When someone with coeliac disease eats gluten, a protein in wheat, barley and rye, the immune system reacts by attacking the lining of the small intestine.A large proportion of the Western diet contains gluten, from bread, pasta, pizza and cakes to products such as mayonnaise, soy sauce, sauces, sausages and many processed foods.About one in every 100 people in the UK has coeliac disease but only