Food allergies occur when the immune system identifies the proteins in a particular food as harmful to the body, subsequently reacting to try to "fight off" the "harmful" proteins (which are in fact harmless). About 12 million Americans have food allergies: roughly six percent of children and two percent of adults in the United States.
The "big eight" are the eight most common foods that cause allergies. The following eight foods cause about 90 percent of all food allergies: cow's milk, eggs, fish, peanuts, tree nuts (including almonds, Brazil nuts, hazelnuts and walnuts), shellfish (including crab, mussels and shrimp), soy and wheat.
Children are most likely to be allergic to milk, eggs, tree and ground nuts, soy and wheat, while adults are most likely to be allergic to fish, shellfish, nuts, citrus fruits and wheat. Food allergies are not always permanent and many children grow out of them as they get older. About two-thirds of children who are allergic to eggs will outgrow the allergy by the time they are three years old. About 80 percent of children with wheat or soy allergies will outgrow them by the time they are five, and the same percentage of children with a milk allergy will outgrow it by the time they reach adulthood. Nut allergies are rarely outgrown, with only about 20 percent of children outgrowing peanut allergies and about nine percent outgrowing tree nut allergies. If you develop a food allergy later in life it's unlikely that you will outgrow it.
When you are allergic to a food, make sure to read food labels carefully to ascertain whether there might be traces of the allergen in the product. See an allergist if you suspect you may have a food allergy. If you do, you will have to stop eating the allergen and may have to avoid coming into contact with it at all, depending on the severity of your allergy. You may need to carry epinephrine with you so you can treat yourself immediately in case of a severe reaction.