Although high-fiber foods trigger the symptoms of irritable bowel syndrome in some people who have this disorder, a high-fiber diet may regulate your bowel movements if you suffer from frequent constipation. The type of fiber that you eat, the amount of fluids you drink and the size of your meals may also affect constipation in IBS. A gradual increase in dietary fiber and fluids combined with a fiber supplement may relieve the constipation associated with IBS.
IBS is a functional bowel disorder characterized by irregular bowel patterns, abdominal pain, gas and bloating. Muscle spasms in the colon may result in either diarrhea or constipation. If you frequently have dry, hard stools that are difficult to pass, you may have constipation-predominant IBS. When your intestinal muscles move too slowly to push digestive wastes through the colon, the colon absorbs too much water from these wastes. Increasing dietary fiber may stimulate muscle movement in the colon, restoring regular bowel patterns.
The University of Pittsburgh Medical Center recommends a high-fiber, low-fat diet to resolve constipation. Gradually increase your fiber intake until you are eating 20 to 35 grams of fiber per day. Foods such as whole-grain breads and cereals, fruits and vegetables and legumes are rich in fiber. To increase your fiber intake and reduce fat, replace meat with beans several times a week, snack on fruits or vegetables instead of chips or crackers, and replace one serving of cheese or meat at lunch or dinner with a salad or a serving of steamed vegetables. For breakfast, try oatmeal with bananas instead of a muffin or a doughnut.
Types of Fiber
Of the two forms of dietary fiber – soluble and insoluble – insoluble fiber tends to provoke more gastrointestinal reactions in people with IBS, explains the National Digestive Diseases Information Clearinghouse. Wheat bran, many vegetables and some fruits are high in insoluble fiber, which does not dissolve in your digestive tract. Though this rough form of fiber may relieve constipation by bulking up stools and stimulating your colon, many people with IBS report that it causes gas, bloating and diarrhea. Soluble fiber, found in whole oats, beans, apples and citrus fruits, forms a jelly-like substance that may also resolve constipation.
Adding fiber to your diet too quickly may worsen constipation. As you gradually increase your fiber intake, you should also increase your intake of water and other fluids to keep your stools soft. Eat four or five small meals each day, and monitor your reactions to high-fiber foods as you add them to your diet. Wheat is a common trigger for people with IBS, says the National Digestive Diseases Information Clearinghouse. If eating wheat provokes a flare-up of abdominal pain, gas or cramping, you may find that whole oats, which contain soluble fiber, relieve constipation without aggravating IBS symptoms. Eating smaller servings of high-fiber foods that cause gas, such as cabbage, broccoli or legumes, may reduce abdominal cramps.
Fiber supplements or laxatives may provide additional relief by accelerating the transit of stools through the colon. Although a high-fiber diet may resolve constipation, dietary changes may not resolve abdominal pain. Because the antispasmodic medications prescribed to control colon spasms may worsen constipation, your doctor may also prescribe a medication to relax your intestinal muscles. Work with your medical provider to develop a treatment plan that meets your needs.