Groundnut

Cross-reactivity

Case notes

"Groundnut" is peanut. It is the same food, the same proteins, and the same risk — just a different word, and one that scans past the eye quickly when you are checking a package in a school hallway or a party kitchen. The word carries no visual echo of "peanut," so a label search that relies on spotting those six letters will come up empty. The same is true of the other names in this family: goober, monkey nut, and the botanical name Arachis hypogaea all point back to peanut.

What makes those synonyms worth memorizing is what they carry. Groundnut belongs to the Legumins (11S Globulins) family, with Legumin (Ara h 3) among its named proteins, and also to the Vicilins (7S Globulins) family, home to Vicilin (Ara h 1) — a seed storage protein that stays stable through processing and can persist in refined products. Reactions in these families are described as usually moderate to severe, and the vicilin family carries a note that it can cause anaphylaxis.

There is a second layer for households already reading labels for soy. Ara h 1 shares structural homology with Gly m 5 (soy vicilin), and Ara h 3 with Gly m 6 (soy legumin) — moderate cross-reactivity through shared storage proteins, with roughly 5 to 10 percent of peanut-allergic individuals reacting to soy. Logging which specific label word appeared, rather than just "peanut," makes patterns easier to see later.