John Myers
The last bite is chewed – and off you go: redness, swelling, skin rashes or gastrointestinal complaints. Something the body doesn’t tolerate well. Is this an allergy now? Or an intolerance? Because: The complaints are similar.
The good news first: far fewer people have food allergies than previously thought. In surveys, around one in five thinks they suffer from a food allergy. However, only around three percent of adults are actually affected. The rate is about twice as high in children – fortunately, allergies often go away on their own in childhood. Depending on the trigger, however, allergies can be a lifelong companion: especially when tree nuts or fish are the culprits.
But not every diarrhea is caused by a food intolerance – and not every skin rash necessarily indicates an allergy.
Allergy
In the case of a real allergy, the immune system reacts excessively to a harmless substance, such as chicken protein, nuts or fish. A food allergy is triggered by the protein molecules in the food. Therefore, salt or sugar cannot cause allergic reactions.
In order for an allergy to develop, the body must first have had repeated contact with the allergen – the substance that triggers the allergy. This can happen, for example, via the skin or the respiratory tract. The immune system recognizes the substances. Sensitization is now taking place in some people. The body is ready.
As soon as the body has contact with the allergen again, it starts: The body deploys all its defense artillery and reacts as if the allergen were a dangerous virus or a particularly nasty bacterium. Various messenger substances such as histamine are released and cause an inflammatory reaction: for example reddening or swelling as the blood vessels become more permeable. Or the smooth muscles contract and cause shortness of breath in the airways or indigestion in the intestines.
Insidiously, the protein structures of pollen resemble the structures of some foods such as apples, nuts or celery. The result: the immune system reacts to these foods because it confuses the pollen with the food. In this case one speaks of a cross allergy.
In the case of an allergy, the reactions usually start relatively quickly, often after just a few seconds. It doesn’t matter whether we eat a good portion of the food in question – or just take a small bite. Because the smallest amounts are enough to activate the immune system.
Intolerance
In the case of an intolerance, the body reacts to certain foods with signs of illness – without the immune system being involved. An enzyme defect can be to blame, for example. For example, lactose intolerance lacks the enzyme lactase, which normally breaks down the lactose contained in milk into different types of sugar.
The result: the lactose rumbles from the small intestine into the large intestine, where it is broken down by the intestinal bacteria. And that has consequences: for example flatulence, abdominal pain or diarrhea. Allergy or intolerance – after all, only a doctor’s test can provide a reliable diagnosis.
