On any given day, a child under five in sub-Saharan Africa or South-East Asia sits down to a meal that carries risks an adult in the same household does not. That asymmetry is now quantified. New estimates published by the World Health Organization show that children below the age of five, who represent just 9% of the global population, account for nearly one third of all foodborne illness cases worldwide — a rate of exposure almost three times higher than that faced by older children and adults. The numbers behind that disproportion are striking.

Unsafe food causes roughly 866 million illnesses and 1.5 million deaths every year, the WHO calculated for the reference year 2021. The vast majority of those illnesses — approximately 860 million — are driven by biological hazards such as bacteria, viruses and parasites. Yet it is chemical contamination that kills most efficiently.

Inorganic arsenic and lead together account for nearly three quarters of all food-related deaths, largely because prolonged exposure dramatically raises the risk of heart disease and certain cancers. For young children, the consequences extend further still: methylmercury and lead absorbed through contaminated food can permanently impair the developing brain.