A food allergy is the body’s exaggerated reaction to a protein it thinks is harmful. Perceiving an attack, the immune system produces specific antibodies to destroy the allergy-producing substances, called allergens, says Associate Professor Scott Sicherer of the Jaffe Food Allergy Institute at the Mount Sinai School of Medicine. Whenever that food is ingested, the body releases chemicals (such as histamines) to protect itself. Symptoms of an allergy attack include rashes, hives, and nausea; in more severe cases, an allergy attack can lead to death.
Meat allergies are very unusual, and, as a result, aren’t studied as much or understood as well as more common food allergies such as those to peanuts, dairy, or shellfish, says Professor Steve Taylor, director of the Food Allergy Research and Resource Program at the University of Nebraska–Lincoln. Out of all meats, beef seems to be the one that causes more people to have allergic reactions.
The major beef allergen is called bovine serum albumin (BSA), a naturally occurring protein found in the blood of cattle. But BSA can be rendered harmless by the application of heat, so most people with a beef allergy react only to undercooked beef and have no problems eating a well-done steak, for instance. Similar albumin proteins found in pork, lamb, and chicken also seem to cause allergic reactions, but are different enough that a person with a chicken allergy may tolerate beef, and vice versa. There may be cases of cross-allergy, but they’re not well studied, says Taylor.
Low levels of these albumin proteins are also found in milk and egg yolks, so people with meat allergies are encouraged to consume only pasteurized dairy products and to make sure their eggs are thoroughly cooked.
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