What is the difference between allergies and intolerances?
Allergies and intolerances are both types of adverse reactions to food. The major differences between them are the speed and the severity of that reaction. A classical allergy will cause an immediate reaction after contact with an allergen. You will generally know straight away if you are allergic to something, because the swiftness of the reaction allows you to identify the link between cause and effect. An intolerance or sensitivity, on the other hand, causes reactions that can occur between 1 hour and up to 48 hours later. So the reaction time is generally slower. Intolerances and sensitivities are much harder to identify if something you ate at lunchtime causes you to be tired in the afternoon, or a sandwich gives you a headache two days after you ate it because you have wheat intolerance, then you are unlikely to link the two events without careful and in-depth investigation.
