Soy (soja) is a common food allergen, especially in infants. Allergy to soy affects about 0.5% of the population.
What are the reactions associated with soy?
The term allergy to soy corresponds to immediate reactions to soy which involve IgE antibodies, and that are characterized by skin, respiratory, digestive and sometimes cardiovascular symptoms (see the section on Food allergy). Other reactions involving the immune system and particularly the gastrointestinal tract are related to soy, as they are with milk (see the section on Food related enteropathies).
How does one avoid soy?
As for most other food allergies, treatment always begins with avoidance. In addition to informing those around you and taking precautions to avoid contamination, you must attentively read all food labels, since soy protein can be found in many different foods. Other names can be used to designate soy: soja, miso, tofu, edamame, vegetable protein, etc. (see the site of the Canadian Food Inspection Agency for a more exhaustive list). In Canada, a law mandates that the word "soya" be clearly indicated on the list of ingredients. It is possible that certain people only react to larger quantities of soya, and not to smaller traces - for this,you must speak with your allergist.
What is the evolution of a soy allergy?
In the majority of cases an allergy to soy disappears, often before school age.
Nha Uyen Nguyen-Luu, MD FRCPC
(translation: Andrew Moore, MD FRCPC)