What Causes Irritable Bowel Syndrome?

by Dr. David Williams
Filed Under: IBS, Digestive Health
Last Reviewed 02/06/2014

Learn about common irritable bowel syndrome triggers

Irritable bowel syndrome can be a recurring and intermittent problem. In addition, several factors can trigger or contribute to the development of irritable bowel syndrome:

Antibiotic Use

For many people, irritable bowel syndrome symptoms first show up after an infection (often one in the gastrointestinal tract), particularly when a long course of treatment or potent antibiotics have been used to address the infection. Antibiotics disrupt the normal bacterial flora in the gut, and this imbalance can lead to irritable bowel syndrome.

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Food Intolerance

Intolerance to certain foods is one of the primary triggers of irritable bowel syndrome. Many people incorrectly refer to food intolerances as food "allergies," but ingesting the offending foods doesn’t trigger a reaction from the immune system the way a true allergy does. Studies have shown that irritable bowel syndrome patients can usually correct their problem by following a diet that eliminates offending foods. (Get detailed instructions on how to follow an elimination diet.)

One representative study involved 21 patients with irritable bowel syndrome. Symptoms in 14 of the patients disappeared completely after one week on a strict diet consisting of only one type of meat, a single type of fruit, and distilled or spring water. Various foods were then added to the diet—either orally or through a tube (so the patients wouldn’t know what was being eaten—which could affect the results). The following symptom-evoking foods were found (number of cases in parentheses): wheat (9), corn (5), dairy products (4), coffee (4), tea (3), and citrus fruits (2).

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Fructose Ingestion

One study suggests that fructose alone may be responsible for 30 to 60 percent of all cases of irritable bowel syndrome. Dr. Young Choi, at the University of Iowa Carver College of Medicine, tested the effects of fructose ingestion on 183 individuals over a two-year period. He consistently found that each of the irritable bowel syndrome symptoms could be triggered with increased ingestion of fructose, and that symptoms could be eliminated by avoiding fructose intake. The most common source of fructose in the American diet nowadays is high-fructose corn syrup (HFCS).

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Additional Triggers

Other factors that can cause irritable bowel syndrome include: stress, genetics, drugs, radiation therapy, smoking, alcohol use or abuse, carbonated beverages, lack of sleep and exercise, surgical trauma or injury to the bowel, eating disorders, and use of hormones (particularly oral contraceptives or hormone replacement therapy).

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More Dr. Williams Advice on Irritable Bowel Syndrome

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