Diet, Stress and Irritable Bowel Syndrome (IBS)

How Do Diet and Stress Affect Irritable Bowel Syndrome (IBS)?

The potential for abnormal function of the colon is always present in people with IBS, but a trigger also must be present to cause symptoms. The most likely culprits seem to be diet and emotional stress. Many people report that their symptoms occur following a meal or when they are under stress. No one is sure why this happens, but scientists have some clues.

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.

How Does A Good Diet Help IBS?

For many people, eating a proper diet lessens IBS symptoms. Before changing your diet, it is a good idea to keep a journal noting which foods seem to cause distress. Discuss your findings with your doctor. You also may want to consult a registered dietitian, who can help you make changes in your diet. For instance, if dairy products cause your symptoms to flare up, you can try eating less of those foods. Yogurt might be tolerated better because it contains organisms that supply lactase, the enzyme needed to digest lactose, the sugar found in milk products. Because dairy products are an important source of calcium and other nutrients that your body needs, be sure to get adequate nutrients in the foods that you substitute.

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.

Additional Readings

• 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 bookstores.

• Steinhart, MJ. "Irritable bowel syndrome: How to relieve symptoms enough to improve daily function," Postgraduate Medicine 1992; 91(6): 315-321. Article for primary care physicians includes information about relief of IBS symptoms. Available in medical and university libraries.

• Thompson, WG. Gut reactions: Understanding symptoms of the digestive tract, New York: Plenum Publishing Corp., 1989. Clear, concise book by a digestive diseases specialist gives advice about diagnosis, diet, and treatment of IBS. Available in libraries and bookstores.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.