Instead, the reaction could be caused by fructans, the sugar chains that are found in wheat, barley and rye.
Researchers from Monash University in Australia suspected that sugar could be the real culprit because people with irritable bowel syndrome (IBS) still have some of the symptoms even after following a strict gluten-free diet, and in a 2013 research project, they noticed that the symptoms of people with gluten intolerance didn't change, whether they ate food that was rich in gluten or not.
So they decided to test the theory further. They got together 59 people who were gluten intolerant, and gave them a different cereal bar to eat for a week. Although the bars all looked the same, one contained gluten, another fructans and the third had neither ingredient.
The fructans bar increased bloating by 15 per cent and gastro-intestinal problems by 13 per cent, and neither the gluten bar nor the one without any ingredients had any effect.
If fructans are the real problem, people with gluten intolerance could use soy sauce—as it's low in the sugars—and eat sourdough bread that loses fructans in the baking process, the researchers say.