Soluble Fiber May Help Irritable Bowel Symptoms
People who add soluble fiber to their diet may enjoy an improvement in symptoms of irritable bowel syndrome, according to a new study published in the British Medical Journal. Those who include insoluble fiber, however, may experience a worsening of symptoms.
Irritable bowel syndrome is a disorder that affects as many as 20 percent of adults in the United States. Women are affected more often than men, and the disease typically begins before age 35 in about 50 percent of people. Common symptoms include cramping, bloating, abdominal pain, constipation, and diarrhea. Unlike other gastrointestinal disorders such as Crohn’s disease and ulcerative colitis, irritable bowel syndrome does not damage the intestines and does not lead to cancer.
In the current trial, 275 patients with irritable bowel syndrome were assigned to receive either 10 grams of psyllium (a soluble fiber supplement), 10 grams of bran (insoluble fiber), or 10 grams of rice flour (placebo) daily for three months. Soluble fiber can dissolve in water and is found most fruits and vegetables. Insoluble fibers are commonly found in grains and contain cellulose, hemicellulose, and lignin, which are not dissolvable in water.
Patients who took psyllium (soluble fiber) daily reported a 90 point reduction in the severity of their symptoms, compared with 58 percent in the bran (insoluble fiber) group. Notable in the insoluble fiber group was a high rate of drop-outs early in the study because the patients experienced a worsening of their irritable bowel symptoms.
Currently there is no cure for irritable bowel syndrome, and intervention involves symptom management. In addition to taking soluble fiber, people who have irritable bowel syndrome can help prevent symptoms by avoiding caffeine products, chocolate, alcohol, wheat, barley, and milk products. Stress and eating large meals have also been linked to an exacerbation of irritable bowel symptoms.
Bijkerk CJ et al. British Medical Journal 2009 Aug 27; 339:b3154
National Institute of Diabetes and Digestive and Kidney Diseases