Colorado State University Extension
SafeFood Rapid Response Network
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Food Allergy or Intolerance?
Edited by: Stephanie Wallner, M.S., Mary Schroeder, M.S., R.D, Pat Kendall, Ph.D., R.D., Colorado State - Fall 2006
If you experience an unpleasant reaction, such as hives, nausea or diarrhea, when you eat certain foods, you may have a food allergy. Then again, it may be a food intolerance. Either way, your best response is often to avoid the offending food in the future.
Food allergies
If you have a true food allergy, your immune system is unusually sensitive to a protein contained in particular foods. When a food containing the protein is eaten, the immune system produces antibodies to attack what it considers a foreign and harmful substance. This reaction triggers the release of histamines and a chain of reactions which result in uncomfortable, sometimes life-threatening, symptoms affecting the skin, the respiratory and gastrointestinal tracts, or even the cardiovascular system.
True allergic reactions to foods are rare, but can be quite severe, and include tingling in the mouth, swelling of the tongue or throat, shortness of breath or difficulty breathing, nausea, vomiting, diarrhea, hives, dangerously low blood pressure, and unconsciousness. In fact, an estimated 150 persons in the U.S. die each year from a severe food allergic reaction. The symptoms of an allergic reaction appear quickly, usually within two hours after the offending food is consumed.
For adults with food allergies, the most common triggers are shellfish such as shrimp and lobster, peanuts, tree nuts, fish, and eggs. Reactions in children are most often caused by eggs, milk, soy, and peanuts. Children may outgrow certain food allergies, but those that first appear in adulthood usually remain for life. In addition, true allergies to peanuts, tree nuts, fish, and shellfish are usually life-long for both children and adults.
Food intolerances
If the adverse reaction to food doesn't involve the body's immune system, but rather is the result of the body's inability to digest certain foods or components of foods, it is called a food intolerance. Lactose intolerance is a common type of food intolerance. Individuals with this condition cannot properly digest milk due to the body's deficiency of an enzyme called lactase, which breaks down the sugar in milk. If a lactose-containing substance such as milk is consumed, cramps and diarrhea result. For some, the reaction occurs with any amount of the offending food. Others can enjoy small amounts of lactose-containing foods, but have trouble digesting a full glass of milk or bowl of ice cream, for example.
Dealing with a food allergy or intolerance:
Currently, there are no cures for food allergies or intolerances. There are digestive aids that can help with intolerances to the sugars in milk and beans. For annoying, but not severe food allergy symptoms, your doctor may prescribe an antihistamine. For severe reactions, an injection of epinephrine (adrenaline) may be necessary. People prone to severe reactions to food are advised to wear an alert bracelet or necklace.
Once a food allergy or intolerance is diagnosed, the following steps can help prevent an adverse reaction:
- Consult with your health care professional or a registered dietitian to learn how to manage your food allergy or intolerance.
- Always know what you are eating and drinking. Read food labels carefully.
- Learn the common ingredient terms for the offending substance. For example, if you are allergic to eggs, avoid foods that list albumin and globulin in the ingredient list.
- When eating out, ask about ingredients and preparation methods of menu items before ordering.
More information on food allergies and intolerances is available at the following websites:
