Up to two million, or 8% of children in the United States are estimated to be affected by food allergy, and up to 2% of adults have food allergies.  With a true food allergy, an individual’s immune system will overact to an ordinarily harmless food. Food allergy often may appear in someone who has family members with allergies and symptoms may occur after that allergic individual consumes even a tiny amount of food.

Food intolerance is sometimes confused with food allergy.  Food intolerance refers to an abnormal response to a food or food additive that is not an allergic reaction. It differs from an allergy in that it does not involve the immune system.  For instance, an individual may have uncomfortable abdominal symptoms after consuming mild.  This reaction is most likely caused by a milk sugar (lactose) intolerance, in which the individual lacks the enzymes to break down milk sugar for proper digestion.

Food allergens – those parts of foods that cause allergic reactions – are usually proteins.  Most of these allergens can still cause reactions even after they are cooked or have undergone digestion in the intestines.  Numerous food proteins have been studied to establish allergen content.

The most common food allergens – responsible for up to 90% of all allergic reactions-are the proteins in cow’s mild, eggs, peanuts, wheat, soy, fish, shellfish and tree nuts.