The Origins of Peanut Allergy

A researcher recounts hearing that before 1980 there were effectively zero known fatalities from peanut allergy and outlines why the modern U.S. epidemic may be tied to uniquely American peanut consumption habits - principally peanut butter. A colleague’s lab tested the idea that processing emulsifiers in peanut butter cause intestinal damage and allergy, but those cell-culture results were unconvincing. Instead, a 1980 agricultural disaster - a severe drought that both gutted the peanut crop and encouraged Aspergillus flavus contamination - stood out. That fungus produces aflatoxin, an extremely toxic, carcinogenic compound, and around 15% of the surviving crop that year was rendered moldy; economic pressure could plausibly have driven some spoiled peanuts into processed products.

The central argument is that aflatoxin acted like a powerful immunological adjuvant during that crisis, turning otherwise benign peanut proteins into a signal that trained immune systems to overreact, which fits the timing of the first recorded fatal allergic reactions. This model parallels how adjuvants amplify vaccine responses and dovetails with evidence that early, repeated dietary exposure protects against allergy; children who lacked prior peanut exposure and then encountered tainted peanut butter would be especially vulnerable. The piece cites epidemiology (roughly 1% of U.S. children affected) and contrasts U.S. peanut-butter culture with low rates elsewhere to explain why the surge was concentrated in America.