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 - Update:
Soybean (Glycine max) ........................................... |
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Authors in alphabetical order [contact
information]
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Abstract
Soybean is the most important nutrient of the legume family. Allergy
to soybeans is common in food allergic children younger than 3 years of
age. Adverse reactions caused by soybean formulas are seen in 14-35% of
cow's milk allergic infants. In food allergic subjects with atopic dermatitis
egg, milk, peanut, and soybean account for almost 90% of allergic reactions.
The prevalence of soybean allergy in the general population is probably
below 0.5%. Symptoms range from skin, gastrointestinal, and respiratory
reactions to severe systemic reactions including anaphylaxis. There are
several reports of inadvertant ingestions of soy protein which caused life-threatening
allergic reactions. Fatal reactions to soybean have also occurred in peanut
allergic individuals, whose sensitivity to soybean was not recognized previously.
Soybean products are used in the manufacture of foods with almost
no limits, e.g. as a texturizer, emulsifier, or protein filler. Therefore
it is a particularly harzardous hidden allergen in pastries, bakery products,
infant foods, sausages, processed meats, and hamburgers. Fermented soybean
products such as miso, tempeh, shoyu, and natto are potentially less allergenic
than raw soybeans. However, even acid and mold-hydrolyzed soy sauce retain
significant allergenic potencies. While soybean lecithins can induce allergic
reactions, highly refined soybean oils are generally safe. Soybeans and
its products should always be declared according to a list of the Codex
Alimentarius Commission on mandatory labelling of prepackaged foods.
About 16 soybean allergens have been identified. Major ingestive
allergens are the following water soluble proteins: Gly m Bd 30K (thiol-protease
P34), the storage proteins glycinin and beta-conglycinin, and profilin
(Gly m 3). Several sequential IgE-binding epitopes have been identified
on Gly m Bd 30K, while studies with recombinant profilin fragments indicate
the predominant role of conformational epitopes. On the other hand soybean
hull proteins Gly m 1 and Gly m 2, and the Kunitz-trypsin inhibitor are
involved in respiratory hypersensitivity reactions. Soybean dust has caused
several epidemic incidents of asthma in soybean mill workers, harbour workers
and animal feed workers as well as in bakers. In asthma, cross-reactivities
between soy flour and wheat, rye, and barley flours could be observed.
Although there is extensive in vitro cross- reactivity among various
legumes, e.g. soybean, peanuts, peas, and beans, clinical reactivity is
usually limited to a single legume source.
The present review summarizes data on prevalence, symptoms, diagnostic
features, allergenic potencies of processed foods and transgenic soybeans,
allergen sources, and infant formulas as well as molecular biological and
allergenic properties of the major soybean 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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