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Module 1. Food Allergies in the United States

Learning Objectives

After the module, students will be able to:

  1. Define food allergies
  2. Discuss the prevalence and current trends of food allergies in the U.S.
  3. Identify the most common food allergens in the U.S.
  4. Identify other food allergens that affect individuals in different countries

Module Content

Definitions

Food

A food is defined as "any substance - whether processed, semi-processed, or raw - that is intended for human consumption, and includes drinks, chewing gum, food additives, and dietary supplements. Substances used only as drugs, tobacco products, and cosmetics (such as lip-care products) that may be ingested are not included" (Boyce et al., 2010, p. S8).

Food Allergy

A food allergy is defined as "an abnormal response to a food, triggered by the body's immune system" or "an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food" (Boyce et al., 2010, p. S8).

Food Allergen

Food allergens are defined as "those specific components of food or ingredients within food (typically proteins, but sometimes also chemicals) that are recognized by allergen-specific immune cells and elicit specific immunologic reactions, resulting in characteristic symptoms" (Boyce et al., 2010, p. S8).

Allergic Response

An allergic response is defined as "a reproducible adverse reaction to a substance mediated by an immunological response. The substances provoking the reaction may have been ingested, injected, inhaled, or merely have come into contact with the skin or mucous membranes" (David, 2000, p. 34).

Food Intolerance

Food intolerances are defined as non-immunologic adverse reactions to foods.

For example, lactose intolerant individuals cannot tolerate milk due to the inability to digest the sugar lactose. While milk protein is considered an allergen that triggers an adverse immunologic reaction, the inability to digest lactose leads to "excess fluid production in the gastrointestinal (GI) tracts, resulting in abdominal pain and diarrhea" (Boyce et al., 2010, p. S9).

Food intolerance is often caused by an enzyme defect.

  • Lactase deficiency: a reduced concentration or absence of lactase in small intestine mucosa causes the inability to breakdown lactose in one's diet.
  • Hereditary fructose intolerance: a deficiency in fructose bi-phosphate aldolase, a liver enzyme, causes the inability to digest the sugar fructose.

Food intolerance is also caused by pharmacological mechanisms, irritant mechanisms, specific drug-food combinations, toxic mechanisms, and food storage.

Immunoglobulin E (IgE)

Immunoglobulin E (IgE) is a unique class of immunoglobulin that mediates an immediate allergic reaction (Boyce et al., 2010).

IgE is released from plasma cells in the mucosa of the gastrointestinal tract, respiratory tract, and tonsils when the immune system overreacts to an allergen, triggering the release of histamine and inflammatory responses (Marieb & Hoehn, 2010).

Adverse Reaction to Food

Adverse reaction to food (Boyce et al., 2010)

  • Immune-mediated: food allergies
    • IgE-mediated (e.g., acute urticarial [hives], oral allergy syndrome)
    • Non-IgE-mediated (e.g., food protein-induced enteropathy)
    • Mixed IgE and mediated (e.g., eosinophilic gastroenteritis)
    • Cell-mediated (e.g., allergic contact dermatitis, celiac disease)
  • Non-immune-mediated (primarily food intolerances)
    • Metabolic (e.g., lactose intolerance)
    • Pharmacologic (e.g., caffeine)
    • Toxic (e.g., scombroid fish toxin)
    • Other/Idiopathic/Undefined (e.g., sulfites)

For more information about adverse reactions to food, see Module 2.

Food Allergy Research and Education (FARE)

Food Allergy Research and Education (FARE), is an organization "dedicated to food allergy research and education with the mission of ensuring the safety and inclusion of individuals with food allergies while relentlessly seeking a cure" (FARE, 2014).

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Types and prevalence of food allergies in the United States

The Big 8 is a list of the top eight allergens in the U.S.: eggs, milk, shellfish, wheat, peanuts, fish, soy and tree nuts (USDA, 2012).

Big 8 statistics

In the U.S., 90% of food allergies are caused by eggs, milk, shellfish, wheat, peanut, fish, soy and tree nuts (e.g., walnuts, cashews, almonds, pecans, pistachios, hazelnuts and macadamia nuts) (Sicherer, 2010).

The estimated prevalence of allergies among the U.S. population (Boyce et al., 2010):

  • Peanut: 0.6%-1.3%
  • Tree nuts: 0.4%-0.6%
  • Fish: 0.4%
  • Crustacean shellfish (crab, crayfish, lobster, shrimp): 1.2%
  • All seafood: 0.6% in children and 2.8% in adults
  • Milk and egg: 1%-2% for young children and 0.2%-0.4% in the general population

According to research conducted at a university referral hospital, most infants who had a milk allergy developed this condition before their first birthday, and about 80% of them developed tolerance before they were five years old. Of these children with milk allergies, nearly 35% of them had other food allergies (Boyce et al., 2010).

Food allergies among children

In 2007, about three million children under the age of 18 (3.9%) were reported to have a food allergy (Branum, 2008).

Reports of food allergies increased by 18% from 1997 to 2007 among children 18 years of age and younger (Branum, 2008).

From 2004 to 2006, children 18 years of age and younger represented approximately 9,500 hospital discharges per year from a diagnosis related to a food allergy (Branum, 2008).

It is more common for female than male adults to have food allergies, while male children typically have more food allergies than female children (Ben-Shoshan, Turnbull, & Clarke, 2012).

Figure 1.1 graph
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Figure 1.1. Percentage of children under 18 years of age who reported a food or digestive allergy in the past 12 months, by age, sex, race and ethnic group in the United States, 2007. Adapted from "Food allergy among U.S. children: Trends in prevalence and hospitalizations," by A. M. Branum, and S. L. Lukacs, 2008, HCHS Data Brief, 10, p.1. Copyright 2008 by the U.S. Department of Health & Human Services.

Emerging and less prevalent allergens

The majority of studies have focused on the most common food allergens, even though more than 170 foods have been reported to cause IgE-mediated reactions (Boyce et al., 2010).

Uncommon allergens include the following (FARE, 2014):

  • Corn: raw and cooked
  • Meat: beef, mutton, chicken and pork (heating and cooking meat may reduce allergenicity
  • Gelatin: a protein formed when connective tissue or skin is boiled
  • Seeds: sesame, poppy, or sunflower
  • Spices: coriander, mustard and garlic

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Types and prevalence of food allergies in foreign countries

For many individuals, food allergies depend on their geographical location and tend to be staple foods eaten on a regular basis rather than foods eaten sporadically.

Common allergens in other countries and regions (Baumert, 2012):

  • Canada: sesame, mollusks, mustard, sulfites, and gluten
  • Europe: sesame, mollusks, sulfites, gluten, mustard, celery, and lupin (a type of legume used in flour form)
  • Codex (South Africa): gluten and sulfites
  • Hong Kong: sulfites and gluten
  • Japan: milk, egg, peanuts, and wheat
  • Australia/New Zealand: sesame, mollusks, sulfites, and gluten

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Impact of food allergies

Hospitalization related to food allergies

Figure 1.2, graph
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Figure 1.2. Percentage of children under 18 years of age who reported a food or digestive allergy in the past 12 months, by age, sex, race and ethnic group in the United States, 1998-2006. Adapted from "Food Allergy Among U.S. Children: Trends in Prevalence and Hospitalizations," by A. M. Branum, and S. L. Lukacs, 2008. Copyright 2008 by the U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics.

Between 2001 and 2006, 31 fatalities due to food-induced anaphylaxis occurred. Eight of these fatalities occurred in restaurants. (Bock et al., 2007)

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Video case study for class discussion

Peanut allergy causes parents' outrage

Includes controversial viewpoints about provisions for children with food allergies in schools.

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Additional information

Hypotheses for an apparent increase in food allergy prevalence:

Ben-Shoshan, M., Turnbull, E., & Clarke, A. (2012). Food allergy: Temporal trends and determinants. Current Allergy and Asthma Reports, 12, 346-372.

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References

Baumert, J. (2012, October). Food Allergies. Symposium conducted at the annual meeting of Academy of Nutrition and Dietetics, Food & Nutrition Conference & Expo, Philadelphia, PA.

Ben-Shoshan, M., Turnbull, E., & Clarke, A. (2012). Food allergy: Temporal trends and determinants. Current Allergy and Asthma Reports, 12, 346-372.

Bock, S. A., Muñoz-Furlong, A., & Sampson, H.A. (2007). Further fatalities by anaphylactic reactions to food, 2001-2006. Journal of Allergy and Clinical Immunology, 119, 1016-1018.

Borchgrevink, C. P., Elsworth, J. D., Taylor, S. E., & Christensen, K. L. (2010). Food intolerances, food allergies, and restaurants. Journal of Culinary Science & Technology, 7, 259-284.

Boyce, J. A., Assa'ad, A., Burks, A. W., Jones, S. M., Sampson, H. A., Wood, R. A., ... Schwaninger, J. M. (2010). Guidelines for the diagnosis and management of food allergy in the United States: Report of the NIAID-sponsored expert panel. The Journal of Allergy and Clinical Immunology, 126(6), S1-S58.

Branum, A. M., & Lukacs, S. (2008). Food allergy among US children: Trends in prevalence and hospitalizations. US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics.

Colver, A. (2006). For and against: Are the dangers of childhood food allergy exaggerated? British Medical Journal, 333, 494-498.

David, T. J. (2000). Adverse reactions and intolerance to foods. British Medial Bulletin. 56(1), 34-50.

Food Allergy Research and Education. (2014). Food allergy facts and statistics for the U.S. Retrieved from http://www.foodallergy.org/facts-and-stats

Nguyen‐Luu, N. U., Ben‐Shoshan, M., Alizadehfar, R., Joseph, L., Harada, L., Allen, M., . . . Clarke, A. (2012). Inadvertent exposures in children with peanut allergy. Pediatric Allergy and Immunology, 23, 134-140.

Sicherer, S. H., & Sampson, H. A. (2010). Food allergy. Journal of Allergy and Clinical Immunology, 125(2), S116-S125.

U.S. Food and Drug Administration. (2012). Food allergies: What you need to know. Retrieved from http://www.fda.gov/downloads/Food/ResourcesForYou/Consumers/UCM220117.pdf

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