A new study has revealed that although 20 per cent of adults in Britain — around ten million — claim they are unable to eat foods from milk to mustard, fewer than two per cent actually have a problem.

The researchers from Portsmouth University found the discrepancy after reviewing studies into the prevalence of food allergies, which are caused by an over-reaction of the immune system, and intolerances, which have similar but less severe symptoms, the British media reported.

They have blamed internet searches, self-testing kits and celebrity food fads for the epidemic of make-believe allergies and intolerances. As a result, they said millions are unnecessarily restricting their diets, starving themselves of their favourite foods and of key nutrients. Others could be suffering from another medical problem which goes untreated because they believe their symptoms are caused by a particular food such as milk, eggs or wheat, claim the researchers.

“There is a clear discrepancy between the number of people who report that they have food allergy or intolerance and the numbers whose food allergy or intolerance can be confirmed by a medical diagnosis.

“Diagnostic tests not conducted by qualified medical professionals are not reliable. Food allergy is usually investigated via a skin prick test by a medical professional with access to the patient’s clinical history, sometimes in conjunction with a period of eliminating the suspect food.

“Parents who believe their child has a food allergy may feel anxious about their health and go to great lengths to ensure their child avoids certain foods. Children are more prone to nutritional problems when foods are excluded from the diet so it’s critical that they receive a correct diagnosis,” Dr Carina Venter said.