The World Health Organization’s International Agency for Research on Cancer (IARC) has, as expected, delivered a damning report linking meat consumption and cancer, in particular a strong link between processed meats and colorectal cancers.
IARC is the leading body that determines the cancer-causing risks of exposure to everyday substances. It classifies substances from Group 1 (carcinogenic to humans) to Group 4 (probably not carcinogenic to humans).
High consumption of processed meat—which has been “transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation”—has been given a Group 1 classification, which puts it in the same class of cancer risk as tobacco smoke. Red meat has been categorized as a Group 2A carcinogen, “probably carcinogenic to humans,” the same classification given to the controversial pesticide glyphosate.
One meta-analysis of colorectal cancer found an increased risk of 17% per 100 g of red meat eaten daily and an 18% risk per 50 g of processed meat. By one estimate, US men eat an average of 110 g of red meat a day. Women eat an average of 70 g.
There are more than 100 agents on IARC’s Group 1 classification, including alcohol, X-rays, air pollution, and sunlight. The meat-cancer link, as with all cancer-causing agents, is dose-dependent.
“This decision doesn’t mean you need to stop eating any red and processed meat. But if you eat lots of it you may want to think about cutting down,” Tim Key, Cancer Research UK’s epidemiologist at the University of Oxford, said in a statement.
The North American Meat Institute (NAMI), the trade group representing 95% of red meat processors in the US, had been hoping for a 2B classification, or “possibly carcinogenic to humans,” a representative said earlier this year.
In a press release, NAMI criticized the finding, saying IARC did not consider the health benefits of eating meat. “Risks and benefits must be considered together before telling people what to eat, drink, drive, breathe, or where to work,” NAMI’s Betsy Booren said. The IARC did note that meat is high in protein, iron, zinc, and other micronutrients, but said that processing meat “can result in the formation of carcinogenic chemicals.”