Milk, nuts, eggs

Nutrition & Health Info Sheets for Consumers - Food Allergies

Nutrition & Health Info Sheets contain up-to-date information about nutrition, health, and food. They are provided in two different formats for consumer and professional users. These resources are produced by Dr. Rachel Scherr and her research staff. Produced by Savannah Boyd, Alyssa K. Allen, McKenzie Richard, Allison J. Boyer, Britt Loofbourrow, PhD Candidate, Anna M. Jones, PhD, and Rachel E. Scherr, PhD.

What are food allergies?

Food allergies are a response from the immune system that happens when certain foods, called allergens, are eaten [1]. After eating the food, an allergic reaction occurs with symptoms ranging from stomach pain to anaphylaxis. Anaphylaxis causes the airways to narrow, which makes breathing difficult, blood pressure to drop, and the body to go into shock. It can be fatal. The severity of the reaction depends on the person and how much of the allergen was eaten [2].

The most common types of food allergies are called “The Big Eight.” They include: peanuts, milk, eggs, soy, wheat, tree nuts, fish and shellfish [1-3]. These foods make up 90% of the food allergies in the US. Because of this, a law was passed, known as the Food Allergen Labeling and Consumer Protections Act of 2004. This law requires these allergens to be listed on food labels [2]. Sesame was added to the major allergen list when the Food Allergy Safety, Treatment, Education, and Research (FASTER) Act was signed into law in 2021. Beginning in 2023, sesame will also be included in food labels as an allergen [2].

How common are food allergies?

According to the World Allergy Organization, the rates of food allergies continue to increase throughout the world [4]. About 10 percent of people in developed countries have one or more food allergies [1].

The rate of peanut allergies has doubled from 2002 and 2012 in Western countries [4].

Studies show differences amongst racial groups and allergy risks. African Americans have shown a higher risk for shellfish allergies when compared to non-white ethnic groups [5]. Also, Caucasians have the highest diagnosed allergy rates, while Asian Americans have the lowest reported risk [6].

How are food allergies developed?

Genetic factors influence the risk of developing a food allergy. A child has a 75% chance of having a food allergy if both parents have one. If neither parent has a food allergy, there is only a 10% chance [7]. Early exposures to food play a crucial role in one’s future immune response to common food allergens. Early infections change the micro-organisms that live in the gut, which may change how the immune system responds [8-10]. Additionally, low vitamin D levels results in a higher risk for an immune response to foods. Also, there are lower rates of reported food allergies in places close to the equator [11].

What is the difference between allergies, sensitivities and intolerances?

Food allergies and food sensitivities or intolerances are quite different. “Allergy” refers to a specific type of immune response that occurs when a food is eaten. A food sensitivity or intolerance, however, is a person’s inability to digest the food normally [12]. Many of the same symptoms may occur here, but food allergies are often more dangerous as they involve more than one organ system.

To test if you have a food allergy or not, you can see your doctor to take one of three tests: the skin prick test, a blood test, or the doctor-supervised oral food test [13].

What are the health implications?

Food allergies affect 15 million people in the United States and cost up to 24.8 billion dollars each year. Peanuts are the leading cause of death from allergic reactions [14]. The extent of the allergic reaction depends on the amount of allergen that is eaten, parts of the body that are affected, and the amount of time since the previous exposure. Symptoms of an allergic reaction are nausea, vomiting, diarrhea, asthma, itching, edema (swelling), hives, and sometimes death [2,3].

How are food allergies treated and managed?

There is no cure for food allergies, so the goal is to reduce the severity and frequency of symptoms, while reducing future reactions [2]. This is done by staying away from foods that may cause a reaction or by using medicine. Some medications used for mild allergies are Benadryl (diphenhydramine) and Zyrtec (certirizine HCl), which can help with runny noses, headaches, and rashes. For worse symptoms, steroids can be used [15]. In the event of anaphylaxis, 911 should be called and epinephrine autoinjector medications like EpiPen and Auvi-Q should be used, if prescribed by a doctor [3,15].

Desensitization can also be used if it is overseen by a doctor. This is where small amounts of the trigger food are slowly added to the diet until a reaction no longer occurs. This is done in a controlled environment, such as a clinic or hospital. This creates a slight increase in the amount of a food the person can tolerate [15].

What are the recommendations for introducing foods to infants?

The American Academy of Pediatrics advises that infants are first introduced to solid foods between four and six months of age [16,17]. Before 17 weeks, solid foods are known to increase the risk of developing allergies [18]. It was originally believed that highly allergic foods should not be introduced until 12 months. Recently the American Academy of Allergy, Asthma, and Immunology said that waiting to introduce these foods may increase the risk of allergies [5,19]. This group recommend introducing foods that cause allergies very slowly once the baby is accepting other food well.


  1. Ho, M. H.-K.; Wong, W. H.-S.; Chang, C. Clinical Spectrum of Food Allergies: A Comprehensive Review. Clin. Rev. Allergy Immunol. 2014, 46 (3), 225–240.
  2. Nutrition, C. for F. S. and A. Food Allergies
  3. Philadelphia, T. C. H. of. IgE-Mediated Food Allergies
  4. Prescott, S. L.; Pawankar, R.; Allen, K. J.; Campbell, D. E.; Sinn, J. K.; Fiocchi, A.; Ebisawa, M.; Sampson, H. A.; Beyer, K.; Lee, B.-W. A Global Survey of Changing Patterns of Food Allergy Burden in Children. World Allergy Organ. J. 2013, 6 (1), 21.
  5. Sicherer, S. H.; Sampson, H. A. Food Allergy: Epidemiology, Pathogenesis, Diagnosis, and Treatment. J. Allergy Clin. Immunol. 2014, 133 (2), 291–307; quiz 308.
  6. Gupta, R. S.; Springston, E. E.; Warrier, M. R.; Smith, B.; Kumar, R.; Pongracic, J.; Holl, J. L. The Prevalence, Severity, and Distribution of Childhood Food Allergy in the United States. Pediatrics 2011, 128 (1), e9-17.
  7. Sicherer, S. H.; Furlong, T. J.; Maes, H. H.; Desnick, R. J.; Sampson, H. A.; Gelb, B. D. Genetics of Peanut Allergy: A Twin Study. J. Allergy Clin. Immunol. 2000, 106 (1), 53–56.
  8. Johnston, L. K.; Chien, K. B.; Bryce, P. J. The Immunology of Food Allergy. J. Immunol. Baltim. Md 1950 2014, 192 (6), 2529–2534.
  9. Rachid, R.; Chatila, T. A. The Role of the Gut Microbiota in Food Allergy. Curr. Opin. Pediatr. 2016, 28 (6), 748–753.
  10. Nowak-Wegrzyn, A.; Szajewska, H.; Lack, G. Food Allergy and the Gut. Nat. Rev. Gastroenterol. Hepatol. 2017, 14 (4), 241–257.
  11. Osborne, N. J.; Ukoumunne, O. C.; Wake, M.; Allen, K. J. Prevalence of Eczema and Food Allergy Is Associated with Latitude in Australia. J. Allergy Clin. Immunol. 2012, 129 (3), 865–867.
  12. Food allergy vs. food intolerance: What’s the difference?
  13. What Food Allergy Tests Mean
  14. Gupta, R.; Holdford, D.; Bilaver, L.; Dyer, A.; Holl, J. L.; Meltzer, D. The Economic Impact of Childhood Food Allergy in the United States. JAMA Pediatr. 2013, 167 (11), 1026–1031.
  15. Recognizing and Treating Reaction Symptoms | Food Allergy Research & Education
  16. Infant Food and Feeding
  17. Starting Solid Foods
  18. Grimshaw, K. E. C.; Maskell, J.; Oliver, E. M.; Morris, R. C. G.; Foote, K. D.; Mills, E. N. C.; Roberts, G.; Margetts, B. M. Introduction of Complementary Foods and the Relationship to Food Allergy. Pediatrics 2013, 132 (6), e1529-1538.
  19. Fleischer, D. M.; Spergel, J. M.; Assa’ad, A. H.; Pongracic, J. A. Primary Prevention of Allergic Disease Through Nutritional Interventions. J. Allergy Clin. Immunol. Pract. 2013, 1 (1), 29–36.

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