What constitutes a food allergy?

A food allergy is defined as an abnormal immune response to a protein found in food. When someone has a food allergy, their immune system mistakenly identifies a harmless food protein as a threat. This misidentification leads to the release of chemicals, such as histamine, which can cause a range of symptoms that may affect the skin, respiratory system, gastrointestinal tract, and cardiovascular system.

The other options do not accurately describe what a food allergy is. An unpleasant digestive reaction to food may indicate a food intolerance rather than an allergy, which typically involves the immune system. An intense dislike of foods is more about personal preferences and does not involve the immune system at all. Difficulty in digesting certain types of food can also relate to food intolerance or digestive disorders, rather than being an immune response, which is the hallmark of a true food allergy. Therefore, the correct answer effectively captures the essence of what a food allergy entails.