People with irritable bowel syndrome (IBS) often eliminate certain foods from their diet to avoid unpleasant symptoms from this gastrointestinal disorder. However, recent study findings published in the American Journal of Clinical Nutrition show that specific types of carbohydrates classified as “fodmaps” and gluten, both believed to exacerbate IBS symptoms, may be less harmful than previously thought, according to a press release from Chalmers University of Technology in Gothenburg, Sweden.

IBS is characterized by a group of symptoms that occur together, including repeated pain in the abdomen and changes in bowel movements. About 12% of people in the United States have IBS, which, while not life-threatening, can be difficult to live with, especially since there’s no cure for the condition.

For the study, a team of researchers from Chalmers and Uppsala University recruited 110 participants with IBS to eat rice puddings made with fodmaps—short for fermentable oligosaccharides, disaccharides, monosaccharides and polyols—and gluten prepared in three different ways. (The amount of fodmaps and gluten were 1.5 times the amount people normally ingest.)

Some examples of fodmaps are fructose, lactose, fruct/galacto-oligosaccharides and sugar alcohols, which are found in dairy products, cereals, mushrooms, fruits and vegetables.

One type of rice pudding contained plenty of fodmaps; the other included large amounts of gluten; and the third, which served as a placebo, did not contain any of these ingredients.

Scientists instructed individuals to eat one type of pudding per week in random order. In this double-blind study, neither the participants nor the researchers were aware of who ate a specific type of pudding or when.

Results showed that participants who ate the puddings containing fodmaps experienced aggravated symptoms of IBS, such as stomach pain, diarrhea and constipation. However, scientists noted that these issues occurred less often than expected based on previous study findings.

In addition, the rice puddings with gluten provoked negligible effects on any symptoms individuals noticed.

“Our results are important and indicate that the psychological factor is probably very important. IBS has previously been shown to be linked to mental health,” said Per Hellström, MD, PhD, a professor of gastroenterology at Uppsala who supervised the investigation. “Simply the awareness that one is being tested in a study can reduce the burden of symptoms.”

Interestingly, prior studies show that when fodmaps were excluded from people’s diets, they experienced less IBS symptoms. But these inquiries included few participants and were not double-blind studies.

Investigations to see what happens if IBS patients’ avoid gluten have thus far been inconclusive. Gluten-rich foods, such as bread, also contain lots of fodmaps, which has fueled speculation that fodmaps are the culprit in these types of foods that give IBS patients grief, not gluten.

The researchers are searching for biomarkers in gut bacteria or blood that might enable them to forecast health outcomes and categorize individuals based on their metabolism and how the organisms in their gut react to various diets. This might help those with IBS.

“Even if at group level we only see a moderate effect from fodmaps and no effect of gluten provocation, it may well still be the case that some individuals react strongly to these foods,” explained Elise Nordin, a PhD student in the department of biology and biotechnology at Chalmers. “That is why it is important to account for individual differences.”

To learn more about IBS, read "Tummy Troubles."