What’s the difference between a food allergy and intolerance?
Food allergy
A food allergy is when the body’s immune system gets confused and over reacts to an allergen in food which is always a protein.
The immune system recognises the food allergen (food protein) as foreign and releases defence chemicals which cause an allergic reaction in one or more parts of the body (facial swelling, hives, vomiting, rashes, stomach pains, and diarrhoea). Symptoms reappear every time the food is consumed. Reactions may occur rapidly (within minutes or hours) or may be delayed (days). It is important to get a doctor to diagnose an allergy if you suspect one.
Intolerance
A food intolerance is a reproducible reaction to a non-protein food ingredient or ingredients which does not involve the immune system.
Food intolerance is often related to dose or frequency of exposure to the particular food. A reaction may not always occur with each exposure to the food or food additive, and the build up effect is highly variable.
Reactions may be immediate or delayed by up to 20 hours and can also be more general (headaches, bloating, wind) making diagnosis difficult.
Common intolerances include an enzyme deficiency (lactose intolerance caused by lactose deficiency) natural chemicals in foods e.g. salicylates, glutamates or compounds produced by the fermentation of food, i.e. amines.