Food allergy

Classification according to ICD-10
K52.2	Allergic and alimentary gastroenteritis and colitis -Gastroenteritis or colitis due to food allergy
L27.2	Dermatitis from ingested foods
T78.0	Anaphylactic shock from food intolerance
ICD-10 online (WHO version 2019)

The food allergy or food allergy is a specific form of food intolerance . It is characterized by a specific hypersensitivity ( allergy ) to certain substances that are contained in food and are ingested with it.

Symptoms and ailments

The extent of the allergic reaction can vary greatly from person to person. Food allergies manifest themselves in reactions of the mucous membrane , for example in the form of swelling of the mucous membrane in the entire mouth, nose ( allergic rhinitis ) and throat and swelling of the tongue. Symptoms in the stomach - intestinal region are for. B. nausea , vomiting , gas and diarrhea . Food allergies can, however, also lead to reactions of the airways with constriction of the bronchi (allergic asthma ) and the skin ( atopic eczema , itching and hives ). In extreme cases, life-threatening anaphylactic shock can occur.

Food allergies in infancy and young children

Infants and young children with food allergies in particular can suffer from severe vomiting and diarrhea, which can subsequently also impair normal development (growth in height, weight gain). Typical food allergies in infancy and young children are allergies to milk, eggs, meat, fish, nuts and, to an increasing extent, soy . In the case of strong sensitizations , allergic reactions to breast milk also occur, which can contain all allergens from those foods that the mother ingests.

According to a study, food allergens such as milk components, hazelnuts, seafood , ovalbumin or fish allergens are completely digested in vitro by simulating acidic gastric digestion with pepsin , but not when the pH value is increased. From this, the researchers concluded that food allergy problems could be related to an increased pH environment in the stomach. Infants only have gastric acid levels like adults at the end of their second year of life. People with reduced gastric acid secretion or who have taken antacids , sucralfate , H ₂ -receptor blockers or proton pump inhibitors also have elevated gastric pH values.

The optimal nutrition for newborns is exclusive breastfeeding for at least the first four months of life, whereby it should be noted that cow's milk allergens and egg allergens [and others?] Are transmitted through breast milk and the breastfeeding mother then also avoids these high-risk foods should. Additional feeding should be started at the latest from the sixth month of life. There are a number of special products for feeding babies and young children who either cannot be breastfed and have an increased risk of allergies or who suffer from food allergies. Hypoallergenic Formula Food (or HA Food) consists of highly hydrolyzed whey or whole milk proteins . Here all proteins are only very small fragments before that of IgE - antibodies can not be detected and therefore no allergic reactions can trigger more. One disadvantage of hydrolyzed baby foods is their very bitter taste. Baby foods based on soy proteins or rice proteins offer the option of avoiding cow's milk . Soy-based foods are also very allergenic and contain phytosterols, which can have other undesirable effects. Soy-based foods are therefore not recommended for infants, especially if they are at increased risk of allergies. 20–30% of infants who are allergic to cow's milk also have soy-milk intolerance.

Most children “grow” out of a food allergy by the age of five. However, since these children are obviously predisposed to allergic diseases, new sensitizations can often arise, for example to pollen allergens, which can then also manifest themselves in other forms of disease ( bronchial asthma , allergic rhinitis). This phenomenon is also known as allergic march .

Food allergies in adolescence and adults

Food allergies in adolescence and adulthood are often not genuine allergies in the sense of an initial sensitization to certain foods. Rather, it is a question of secondary food allergies as a result of cross-allergies , in which the original sensitization is directed against, for example, an inhalation allergen . Usually it is the oral allergy syndrome (OAS) in birch allergy sufferers who are sensitized to the main allergen in birch pollen . Because of the cross-reactivity of the antibodies with a similar protein in apples , people who are allergic to birch pollen can experience allergic symptoms when consuming apples - typically on the oral mucosa . The varieties Braeburn , Gala , Golden Delicious , Granny Smith and Jonagold are particularly often incompatible with other varieties .

Nevertheless, there is “real” sensitization to food even in adolescence and adulthood.

Peanut allergy ( Latin Arachis hypogaea ) is particularly serious . Here, peanut allergens can lead to severe allergic reactions and anaphylactic shock . Therefore, a declaration must be made on food if it contains peanuts. It is often not immediately apparent whether a food contains peanuts or peanut butter ( ice creams , dessert creams , muesli mixes, chocolate bars, etc.).

causes

A distinction must be made between food allergy and intoxication and abnormal reactions that are not immunological in nature, so-called intolerance reactions such as pseudoallergies or enzymopathies . The real food allergy (also food hypersensitivity) is based on an antigen-antibody reaction . It is an overreaction of the immune system against natural and harmless food ingredients. It is triggered by proteins or glycoproteins with a molecular weight of 19 to 90 kDa . In the type I reaction (also immediate type reaction) IgE occur. It is a "real" food allergy. Antibody-dependent cytotoxic hypersensitivity are allergenic reactions of type II. In type III (also immune complex reaction ) the immunoglobulin classes G and M are involved. The reaction type IV describes the contact allergy , which is based on the formation of immunoreactive lymphocytes .

Cross reactions

The hazelnut allergy often occurs in combination with an allergy to tree pollen ( hay fever ). The reason for this may be the plant-based panallergen profilin , which can be found in both hazel pollen and hazelnut extracts .

distribution

In adults, food allergies occur in around 1 to 5% of cases, in children a little more often in around 5 to 10%. Food intolerances , on the other hand, occur significantly more often with an average of around 30%. Allergies to nuts are very common. This is related to the resistance to human digestion and the thermostability of some storage proteins .

trigger

In principle, every food - or its ingredients - can have an allergenic effect, but the allergic potentials are different.

The EU Directive 2007/68 / EC of November 27, 2007 stipulates that the following 14 ingredients (and products obtained from them) must be indicated as possible triggers of food allergies and intolerances on packaged foods, as they most often lead to reactions of the so mentioned immediate type:

1. Eggs
2. peanuts
3. fishes
4. Crustaceans
5. Lupins
6. Milk (including lactose )
7. Nuts , i.e. almonds, hazelnuts, walnuts, cashews, pecans, Brazil nuts, pistachios, macadamia nuts, and Queensland nuts
8. Gluten-containing cereals (eg. As wheat, rye, barley, oats, spelled)
9. Sulfur dioxide and sulphites in concentrations of more than 10 mg / kg or 10 mg / l, expressed as SO ₂ .
10. celery
11. mustard
12. Sesame seeds
13. Soybeans
14. Molluscs (e.g. mussels, snails, squids)

Labelling

Since the Food Information Ordinance came into force, the allergenic foods listed above must be mentioned in the list of ingredients as soon as they are included as an ingredient. The allergenic ingredients that are subject to labeling must be highlighted in prepackaged goods in the list of ingredients by means of a font, for example by the font , the font style or the background color. If no list of ingredients is provided, the information must be given with the word "contains". There is no regulation for unwanted cross-contamination . The trace marking is carried out voluntarily by the food business operator in the sense of product liability .

In the catering industry , the information about the allergenic substances must be based on written documentation. In addition, a trained employee must always be able to provide verbal information. Furthermore, the allergens can be marked on the menu using codes, colors or pictograms.

Food control

The official food control checks the marking on the labels and, if there is justified suspicion, also carries out laboratory analyzes. Allergenic proteins can be detected directly using ELISA . Alternatively, the PCR can be used to indirectly detect the DNA from which proteins are synthesized ( central dogma of molecular biology ). The interpretation of the results by experts is difficult because there are no binding threshold values.

Chylomicrons as antigen vehicles

In a study on mice it could be shown for the first time that the resorption of undigested food proteins occurs mainly via the chylomicron transport, especially if the food contains a lot of triglycerides , e.g. B. peanuts , eggs and milk . In addition, protein antigens have corresponding emulsifier properties, which means that they have a high affinity for chylomicrons.

diagnosis

The simplest and most effective method is to keep a nutrition and complaint diary, with the help of which the temporal relationship between ingestion of the potentially intolerable food and the symptoms can be discovered. It is best to start from a basic diet with some - presumably tolerable - foods and add another food to the diet every few days. With this method, other, non-immunological food reactions (e.g. food intolerances) cannot be differentiated, but can be recorded.

If a certain food is suspected to be intolerant or allergenic, an exclusion diet with food abstinence for several weeks and a subsequent provocation diet should follow . Exclusion diet and provocation diet are carried out one after the other for the individual foods, e.g. B. Milk, shellfish, etc. Another recommended method is a rotation diet , in which potentially allergenic foods are eaten in a certain cycle.

Further medical diagnostic procedures:

• Skin tests with various food extracts (e.g. prick test )
• Determination of the total IgE in the serum
• Determination of allergen-specific IgE antibodies in the serum (e.g. RAST test )
• Determination of allergen-specific IgE antibodies in different sections of the digestive tract (e.g. gastrointestinal lavage )
• Methylhistamine determination in the 24-hour urine during a normal diet and then, for comparison, during a multi-day, low-allergenic potato-rice diet (see below).

There are providers of unsuitable test procedures for the detection of assumed food allergies. For example, an IgG test is not generally suitable for diagnosing a food allergy. The IGeL monitor of the MDS (Medical Service of the Central Association of Health Insurance Funds) evaluates the immunoglobulin G determination for the diagnosis of a food allergy as "negative". After evaluating the scientific literature, there was no evidence of any benefit, since a high concentration of IgG is not associated with allergy symptoms. In addition, another type of immunoglobulins is responsible for allergies. At the same time, there are indications of considerable damage if the test leads to an unnecessary restriction in diet or, in extreme cases, even to malnutrition. Allergologist associations and the German Medical Journal are also critical in this regard (see also ALCAT test ).

prevention

To prevent food allergies, it makes sense not to eat the same foods too often, and especially not every day. In general, frequent contact is a common cause of allergies. For example, the same mixture of vegetables should not be eaten in salads every day, because many potentially allergenic substances are absorbed here.

Breastfeeding is a good preventative measure. Children who are exclusively breastfed suffer from food allergies far less often than children who were not breastfed.

Individual evidence

1. ↑ Food allergy: MedlinePlus Medical Encyclopedia. Retrieved May 28, 2018 . 
2. ↑ Susanne C. Diesner, Isabella Pali-Schöll, Erika Jensen-Jarolim, Eva Untersmayr: Mechanisms and risk factors for type 1 food allergies: the role of gastric digestion. doi: 10.1007 / s10354-012-0154-4
3. ↑ A. Auer, D. Grach, E. Fattinger: Breast milk as an allergen carrier. Sense and nonsense of an allergen-avoiding diet while breastfeeding. In: Nutrition / Nutrition. Vol. 34, 10 (2010), PDF file ( Memento of the original from December 22, 2015 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
4. ↑ P. Altmeyer, M. Bacharach-Buhles: Dermatology, Allergology, Environmental Medicine. Springer Verlag, Berlin 2002, ISBN 3-540-41361-8 , p. 857, some of which can be viewed at Google Books
5. ^ Association for the Environment and Nature Conservation Germany Lemgo, Info Apple Allergy
6. ↑ Hans Steinhart , Angelika Peschke, Katy Zunker: Food allergy - an individual danger. In: Biology in Our Time. 31 (6), 2001, ISSN  0045-205X , pp. 398-407, doi : 10.1002 / 1521-415X (200111) 31: 6 <398 :: AID-BIUZ398> 3.0.CO; 2-M
7. ↑ Reinhold Hirschwehr, Rudolf Valenta, Christof Ebner, Fatima Ferreira, Wolfgang R. Sperr: Identification of common allergenic structures in hazel pollen and hazelnuts: A possible explanation for sensitivity to hazelnuts in patients allergic to tree pollen . In: Journal of Allergy and Clinical Immunology . tape 90 , no. 6 , December 1992, pp. 927-936 , doi : 10.1016 / 0091-6749 (92) 90465-E .
8. ↑ Classification of reactions to food ( memento of the original from March 16, 2013 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. . NMI portal website. Retrieved June 19, 2012. 
9. ↑ LADR informs No. 219: Nut allergy a common food allergy - 12/2014
10. ↑ DIRECTIVE 2007/68 / EG (PDF) of the EU Commission of November 27, 2007.
11. ↑ Bavarian State Office for Health and Food Safety : Labeling of allergens in food
12. ↑ LADR informs: Allergens in food
13. ↑ Alexandros Rambacher, Robert Stein: Allergen labeling in practice. (PDF) In: www.orf.at. Lower Austria Chamber of Commerce - Specialist Groups Gastronomy and Hotel Industry, August 2014, accessed on October 16, 2016 . 
14. ↑ GDCh : "Allergens in Food - Legal Basics and Detection Strategies"
15. ^ Y. Wang, S. Ghoshal, M. Ward, W. de Villiers, J. Woodward, E. Eckhardt: Chylomicrons promote intestinal absorption and systemic dissemination of dietary antigen (ovalbumin) in mice . In: PLoS ONE . tape 4 , no. 12 , 2009, p. e8442 , doi : 10.1371 / journal.pone.0008442 , PMID 20041190 , PMC 2793525 (free full text).
16. ↑ IGeL-Monitor, Immunogloblin G determination for the diagnosis of a food allergy , accessed on November 15, 2018. More on the justification for the assessment in the evidence thesis
17. ↑ Allergologist associations warn against dubious tests for IgG
18. ↑ Jörg Kleine-Tebbe, among others: Food allergy and intolerance. In: Dtsch Arztebl. [Issue 27] 2005; 102, pp. A 1965-A1969.
19. ↑ AOK.de ( Memento from January 12, 2012 in the Internet Archive )
20. ↑ dha-allergien.de: Nutrition for food intolerances , accessed on May 5, 2013.

literature

• Arnold Hilgers, Inge Hoffmann: Food Intolerance . Mosaik, Munich 1997, ISBN 3-576-10742-8 .
• Karin Buchart: Food allergy. A guide for those affected. 2., revised. Edition. Studien-Verlag, Innsbruck 2005, ISBN 3-7065-1905-4 .
• Karin Buchart: Living well with food allergies. Guide with a diet plan and recipes for all concerned. 3rd, revised. Edition. Löwenzahnverlag, Innsbruck 2008, ISBN 978-3-7066-2417-6 .
• Simone Graebner: Allergy subjects / Foodfan - food, allergies, intolerances, malabsorption. 1st edition. Behr's Verlag, Hamburg 2012, ISBN 978-3-89947-857-0 .
• Zopf, Yurdagül et al .: Differential diagnosis of food intolerance . In: Dtsch Arztebl Int . No. 106 (21) , 2009, pp. 359-369 ( Article ).
• CE Olivier: Food Allergy. In: J Allergy Ther. 2013; S3, p. 004 URL

Web links

Wiktionary: Food allergy  - explanations of meanings, word origins, synonyms, translations

• German Nutrition Advice and Information Network (DEBInet): Food allergies
• Food allergies - kindergesundheit-info.de: independent information service from the Federal Center for Health Education (BZgA)
• Database with "over 4000" potential allergens.

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !