Food allergies and food intolerances are two totally different reactions in the body. A food allergy is an overreaction of the immune system to a certain protein in our food, such as cow’s milk protein or soya protein. It occurs because the immune system believes the allergenic food is harmful, so it mounts an attack which leads to allergic symptoms like swelling, wheezing, itching, bloating, or diarrhoea. This reaction is reproducible, which means that it happens every time when certain foods are consumed.
When talking of food intolerance we mean any kind of negative reaction to a certain food or food additive that our body is unable to deal with. There can be lots of reasons for this, such as monosodium glutamate, histamine, enzyme deficiencies, or an irritable bowel. Food intolerance, as opposed to food allergy, does not involve the immune system. Reactions to food intolerances vary from one person to the next and heavily depend on the amount of food eaten, on how it was prepared and the individual condition of the affected person.