The IARC’s Working Group was chaired by Professor Bernard Stewart from UNSW Medicine & Health, who is an internationally recognised expert in environmental carcinogenesis (cancer causation).
Ultimately the IARC classified processed meat as a carcinogen, meaning they found sufficient evidence that eating processed meats causes colorectal cancer.
So, how does this work? There are several explanations, the first and foremost being nitrites found in processed meat products.
“Processed meat, at least historically, has been processed using sodium nitrite,” Prof. Stewart said. “That nitrite can react with molecules in the body to form N-nitroso compounds, which are cancer-causing substances.”
Cooking processed meat, particularly over high heat or an open flame, can also be part of the problem.
“There are also carcinogens that are not inherently present in the meat but are generated during cooking. For example, polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs),” Prof. Stewart said.