Library: Fermented soybeans: natto
A 38 year old man developed an anaphylactic reaction with flushing, generalized urticaria, conjunctival redness, and breathing problems three hours after eating cold Chinese noodles. He had avoided natto for the previous year as a result of experiencing anaphylactic reactions half a day after eating natto.
Skin prick tests were strongly positive for natto and the soup of cold Chinese noodles. The tests were also positive for poly gamma-glutamic acid (PGA), which is a major constituent of natto mucilage, an ingredient of the noodle soup.
The man was diagnosed with late-onset anaphylaxis to PGA contained in natto and the cold Chinese noodle soup. The delayed reaction was thought to be due to a delayed absorption of PGA which has to biodegrade to peptides sufficiently small enough to be absorbed in the bowel.
Inomata et al note that PGA has recently been applied to a wide range of fields such as foods, cosmetics, and medicine and that anyone with a sensitivity to to PGA of natto should avoid not only natto but also other materials containing PGA.
Late-onset anaphylaxis due to poly (gamma-glutamic acid) in the soup of commercial cold Chinese noodles in a patient with allergy to fermented soybeans (natto).
Inomata N, Chin K, Nagashima M, Ikezawa Z.
Allergol Int 2011 Mar 25.