Q: Following a severe reaction to a product containing soy protein, our 13-year-old was officially diagnosed with a soy allergy.
The allergist said soy lecithin is “usually tolerated” by those with soy allergy. But my daughter has now had two suspicious incidents of hives with the lecithin. Should she avoid it, too?
Dr. Sharma: As your allergist may have explained, soy lecithin is a lipid derivative of soy that contains only trace amounts of soy protein. It is commonly used as an emulsifier in processed foods.
In limited laboratory studies, it has been found that the residual proteins in soy lecithin can bind to IgE (the antibody responsible for allergic reactions).
However, only a few cases of apparent allergic reactions to this additive have been reported, and the actual risk has not been widely studied.
As a result, most allergists do not advise patients with soy allergy to avoid soy lecithin. But given the two incidents of hives after your daughter ate food containing this additive, be sure to discuss this further with her allergist.
If you have the labels from these foods, you may wish to bring those along to an appointment for review.
Dr. Sharma is an allergist, clinical researcher and associate professor of pediatrics. He is Chief of the Division of Allergy and Immunology at Children’s National Medical Center in Washington D.C. and Director of the Food Allergy Program. He co-authors “The Food Allergy Experts” column in Allergic Living‘s e-magazine. Questions submitted will be considered for answer in the e-magazine.
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