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Food Allergy Causes

An allergic reaction occurs when the body's immune system overreacts to an allergen, in this case a food protein.

• The white blood cells produce an antibody to this allergen, called immunoglobulin E or IgE.
  • When this antibody comes in contact with the particular food protein, it promotes production and release of certain chemicals called "mediators." Histamine is an example of a mediator.
  • These mediators act on various parts of the body, mainly the skin, throat, airways, intestines, and heart.
  • The effects of the mediators on organs and other cells cause the symptoms of the allergic reaction.

• Any food has the potential to trigger an allergic reaction, but a few foods account for most food allergies. In fact, about 90% of food allergies are triggered by one of these 8 foods:
  • Eggs
  • Milk
  • Wheat
  • Soy
  • Peanuts
  • Tree nuts
  • Fish
  • Shellfish

• Generally, people who have allergies react to only a few foods. Occasionally a person who is allergic to one food also may be allergic to other related foods. This is called cross-reaction. Common examples:
  • Allergy to peanuts - Cross-allergies to soybeans, green beans, and peas
  • Allergy to wheat - Cross-allergy to rye
  • Allergy to cow's milk - Cross-allergy to goat's milk
  • Allergy to pollen - Cross-allergies to foods such as hazelnuts, green apples, peaches, and almonds

• People who have a history of other allergies, such as eczema or asthma, are particularly prone to having a reaction to a food. They are also more likely to have a more severe reaction.