What is a potential consequence of consuming food contaminated with allergens?

Consuming food contaminated with allergens can lead to serious health reactions that may manifest as difficulty breathing, swelling, hives, and anaphylaxis, among other symptoms. These reactions occur because, in someone with a food allergy, the immune system mistakenly identifies a harmless protein in the food as a threat and mounts an aggressive response. This can involve the release of histamines and other chemicals that can significantly affect various bodily functions, particularly the respiratory system, leading to symptoms such as wheezing or difficulty in breathing.

In contrast, the other choices do not align with the health implications of allergen exposure. Permanent immunity is not achieved through exposure to allergens; rather, repeated exposure can sometimes lead to more severe reactions. A faster metabolism and a temporary increase in appetite are unrelated concepts and do not occur as direct consequences of consuming allergenic foods. Thus, serious health reactions, like difficulty breathing, clearly establish the dangers presented by food allergens.