People who follow a gluten-free diet in the hope of it calming their irritable bowel syndrome may actually be able to tolerate the common dietary protein
By Carissa Wong
21 July 2025
Gluten is a protein found in most types of bread
TONO BALAGUER/Getty Images
Some people who think gluten worsens their irritable bowel syndrome (IBS) symptoms actually experience no more discomfort when they eat the protein, which is found in wheat, barley and rye.
IBS commonly causes abdominal pain, bloating, diarrhoea and constipation. While the mechanism is unknown, many people with the condition believe eating gluten or wheat, which contains gluten, worsens their symptoms.
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To understand whether these really are common triggers, Premysl Bercik at McMaster University in Canada and his colleagues recruited 28 people with IBS who said they had experienced improvements on a gluten-free diet.
The researchers asked the participants to eat a gluten-free diet for three weeks, before ranking the severity of their symptoms on a scale of 0 to 500, with an average score of 183.
They then randomly assigned the participants to eat one of three types of cereal bars, which looked and tasted the same, every day. One of the bars contained wheat, the second contained gluten but no other components of wheat and the third was a free of both ingredients. The first two bars contained doses of gluten equivalent to four slices of bread, says Bercik.