Dietary Management
Ernährung und Allergie
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Dietary Management |
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Ernährung und Allergie |
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| Allergen Data Collection:
Peanut (Arachis hypogaea) ................................................ |
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Authors in alphabetical order [contact
information]
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Abstract
Among food allergy, peanut allergy is common and severe. Epidemiologic studies of the general population estimate a prevalence rate of 0.5%, and peanut allergy accounts for 10-47% of food- induced anaphylactic reactions. Symptoms may vary in severity from mild urticaria or localized oral symptoms, to severe systemic reactions that can be fatal. Reactions typically occur within a few minutes following ingestion. Peanut hypersensitivity usually begins in early childhood and usually persists throughout life, with only a small percentage of young children achieving tolerance.
Diagnosis rests upon a clear history of severe reaction with laboratory evidence of peanut-specific IgE antibody. Reactions could be confirmed by oral challenge procedures, when anaphylactic reactions are not expected. Diagnostic skin prick tests and determination of specific IgE are sensitive and have an excellent negative predictive value. Since very small amounts of peanut protein can elicit an allergic response, and the food is ubiquitous in most food supplies, accidental ingestion with reaction is common. Hidden peanut proteins have been reported as causes of adverse reactions to confectionary products, pastry, and Asian food. While crude peanut oil can induce allergic reactions, the allergenicity of refined peanut oils is controversial. Although peanut shares cross-reacting proteins with other legumes (e.g. - soybean, pea), clinical cross reactivity is not common, except for possibly lupine. Allergy to peanut most commonly occurs in atopic individuals who may have other food allergies (e.g. - egg, tree nut), but there are no known clinically relevant cross reacting proteins with tree nuts (e.g. - walnut). Peanuts and its products should always be declared according to a list of the Codex Alimentarius Commission on mandatory labelling of prepackaged foods. Although there are some promising advances in immunotherapy of peanut allergy, the only currently available treatment consists of strict avoidance with immediate availability of epinephrine for self-injection in the event of an accidental ingestion.
Three major peanut allergens are recognized by more than 50% of peanut
allergic individuals: Ara h 1 (vicilin), Ara h 2 (conglutin- homologue
protein), and Ara h 3 / Ara h 4 (glycinin). These allergens are seed storage
proteins and their primary structure and major IgE-binding epitopes have
been characterized. More recently three additional minor allergens Ara
h 6 and Ara h 7 (both conglutin- homologue proteins) as well as the plant
pan- allergen profilin (Ara h 5) were described.
The present review summarizes data on prevalence, symptoms, diagnostic
features, immunotherapy, allergen stability, and allergen sources as well
as molecular biological and allergenic properties of the major peanut allergens
in tabular form.
Disclaimer
The reference lists of the Allergen Data Collections
are based mainly on searches of Medline and FSTA (Food Science & Technology
Abstracts) databases up to the related dates of publication. The scientific
rigor of the studies listed is variable and not subject of critique or
evaluation by the authors or the editor of the Allergen Data Collections.
The reader should be aware of considerable problems in comparing data from
different studies (eg. patient cohorts, diagnostic performances, possible
flaws in allergen preparations and methodologies for allergen characterization)
and is encouraged to review the original publications.
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Food Allergens is for educational, communication and information purposes
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