Researchers are attempting to draw a “clear line” between the people who benefit from a gluten-free diet and those who do not.

They say evidence is required to challenge the people who, by adopting a gluten-free diet as a lifestyle choice, are undermining attitudes towards people with coeliac disease or non-coeliac gluten sensitivity who do need to avoid gluten.

A small UK study, published in Gastroenterology, randomised 28 healthy adults to either gluten-containing flour or gluten-free flour in the context of a dietitian-supervised gluten-free diet.

Participants were serologically screened to exclude coeliac disease and none had previously been diagnosed with a gluten-related disorder.

The participants reported abdominal pain, reflux, indigestion, diarrhoea and constipation using the Gastrointestinal Symptom Rating Scale and global fatigue using a visual analogue scale at baseline and after two weeks on the diet.

The study found no significant differences between the groups with respect to changes in any symptoms.

“Our results support the view that gluten does not appear to cause symptoms in individuals who do not have a physiological susceptibility to it (i.e. the majority of the population),” the study authors said.

“As the GFD is not only thought to be no healthier than a “normal” diet, but has been suggested as overall sub-optimal, there is possibly clinical justification in actively discouraging people from starting it if they have no diagnosable sensitivity.”

“Patients who self-report symptoms related to gluten must have Celiac Disease and Non-Celiac Gluten Sensitivity excluded, but on the basis of this new data perhaps the assertion by ‘lifestylers’ that a GFD is beneficial can also be challenged.”