you'll minimize potential problems with gas.

* Avoid substances that irritate your bowel. Common irritants include tobacco, alcohol, caffeine, spicy foods, concentrated fruit juices (such as orange juice), and raw fruits or vegetables. They can cause diarrhea.

Also avoid fatty foods. "Fat stimulates your bowels more than any other food," says Phillips.

* Limit dairy products. Occasionally milk can cause abdominal cramping, gas, and diarrhea, especially if you lack adequate amounts of lactase, an intestinal enzyme that you need to digest milk sugar.

* Avoid dietetic sweeteners. Sweeteners such as sorbitol or manitol, often present in sugar-free candy, gum, and dietetic foods, can cause diarrhea.

But remember this about your diet--what works for others may not work for you. Trial and error is your best approach.

Eat the foods that best agree with you, based on your personal experience.

Your physician also may advise you to avoid medications that irritate your bowel. Or he or she may suggest ways to manage stress or depression.

Tension-relieving activities such as sports, hobbies, or regular physical exercise can help. Your doctor might suggest walking for 20 to 30 minutes three times a week, or swimming on a similar schedule.

Remember, if you are 40 years old or older, check with your doctor before beginning any exercise program.

If simple treatment measures don't help, your physician may recommend drug therapy.

IBS is a disorder that doesn't disappear easily, but take a positive approach. With help from your physician and registered dietitian, you can adopt diet and lifestyle changes that can help keep symptoms in check, usually without drugs.

(C) 1993, The Mayo Foundation for Medical Education and Research. Reprinted with permission from the Mayo Clinic Health Letter. Distributed by the Los Angeles Times Syndicate.