While only a small percentage of Americans suffer from food allergies, the symptoms can be mysterious because they affect all parts of the body. In addition, they can be downright dangerous. When someone with food allergies eats the offending food, the body reacts to the substance as if it were a threat and fights back by creating antibodies. The antibodies bind with mast cells. The next time the substance is eaten, these antibodies signal the mast cells to release histamine, which in turn causes symptoms.
Allergic reactions can happen from within minutes to a few hours after eating the offending food.
Common Food Allergens Common food allergens include milk, peanuts, eggs, fish, shellfish, soy, wheat, and tree nuts such as walnuts. Bad reactions to food, however, are not always caused by food allergies. Nonallergic reactions such as food poisoning or food intolerance may be the culprit. Skin-prick tests and, in some cases, special blood tests can help detect food allergies. Keeping a food diary and recording symptoms may also be helpful.