From FARE (Food Allergy Research and Education):
“What is Food Allergy?
The job of the body’s immune system is to identify and destroy germs (such as bacteria or viruses) that make you sick. A food allergy results when the immune system mistakenly targets a harmless food protein – an allergen – as a threat and attacks it.”
(Accessed March 17, 2014; http://www.foodallergy.org/about-food-allergy )
From the Mayo Clinic:
Food allergy is an immune system reaction that occurs soon after eating a certain food. Even a tiny amount of the allergy-causing food can trigger signs and symptoms such as digestive problems, hives or swollen airways. In some people, a food allergy can cause severe symptoms or even a life-threatening reaction known as anaphylaxis.
Food allergy affects an estimated 6 to 8 percent of children under age 3 and up to 3 percent of adults. While there’s no cure, some children outgrow their food allergy as they get older.
It’s easy to confuse a food allergy with a much more common reaction known as food intolerance. While bothersome, food intolerance is a less serious condition that does not involve the immune system.”
(Accessed March 17, 2014; http://www.mayoclinic.org/diseases-conditions/food-allergy/basics/definition/con-20019293 )