Soy lecithin

Cross-reactivity

Case notes

On an ingredient panel, this one often shows up simply as "lecithin" — or as the additive code E322, or the British spelling "soya lecithin." All three point to the same soy-derived ingredient, and only one of them contains the word soy. That is the core label-reading problem: a scan tuned to spot "soy" can slide right past a listing that never spells it out.

Soy lecithin sits in the Legumins (11S Globulins) family, alongside Gly m 6, and also carries vicilin-family proteins such as Gly m 5 (β-conglycinin). Those same storage protein families explain why soy appears in legume cross-reactivity notes: vicilin and legumin proteins in peanut (Ara h 1 and Ara h 3) share structural homology with their soy counterparts, and roughly 5 to 10 percent of peanut-allergic people react to soy. So a label that reads only "lecithin" can matter to more than one household, depending on what an allergist has already established.

The nuance worth holding onto is this: most soy-allergic people tolerate soy lecithin because it carries very little protein. That is genuinely useful context, but it is an allergist conversation, not a conclusion to draw in a grocery aisle. The practical habit is to recognize "lecithin" and "E322" as soy-derived names when you see them, log them the way you would any other soy listing, and let the specifics of your child's plan — not the label alone — decide what happens next. Related names like soy protein isolate and hydrolyzed vegetable protein deserve the same second look.