Increasing numbers of people are following a gluten-free diet, but often without clinical evidence that they need to.
This is according to a new study published in JAMA Internal Medicine, which shows that the gluten-free diet has become one of the most popular food trends in recent years, with one in five individuals in the US eliminating or reducing gluten in their diet.
However, the numbers diagnosed with coeliac disease or wheat allergy has remained stable.
An accompanying journal commentary suggests that the gluten-free diet trend may be partly driven by belief, fuelled by marketing and media, rather than a rise in clinical conditions.
“There is absolutely no evidence that wheat-free diets are intrinsically ‘healthy’,” says Anthony Frew, Professor of Allergy & Respiratory Medicine, Royal Sussex County Hospital in the UK, in response to the study.
However, he notes that some people who aren’t coeliac are intolerant of wheat and can get bloating, abdominal discomfort and variable bowel movements after eating it, which most doctors would label as irritable bowel syndrome (IBS).
“This is not a new phenomenon and relates to undigested wheat getting into the large bowel where it is fermented and produces gas which in turns causes bloating, wind etc,” he says.
Reducing the intake of wheat in people with IBS often find their symptoms improve, but this needs to be understood as an intolerance rather than a food allergy.
“Many people with intolerance refer to themselves as being ‘allergic to wheat’,” he says. “This is not technically correct: in medicine an allergy means you have an immune reaction against the offending product … IBS sufferers do not have an immune reaction to wheat.
“Complete avoidance of wheat is not usually necessary to relieve IBS symptoms, whereas in coeliac disease there is an immune reaction against wheat proteins (gluten).”
Professor Alastair Watson, Institute of Food Research, and Professor of Translational Medicine, UEA, agrees. Previous research has shown that the stomach and bowel symptoms in patients who don’t have coeliac disease can be improved when they go on a gluten-free diet.
“However it seems likely that the majority of people who put themselves on a gluten-free diet do so as a lifestyle choice. This new research shows how popular lifestyle gluten free diets have become.”