For people with irritable bowel syndrome, conventional wisdom has long said to avoid certain foods. Those include dairy products and certain fruits and vegetables. Now, a new study suggests that the effects of specific diets on IBS may be overstated.

Researchers at two universities in Sweden have found that eating more gluten is not associated with an increase in IBS symptoms. Gluten, which is a protein found in wheat and other grains, has traditionally been off limits to many people with IBS. The disorder affects 3% to 5% of the world’s population and causes stomach pain, constipation or diarrhea.

During the study, 110 people ate rice pudding that had been prepared in various ways. Some of the puddings were gluten rich, while others contained heavy amounts of fermentable carbohydrates. IBS patients have traditionally been advised to limit their consumption of dairy products, some breads, and certain fruits and vegetables containing fermentable carbohydrates.

Over a three-week period, the study participants ate rice puddings containing high gluten, fermentable carbohydrates and a placebo for one week each.  Neither the participants nor the scientists knew who was eating which variety of pudding and when — an important step to assure valid results.

The high doses of fermentable carbohydrates provoked the subjects’ gastrointestinal systems, but not to the extent that earlier studies had suggested. Gluten was found to have no measurable negative effects on the participants’ perceived IBS symptoms.

Because many people with IBS automatically avoid gluten-heavy foods, the scientists say the ultimate answer about what triggers it may lie in biological markers in the gut or bloodstream.