Causes and Risk Factors for Food Allergies

According to the World Health Organization (WHO), more than 70 foods have been identified as possible food allergy causes. In some cases, an allergic reaction occurs in response to a food that had been eaten previously without causing allergy symptoms.

Although just about any food can cause an allergic reaction, most food allergies are caused by the following:

  • Eggs
  • Fish
  • Milk
  • Peanuts (which are actually a legume and not a nut)
  • Shellfish (e.g., shrimp, crab, lobster)
  • Soy (e.g., soy milk, soybeans, tofu, miso)
  • Tree nuts (e.g., walnuts, almonds, pecans, cashews, Brazil nuts, macadamia nuts, pistachios, chestnuts, beechnuts, hazelnuts)
  • Wheat

In children, common causes for food allergies include milk, eggs, peanuts, fish, and tree nuts. Children who are allergic to milk or eggs may outgrow their allergy; however, other food allergies usually are not outgrown. In adults, shellfish, peanuts, tree nuts, fish, and eggs are responsible for most allergic reactions. The most common causes for severe food allergy are peanuts, tree nuts, and shellfish.

People who have seasonal allergies (e.g., hay fever) or eczema (dermatitis), and people with a family history of allergies or asthma are at increased risk for developing a food allergy. Also, people with an allergy to one food have a higher risk for other food allergies.

People with an allergy to, for example, tree pollen or latex, may experience a food allergy related to "cross-reactivity."In these people, an allergic reaction occurs from eating certain foods because the immune system cannot distinguish between allergens, such as pollen or latex, and related proteins in the food. People who have hay fever may have an allergic reaction when they eat fresh fruits (e.g., peaches, apples, pears, cherries), nuts (e.g., almonds), cucumbers, or sunflower seeds.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 20 Oct 2008

Last Modified: 26 Jul 2010