• What Is Irritable Bowel Syndrome?
• What Causes IBS?
• What Are the Symptoms of IBS?
• How Is IBS Diagnosed?
• How Do Diet and Stress Affect IBS?
• How Does a Good Diet Help IBS?
• Can Medicines Relieve IBS Symptoms?
• Is IBS Linked to Other Diseases?
• Additional Readings

Through the years, IBS has been called by many names--colitis, mucous colitis, spastic colon, spastic bowel, and functional bowel disease. Most of these terms are inaccurate. Colitis, for instance, means inflammation of the large intestine (colon). IBS, however, does not cause inflammation and should not be confused with another disorder, ulcerative colitis.

The cause of IBS is not known, and as yet there is no cure. Doctors call it a functional disorder because there is no sign of disease when the colon is examined. IBS causes a great deal of discomfort and distress, but it does not cause permanent harm to the intestines and does not lead to intestinal bleeding of the bowel or to a serious disease such as cancer. Often IBS is just a mild annoyance, but for some people it can be disabling. They may be unable to go to social events, to go out to a job, or to travel even short distances. Most people with IBS, however, are able to control their symptoms through medications prescribed by their physicians, diet, and stress management.

Colon motility (contraction of intestinal muscles and movement of its contents) is controlled by nerves and hormones and by electrical activity in the colon muscle. The electrical activity serves as a "pacemaker" similar to the mechanism that controls heart function.

Movements of the colon propel the contents slowly back and forth but mainly toward the rectum. A few times each day strong muscle contractions move down the colon pushing fecal material ahead of them. Some of these strong contractions result in a bowel movement.

Because doctors have been unable to find an organic cause, IBS often has been thought to be caused by emotional conflict or stress. While stress may worsen IBS symptoms, research suggests that other factors also are important. Researchers have found that the colon muscle of a person with IBS begins to spasm after only mild stimulation. The person with IBS seems to have a colon that is more sensitive and reactive than usual, so it responds strongly to stimuli that would not bother most people.

Ordinary events such as eating and distention from gas or other material in the colon can cause the colon to overreact in the person with IBS. Certain medicines and foods may trigger spasms in some people. Sometimes the spasm delays the passage of stool, leading to constipation. Chocolate, milk products, or large amounts of alcohol are frequent offenders. Caffeine causes loose stools in many people, but it is more likely to affect those with IBS. Researchers also have found that women with IBS may have more symptoms during their menstrual periods, suggesting that reproductive hormones can increase IBS symptoms.

People with IBS, on the other hand, usually have crampy abdominal pain with painful constipation or diarrhea. In some people, constipation and diarrhea alternate. Sometimes people with IBS pass mucus with their bowel movements. Bleeding, fever, weight loss, and persistent severe pain are not symptoms of IBS but may indicate other problems.

Eating causes contractions of the colon. Normally, this response may cause an urge to have a bowel movement within 30 to 60 minutes after a meal. In people with IBS, the urge may come sooner with cramps and diarrhea.

The strength of the response is often related to the number of calories in a meal and especially the amount of fat in a meal. Fat in any form (animal or vegetable) is a strong stimulus of colonic contractions after a meal. Many foods contain fat, especially meats of all kinds, poultry skin, whole milk, cream, cheese, butter, vegetable oil, margarine, shortening, avocados, and whipped toppings.

Stress also stimulates colonic spasm in people with IBS. This process is not completely understood, but scientists point out that the colon is controlled partly by the nervous system. Stress reduction (relaxation) training or counseling and support help relieve IBS symptoms in some people. However, doctors are quick to note that this does not mean IBS is the result of a personality disorder. IBS is at least partly a disorder of colon motility.

Dietary fiber may lessen IBS symptoms in many cases. Whole grain breads and cereals, beans, fruits, and vegetables are good sources of fiber. Consult your doctor before using an over-the-counter fiber supplement. High-fiber diets keep the colon mildly distended, which may help to prevent spasms from developing. Some forms of fiber also keep water in the stools, thereby preventing hard stools that are difficult to pass. Doctors usually recommend that you eat just enough fiber so that you have soft, easily passed, and painless bowel movements. High-fiber diets may cause gas and bloating, but within a few weeks, these symptoms often go away as your body adjusts to the diet.

Large meals can cause cramping and diarrhea in people with IBS. Symptoms may be eased if you eat smaller meals more often or just eat smaller portions. This should help, especially if your meals are low in fat and high in carbohydrates such as pasta, rice, whole-grain breads and cereals, fruits, and vegetables.

It is important to follow the physician's instructions when taking IBS medications--particularly laxatives, which can be habit forming if not used carefully.

• Scanlon, D, Becnel, B. Wellness Book of IBS. New York: St. Martin's Press, 1989. Practical patient's guide to coping with IBS written by a registered dietitian. Available in libraries and bookstores.

• Shimberg, E. Relief From IBS. New York: M. Evans and Company, 1988. Practical book for patients offers information about IBS symptoms, diet, treatment, and self-care. Available in libraries and bookstore BORDER=0 ALT="Publications">
  
  
  
  

e-text posted: February 1998
e-text last updated: November 2000