How might meats be linked to colorectal cancer?

Processed meats like hot dogs and sausages have been salted, cured or smoked to enhance flavor and improve preservation. Scientists have long worried that this processing leads to the formation of potentially carcinogenic chemicals like polycyclic aromatic hydrocarbons in these products.

The concern with red meats — beef, pork and lamb — has more to do with the cooking, not the processing. Grilling, barbecuing and pan-frying meat creates potential carcinogens, including heterocyclic aromatic amines.

The report finds a link between consumption of processed meats and colorectal cancer (and perhaps other cancers), but also acknowledged that the link between red meat and cancer has not been proved.

“Eating red meat has not yet been established as a cause of cancer,” the I.A.R.C. said in a handout accompanying its report.