Soy allergy

Soy allergy

Soy allergy is a type of food allergy. It is a hypersensitivity to dietary substances from soy causing an overreaction of the immune system which may lead to severe physical symptoms for millions of people.[1] The Asthma and Allergy Foundation of America estimates soy is among the eight most common food allergens for pediatric and adult food allergy patients.[2] It is usually treated with an exclusion diet and vigilant avoidance of foods that may be contaminated with soy ingredients. The most severe food allergy reaction is called anaphylaxis[3] and is a medical emergency requiring immediate attention and treatment with epinephrine.

Signs and symptoms

Food allergies can have fast onset (from seconds to one hour) or slow onset (from hours to several days) depending on mechanism. Symptoms may include: rash, hives, itching of mouth, lips, tongue, throat, eyes, skin, or other areas, swelling of lips, tongue, eyelids, or the whole face, difficulty swallowing, runny or congested nose, hoarse voice, wheezing, shortness of breath, diarrhea, abdominal pain, lightheadedness, fainting, nausea and vomiting. Symptoms of allergies vary from person to person and may vary from incident to incident.[4] Serious danger regarding allergies can begin when the respiratory tract or blood circulation is affected. The former can be indicated by wheezing, a blocked airway and cyanosis, the latter by weak pulse, pale skin, and fainting. When these symptoms occur the allergic reaction is called anaphylaxis.[4] Anaphylaxis occurs when IgE antibodies are involved, and areas of the body that are not in direct contact with the food become affected and show severe symptoms.[4][5] Untreated, this can proceed to vasodilation, a low blood pressure situation called anaphylactic shock, and death (very rare).[5][6]

Non-IgE mediated reactions are slower to appear, and tend to manifest as gastrointestinal symptoms, without cutaneous or respiratory symptoms.[7][8] Within non-IgE reactions, clinicians distinguish among food protein-induced enterocolitis syndrome (FPIES), food protein-induced allergic proctocolitis (FPIAP) and food protein-induced enteropathy (FPE). Common trigger foods for all are soy infant formula, and also cow's milk formula.[8][9] FPIAP is considered to be at the milder end of the spectrum, and is characterized by intermittent bloody stools. FPE is identified by chronic diarrhea which will resolve when the offending food is removed from the infant's diet. FPIES can be severe, characterized by persistent vomiting 1-4 hours after an allergen-containing food, to the point of lethargy. Watery and sometimes bloody diarrhea can develop 5-10 hours after the triggering meal, to the point of dehydration and low blood pressure. Infants reacting to soy formula may also react to cow's milk formula.[9][10] International consensus guidelines have been established for the diagnosis and treatment of FPIES.[10]

Cause

Sources of soy protein

Many fast-food restaurants commonly use soy protein in hamburger buns (soy flour), hamburger meat (soy protein) and hydrolyzed vegetable protein (HVP) in sauces. On their respective websites, McDonald's and Burger King list soy flour as an ingredient in their hamburger buns.[11][12] U.S. Nutrition Information Multi-grain breads, doughnuts, doughnut mix and pancake mix commonly contain soy flour. Nearly all bread products available in the US now contain soy. Soy can now be found in nearly all types of foods, from meat to ice cream, to cheese, to french fries. Many foods are contaminated with soy due to being cooked in soy oil. At the Jack in the Box fast food chain for example, everything fried is cooked in a soy oil. At Baskin Robbins, over half of all ice creams offered contain soy. Canned tuna may contain vegetable broth which contains soy protein. Some products [for reasons having to do with national regulation of soy products] don't list soy protein or soy flour on their ingredients labels, yet they still contain soy.

Products containing soy protein include:

The following food additives may contain soy protein:

Cross-reactivity with dairy

Infants - either still 100% breastfeeding or partially/entirely on infant formula - and also young children - may be prone to a combined cow's milk and soy protein allergy referred to as "milk soy protein intolerance" (MSPI). A U.S. state government website presents the concept, including a recommendation that nursing mothers discontinue eating any foods that contain dairy or soy ingredients.[15] In opposition to this recommendation, a published scientific review stated that there was not yet sufficient evidence in the human trial literature to conclude that maternal dietary food avoidance during lactation would prevent or treat allergic symptoms in breastfed infants.[16]

A review presented information on soy allergy, milk allergy and cross reactivity between the two. Milk allergy was described as occurring in 2.2% to 2.8% of infants and declining with age. Soy allergy was described as occurring in zero to 0.7% of young children. According to several studies cited in the review, between 10% and 14% of infants and young children with confirmed cow's milk allergy were determined to also be sensitized to soy and in some instances have a clinical reaction after consuming a soy-containing food. The research did not address whether the cause was two separate allergies or a cross-reaction due to a similarity in protein structure, as which occurs for cow's milk and goat's milk.[17] Recommendations are that infants diagnosed as allergic to cow's milk infant formula be switched to an extensively hydrolyzed protein formula rather than a soy whole protein formula.[17][18]

Dosage tolerance

Many people with soy allergy can tolerate small or moderate amounts of soy protein: the typical dose needed to induce an allergic response is about 100 times higher than for many other food allergens.[19]

Mechanisms

Conditions caused by food allergies are classified into three groups according to the mechanism of the allergic response:[20]

  1. IgE-mediated (classic) – the most common type, manifesting acute changes that occur shortly after eating, and may progress to anaphylaxis
  2. Non-IgE mediated – characterized by an immune response not involving immunoglobulin E; may occur hours to days after eating, complicating diagnosis
  3. IgE and non-IgE-mediated – a hybrid of the above two types

Allergic reactions are hyperactive responses of the immune system to generally innocuous substances, such as proteins in the foods we eat. Why some proteins trigger allergic reactions while others do is not entirely clear, although in part thought to be due to resistance to digestion. Because of this, intact or largely intact proteins reach the small intestine, which has a large presence of white blood cells involved in immune reactions.[21] The heat of cooking structurally degrades protein molecules, potentially making them less allergenic.[22] Allergic responses can be divided into two phases: an acute response that occurs immediately after exposure to an allergen, which can then either subside or progress into a "late-phase reaction," prolonging the symptoms of a response and resulting in more tissue damage.

In the early stages of acute allergic reaction, lymphocytes previously sensitized to a specific protein or protein fraction react by quickly producing a particular type of antibody known as secreted IgE (sIgE), which circulates in the blood and binds to IgE-specific receptors on the surface of other kinds of immune cells called mast cells and basophils. Both of these are involved in the acute inflammatory response.[23] Activated mast cells and basophils undergo a process called degranulation, during which they release histamine and other inflammatory chemical mediators called (cytokines, interleukins, leukotrienes, and prostaglandins) into the surrounding tissue causing several systemic effects, such as vasodilation, mucous secretion, nerve stimulation, and smooth-muscle contraction. This results in runny nose, itchiness, shortness of breath, and potentially anaphylaxis. Depending on the individual, the allergen, and the mode of introduction, the symptoms can be system-wide (classical anaphylaxis), or localized to particular body systems; asthma is localized to the respiratory system while eczema is localized to the skin.[23]

After the chemical mediators of the acute response subside, late-phase responses can often occur due to the migration of other white blood cells such as neutrophils, lymphocytes, eosinophils, and macrophages to the initial reaction sites. This is usually seen 2–24 hours after the original reaction.[24] Cytokines from mast cells may also play a role in the persistence of long-term effects. Late-phase responses seen in asthma are slightly different from those seen in other allergic responses, although they are still caused by release of mediators from eosinophils.[25]

Diagnosis

Diagnosis of soy allergy is based on the person's history of allergic reactions, skin prick test (SPT), patch test and measurement of soy protein specific serum immunoglobulin E (IgE or sIgE). A negative IgE test does not rule out non-IgE mediated allergy, also described as cell-mediated allergy.[26] SPT and sIgE have sensitivities of 55% and 83% respectively, and specificities of 68% and 38%. These numbers mean that either test may miss diagnosing an existing soy allergy, and that both can also be positive for other food allergens.[27] Confirmation is by double-blind, placebo-controlled food challenges, conducted by an allergy specialist.[26]

Treatment

Treatment for accidental ingestion of soy products by allergic individuals varies depending on the sensitivity of the person. An antihistamine such as diphenhydramine (Benadryl) may be prescribed. Sometimes prednisone will be prescribed to prevent a possible late phase Type I hypersensitivity reaction.[28] Severe allergic reactions (anaphalaxis) may require treatment with an epinephrine pen, i.e., an injection device designed to be used by a non-healthcare professional when emergency treatment is warranted. A second dose is needed in 16-35% of episodes.[29]

Society and culture

Whether food allergy prevalence is increasing or not, food allergy awareness has definitely increased, with impacts on the quality of life for children, their parents and their immediate caregivers.[30][31][32][33] In the United States, the Food Allergen Labeling and Consumer Protection Act of 2004 causes people to be reminded of allergy problems every time they handle a food package, and restaurants have added allergen warnings to menus. Soy is one of the eight foods with mandatory labeling required. The Culinary Institute of America, a premier school for chef training, has courses in allergen-free cooking and a separate teaching kitchen.[34] School systems have protocols about what foods can be brought into the school. Despite all these precautions, people with serious allergies are aware that accidental exposure can easily occur at other peoples' houses, at school or in restaurants.[35] Food fear has a significant impact on quality of life.[32][33] Finally, for children with allergies, their quality of life is also affected by actions of their peers. There is an increased occurrence of bullying, which can include threats or acts of deliberately being touched with foods they need to avoid, also having their allergen-free food deliberately contaminated.[36]

Genetically modified food

There are concerns that genetically modified foods, also described as foods sourced from genetically modified organisms (GMO), could be responsible for allergic reactions, and that the widespread acceptance of GMO foods may be responsible for what is a real or perceived increase in the percentage of people with allergies.[37][38][39] One concern is that genetic engineering could make an allergy-provoking food more allergic, meaning that smaller portions would suffice to set off a reaction.[39] Of the food currently in widespread GMO use, only soy is identified as a common allergen. However, for the soybean proteins known to trigger allergic reactions, there is more variation from strain to strain than between those and the GMO varieties.[38] The same review quoted a 2016 U.S. National Academy of Sciences report that concluded, “The committee did not find a relationship between consumption of GE foods and the increase in prevalence of food allergies."[38]

A second concern is that genes transferred from on species to another could introduce an allergen in a food not thought of as particularly allergenic. Research on an attempt to enhance the quality of soybean protein by adding genes from Brazil nuts was terminated when human volunteers known to have tree nut allergy reacted to the modified soybeans.[37] At present, prior to a new GMO food receiving government approval, certain criteria need to be met. These include: Is the donor species known to be allergenic? Does the amino acid sequence of the transferred proteins resemble the sequence of known allergenic proteins? Will the transferred proteins be in the part of the plant to be eaten (as opposed to non-consumed roots, stems or leaves)? Are the transferred proteins resistant to digestion - a trait shared by many allergenic proteins?[38] Finally, there are requirements in some countries and recommendations in others that all foods containing GMO ingredients be so labeled, and that there be a post-launch monitoring system to report adverse effects (much there exists in some countries for drug and dietary supplement reporting).[37] According to a 2015 report from the Center for Food Safety, 64 countries require labeling of GMO products in the marketplace.[40]

See also

  • Allergy (has diagrams showing involvement of different types of white blood cells)
  • Food allergy (has images of hives, skin prick test and patch test)
  • List of allergens (food and non-food)

References

  1. ↑ National Institutes of Health, NIAID Allergy Statistics 2005 http://www.niaid.nih.gov/factsheets/allergystat.htm
  2. ↑ “Allergy Facts and Figures,” Asthma and Allergy Foundation of America http://www.aafa.org/display.cfm?id=9&sub=20&cont=518
  3. ↑ National Report of the Expert Panel on Food Allergy Research, NIH-NIAID 2003 "Archived copy" (PDF). Archived from the original (PDF) on 2006-10-04. Retrieved 2006-08-07.
  4. 1 2 3 MedlinePlus Encyclopedia Food allergy
  5. 1 2 Sicherer SH, Sampson HA (2014). "Food allergy: Epidemiology, pathogenesis, diagnosis, and treatment". J Allergy Clin Immunol. 133 (2): 291–307. doi:10.1016/j.jaci.2013.11.020. PMID 24388012.
  6. ↑ Urisu A, Ebisawa M, Ito K, Aihara Y, Ito S, Mayumi M, Kohno Y, Kondo N (2014). "Japanese Guideline for Food Allergy 2014". Allergol Int. 63 (3): 399–419. doi:10.2332/allergolint.14-RAI-0770. PMID 25178179.
  7. ↑ Koletzko S, Niggemann B, Arato A, Dias JA, Heuschkel R, Husby S; et al. (2012). "Diagnostic approach and management of cow's-milk protein allergy in infants and children: ESPGHAN GI Committee practical guidelines". J Pediatr Gastroenterol Nutr (Practice Guideline). 55 (2): 221–9. doi:10.1097/MPG.0b013e31825c9482. PMID 22569527.
  8. 1 2 Leonard SA (2017). "Non-IgE-mediated Adverse Food Reactions". Curr Allergy Asthma Rep (Review). 17 (12): 84. doi:10.1007/s11882-017-0744-8. PMID 29138990.
  9. 1 2 Caubet JC, Szajewska H, Shamir R, Nowak-Węgrzyn A (2017). "Non-IgE-mediated gastrointestinal food allergies in children". Pediatr Allergy Immunol. 28 (1): 6–17. doi:10.1111/pai.12659. PMID 27637372.
  10. 1 2 Nowak-Węgrzyn A, Chehade M, et al. (2017). "International consensus guidelines for the diagnosis and management of food protein-induced enterocolitis syndrome: Executive summary-Workgroup Report of the Adverse Reactions to Foods Committee, American Academy of Allergy, Asthma & Immunology". J. Allergy Clin. Immunol. 139 (4): 1111–1126.e4. doi:10.1016/j.jaci.2016.12.966. PMID 28167094.
  11. ↑ "McDonald's Nutrition Information and Ingredients" Archived 2008-03-24 at the Wayback Machine., August 26, 2006, retrieved September 7, 2006
  12. ↑ Burger King USA (11 page PDF file) "Burger King Nutrition and Ingredients" Burger King Brands Inc. USA, August, 2006, retrieved September 7, 2006
  13. ↑ Hidden Allergens in Foods, Allergy Advisor, retrieved 2011-12-27
  14. ↑ Staff, Cleveland Clinic. Soy Allergy
  15. ↑ Milk Soy Protein Intolerance (MSPI) Nebraska Department of Health and Human Services (2017).
  16. ↑ Kramer MS, Kakuma R (2014). "Maternal dietary antigen avoidance during pregnancy or lactation, or both, for preventing or treating atopic disease in the child". Evid Based Child Health. 9 (2): 447–83. doi:10.1002/ebch.1972. PMID 25404609.
  17. 1 2 Kattan JD, Cocco RR, Järvinen KM (2011). "Milk and soy allergy". Pediatr Clin North Am (Review). 58 (2): 407–26, x. doi:10.1016/j.pcl.2011.02.005. PMC 3070118. PMID 21453810.
  18. ↑ Bhatia J, Greer F (2008). "Use of soy protein-based formulas in infant feeding". Pediatrics. 121 (5): 1062–8. doi:10.1542/peds.2008-0564. PMID 18450914.
  19. ↑ Christopher T. Cordle (1 May 2004). "Soy Protein Allergy: Incidence and Relative Severity". Journal of Nutrition. 134 (5): 1213S–1219S. PMID 15113974.
  20. ↑ "Food allergy". NHS Choices. 16 May 2016. Retrieved 31 January 2017. A food allergy is when the body's immune system reacts unusually to specific foods
  21. ↑ Food Reactions. Allergies Archived 2010-04-16 at the Wayback Machine.. Foodreactions.org. Kent, England. 2005. Accessed 27 Apr 2010.
  22. ↑ Mayo Clinic. Causes of Food Allergies. Archived 2010-02-27 at the Wayback Machine. April 2010.
  23. 1 2 Janeway, Charles; Paul Travers; Mark Walport; Mark Shlomchik (2001). Immunobiology; Fifth Edition. New York and London: Garland Science. pp. e–book. ISBN 0-8153-4101-6. Archived from the original on 2009-06-28.
  24. ↑ Grimbaldeston MA, Metz M, Yu M, Tsai M, Galli SJ (2006). "Effector and potential immunoregulatory roles of mast cells in IgE-associated acquired immune responses". Curr. Opin. Immunol. 18 (6): 751–760. doi:10.1016/j.coi.2006.09.011. PMID 17011762.
  25. ↑ Holt PG, Sly PD (2007). "Th2 cytokines in the asthma late-phase response". Lancet. 370 (9596): 1396–1398. doi:10.1016/S0140-6736(07)61587-6. PMID 17950849.
  26. 1 2 National Institute of Allergy and Infectious Diseases (July 2012). "Food Allergy An Overview" (PDF). Archived from the original (pdf) on 2016-03-05.
  27. ↑ Soares-Weiser K, Takwoingi Y, Panesar SS, Muraro A, Werfel T, Hoffmann-Sommergruber K, Roberts G, Halken S, Poulsen L, van Ree R, Vlieg-Boerstra BJ, Sheikh A (2014). "The diagnosis of food allergy: a systematic review and meta-analysis". Allergy. 69 (1): 76–86. doi:10.1111/all.12333. PMID 24329961.
  28. ↑ Tang AW (2003). "A practical guide to anaphylaxis". Am Fam Physician. 68 (7): 1325–1332. PMID 14567487.
  29. ↑ The EAACI Food Allergy and Anaphylaxis Guidelines Group (August 2014). "Anaphylaxis: guidelines from the European Academy of Allergy and Clinical Immunology". Allergy. 69 (8): 1026–1045. doi:10.1111/all.12437. PMID 24909803.
  30. ↑ Ravid NL, Annunziato RA, Ambrose MA, Chuang K, Mullarkey C, Sicherer SH, Shemesh E, Cox AL (2015). "Mental health and quality-of-life concerns related to the burden of food allergy". Psychiatr. Clin. North Am. 38 (1): 77–89. doi:10.1016/j.psc.2014.11.004. PMID 25725570.
  31. ↑ Morou Z, Tatsioni A, Dimoliatis ID, Papadopoulos NG (2014). "Health-related quality of life in children with food allergy and their parents: a systematic review of the literature". J Investig Allergol Clin Immunol. 24 (6): 382–95. PMID 25668890.
  32. 1 2 Lange L (2014). "Quality of life in the setting of anaphylaxis and food allergy". Allergo J Int. 23 (7): 252–260. doi:10.1007/s40629-014-0029-x. PMC 4479473. PMID 26120535.
  33. 1 2 van der Velde JL, Dubois AE, Flokstra-de Blok BM (2013). "Food allergy and quality of life: what have we learned?". Curr Allergy Asthma Rep. 13 (6): 651–61. doi:10.1007/s11882-013-0391-7. PMID 24122150.
  34. ↑ Culinary Institute of America Allergen-free oasis comes to the CIA (2017)
  35. ↑ Shah E, Pongracic J (2008). "Food-induced anaphylaxis: who, what, why, and where?". Pediatr Ann. 37 (8): 536–41. PMID 18751571.
  36. ↑ Fong AT, Katelaris CH, Wainstein B (2017). "Bullying and quality of life in children and adolescents with food allergy". J Paediatr Child Health. 53 (7): 630–635. doi:10.1111/jpc.13570. PMID 28608485.
  37. 1 2 3 Lee TH, Ho HK, Leung TF (2017). "Genetically modified foods and allergy". Hong Kong Med J. 23 (3): 291–295. doi:10.12809/hkmj166189. PMID 28473652.
  38. 1 2 3 4 Dunn SE, Vicini JL, Glenn KC, Fleischer DM, Greenhawt MJ (2017). "The allergenicity of genetically modified foods from genetically engineered crops: A narrative and systematic review". Ann. Allergy Asthma Immunol. 119 (3): 214–222.e3. doi:10.1016/j.anai.2017.07.010. PMID 28890018.
  39. 1 2 Selb R, Wal JM, Moreno FJ, Lovik M, Mills C, Hoffmann-Sommergruber K, Fernandez A (2017). "Assessment of endogenous allergenicity of genetically modified plants exemplified by soybean - Where do we stand?". Food Chem. Toxicol. 101: 139–148. doi:10.1016/j.fct.2017.01.014. PMID 28111299.
  40. ↑ "International Labeling Laws". Center for Food Safety.


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