There are no proven health benefits to switching to a gluten-free diet unless a person has coeliac disease or an allergy to wheat, researchers have said.

People with coeliac disease are unable to digest gluten, a protein found in wheat, barley and rye. Symptoms can include weight loss, abdominal pain, diarrhoea, constipation and a failure to thrive in children. An estimated 46,000 people in Ireland are affected.

The only treatment for coeliac disease is a gluten-free diet, however, according to Dr Norelle Reilly of the Columbia University Medical Center in the US, there has been a disproportionate increase in the growth of the gluten-free food industry.

She noted that little is known about the motives of people who choose this type of diet when they do not have to. In fact, a US study of 1,500 people last year found that when asked why they had opted for this diet, ‘no reason' was the most common explanation.

"Out of concern for their children's health, parents sometimes place their children on a gluten-free diet in the belief that it relieves symptoms, can prevent coeliac disease, or is a healthy alternative without prior testing for coeliac disease or consultation with a dietitian," Dr Reilly noted.

However, she pointed out that it is a misconception that a gluten-free diet is a healthy lifestyle choice with no disadvantages. The reality is that unless you have coeliac disease or a wheat allergy, there are no proven health benefits to following this diet.

In fact for some people it could increase calorie and fat intake, contribute to nutritional deficiencies and make it more difficult to actually diagnose coeliac disease if it is present.

Dr Reilly said that another misconception is that gluten is toxic, however she noted that there is no evidence to support this idea.

She also pointed out that the healthy relatives of people with coeliac disease do not have to follow a gluten-free diet, nor do healthy infants at risk of developing the disease.

She acknowledged that for people with coeliac disease or a small number of patients who have been advised by a registered dietitian to follow this diet, it can lead to a better quality of life.

However, there is no scientific evidence that following this diet benefits people, including children, unless they have been diagnosed with coeliac disease or a wheat allergy.

"Parents should be counselled as to the possible financial, social, and nutritional consequences of unnecessary implementation of a gluten-free diet," she suggested.

She added that healthcare professionals may not be able to stop the move to a gluten-free diet, but they may be able to play a larger role in educating patients and parents.

Details of these findings are published in The Journal of Pediatrics.