You eat raisins and become bloated? You drink a glass of milk and it rumbles inside you? You eat cheese and suddenly your head is humming?

You could be intolerant

If you react sensitively after eating certain foods, it’s probably because you can’t tolerate certain components of these foods. Some people can’t cope with lactose, while others find fructose problematic and others have to avoid gluten. Unlike an allergy – where symptoms are triggered by a misguided immune system – intolerances have other causes.

Whether a reaction is triggered by gluten is all down to a person’s genetic make-up as well as environmental factors. Both of these have an impact on the integrity of the intestinal mucosa – the innermost layer of the digestive tract. If this is fragile and “leaky”, unpleasant reactions to wheat can take place. How much gluten is needed to cause trouble varies from person to person and also changes throughout life.