When IBS is diarrhea-predominant, a doctor may prescribe an antimotility agent to assist patients with symptoms (1). He or she may also prescribe an antibiotic if the IBS is a result of small intestinal bacterial overgrowth (1).
As a dietary aid for patients, a nutritionist may suggest soluble fiber such as from oats because it can help act against symptoms such as diarrhea by helping bind fat and slow emptying of food from the stomach into the small intestine (2).
The soluble fiber can include prebiotics such as fructo-oligosaccharides or resistant maltodextrin, which support growth of healthy intestinal bacteria. The prebiotics taken in conjunction with probiotics particularly after antibiotic therpay may help with promoting the growth of the good bacteria. This integrative therapy can help to alleviate symptoms by promoting competition against small intestinal bacterial growth (3).
Nutrionists should recommend suspending intake of insoluble fiber such as from wheat and cereal grains and limiting poorly-digested carbohydrates and sugar alcohols as these can worsen symptoms (4). Patients may find benefit from following an exclusion diet whereas trigger foods are eliminated and then, if thought advisable, reintroduced gradually (4).
1. Kohlstadt I. Food and Nutrients in Disease Management. Boca Raton, FL: CRC Press, 2009.
2. Bijkerk CJ, de Wit NJ, Muris JWM, Whorwell PJ, Knottnerus JA, Hoes AW. Soluble or insoluble fibre in irratble bowel syndrome in primary care? Randomized placebo controlled trial. Brit Med Jour 2009;339:b3154. Available at http://www.bmj.com/cgi/content/abstract/339/aug27_2/b3154. Accessed on March 31, 2010.
3. American College of Gastroenterology (2008, October 10). How Effective Are Probiotics In Irritable Bowel Syndrome?. ScienceDaily. Available at http://www.sciencedaily.com /releases/2008/10/081006092656.htm. Accessed on March 31, 2010.
4. Heizer WD, Southern S, McGovern S. The role of diet in symptoms of irritable bowel syndrome in adults: a narrative view. J Am Diet Assoc. 2009 Jul;109(7):1204-1.