The carcinogenic effects of these meats are pretty much all linked to three types of molecules: heterocyclic amines, polycyclic aromatic hydrocarbons, and N-nitroso compounds. The first two form in red and processed meats during high-temperature cooking, while your colon produces the third when it’s exposed to high levels of heme iron (which is what gives red meat its hue).

Processed meats also contain nitrates and nitrites, both of which may contribute to the formation of N-nitroso compounds.

These molecules contribute to cancer risk in multiple organs, including the colon, the stomach, and the pancreas, by directly causing (DNA changes) mutations in cells that can add up over time.