Maybe, the doc just gave him some complicated theory.
Me and him, personally, think the doctor had no idea and was just quoting something he probably read.
For what its worth, my friends son, is pretty healthy, smart, and a good athlete so this hasn't had much affect on his day to day life (outside of having to carry his "emergencies").
He is also smart enough to not eat any thing unless his parents say so.
Was he fed a soy-bean based formula as an infant?
Allergy. 1999 Mar;54(3):261-5. Related Articles, Links
A study on severe food reactions in Sweden--is soy protein an underestimated cause of food anaphylaxis?
Foucard T, Malmheden Yman I.
Department of Paediatrics, University Hospital, Uppsala, Sweden.
BACKGROUND AND METHODS: Because of a fatal case of soy anaphylaxis occurring in Sweden in 1992, a study was started the following year in which all physicians were asked to report fatal and life-threatening reactions caused by food. The results of the first 3 years of the study are reported here, including results from another ongoing study on deaths from asthma during the same period. RESULTS: In 1993-6, 61 cases of severe reactions to food were reported, five of them fatal. Peanut, soy, and tree nuts seemed to have caused 45 of the 61 reactions, and four of them were fatal. If two cases occurring less than a year before our study started are included, we are aware of two deaths caused by peanuts and four deaths caused by soy. All four youngsters who died from soy anaphylaxis with asthma were severely allergic to peanuts but had no previously known allergy to soy. In most cases, there was a rather symptom-free period for 30-90 min between early mild symptoms and severe and rapidly deteriorating asthma. CONCLUSIONS: Soy has probably been underestimated as a cause of food anaphylaxis. Those at risk seem to be young people with asthma and peanut allergy so severe that they notice symptoms after indirect contact.