Exposure to aflatoxin, a group of toxins produced by mould that grows on cereals, spices, and nuts, could be behind up to 28% of global cases of the most common form of liver cancer, according to a risk assessment published in Environmental Health Perspectives. More than five billion people worldwide are exposed to uncontrolled levels of the toxin.
Aflatoxin contamination in food is a serious global health problem, particularly in developing countries,” write Yan Liu and Felicia Wu from the University of Pittsburgh in Pennsylvania, USA. The toxin could account for 28% of all cases of hepatocellular carcinoma (HCC), with sub-Saharan Africa, South-East Asia, and China shouldering the heaviest burden.
Aflatoxin is produced by a fungus that can grow on food crops in tropical and subtropical climates. Maize and groundnuts, staple foods of many African and Asian diets, are most prone to having the mould. As many poor people living in these regions cannot afford a varied diet, potentially contaminated foods make up a significant proportion of their diets. People in these regions are also more likely to be infected with the hepatitis B virus, which raises the odds of developing aflatoxin-related liver cancer 30-fold compared with uninfected people.
Although it has been known for some time that aflatoxin is carcinogenic, this is the first study to estimate the proportion of liver cancer cases worldwide attributed to the exposure.
The amount of aflatoxin that contaminates food can be reduced by drying and storing grains properly. Sorting and washing the grains before cooking can also reduce levels of the harmful substance. The global prevention strategies should include education campaigns to improve the public’s awareness of the risks.
While it is impossible to completely eliminate aflatoxin in food worldwide, it is possible to significantly reduce levels and dramatically reduce liver cancer incidence worldwide, the authors conclude. The challenge remains to deliver these interventions to places of the world where they are most needed.
Reference and link: Liu Y, Wu F. Global burden of aflatoxin-induced hepatocellular carcinoma: a risk assessment. Environ Health Perspect 2010.