A gluten-free diet is a cornerstone of managing the very real and serious autoimmune condition of coeliac disease. But the recent popularity of adopting gluten-free diets has had little to do with any change in the rates of diagnosis of coeliac disease. Instead, the dietary trend has grown from a perceived epidemic of self-diagnosed ‘gluten intolerance’.
The question of whether non-coeliac gluten sensitivity (NCGS) is a real condition or not is a vexed question. The first thing to note is that NCGS is not a diagnosable condition like coeliac disease. Diagnosis of NCGS relies on self-reported symptoms such as abdominal pain, bloating, nausea, and fatigue experienced after the consumption of gluten-contain foods. But that does not prove that it is gluten causing the problems as there is more to cereal foods than just gluten.
Several small research studies have found mixed evidence that people respond with defined gastrointestinal symptoms when challenged with gluten in blinded dietary trials. This has lead researchers to propose that self-reported gluten sensitivity may just be a marker for dietary changes that reduce the number of other food components that can cause gastrointestinal problems.
Adding another piece to the incomplete puzzle of NCGS, a new study set out to characterise the response to an oral gluten challenge in people who previously found symptom relief when following a gluten-free diet.
In the latest study, 20 people with suspected NCGS and who were already following a gluten-free diet, went through several 4-day periods of eating a muffin daily with or without added gluten. Both the volunteers and the researchers were blinded to which muffins had gluten added. Gastrointestinal symptoms were carefully recorded over the study.
Going completely against the grain, so to speak, gastrointestinal symptoms were in fact significantly more severe under the placebo muffin conditions which had no gluten in it whatsoever. And only four out of the 20 volunteers could correctly identify the two time periods when they were eating the gluten-containing muffin – hardly better than chance.
The results of this study, while small in size, adds more evidence to the pool that it is unlikely that gluten itself is a culprit in people reporting a wide range of irritable bowel-like symptoms. It doesn’t mean that such symptoms are all in the mind, only that it may be other ingredients found in cereal foods unrelated to gluten that could be causing the problem.