Eating processed meats causes cancer, and red meat probably increases cancer risks. That’s the judgment of a panel of global experts panel of global experts assembled by the World Health Organization to consider the accumulated scientific evidence on the question. Eating an extra 50 grams daily of processed meat increases the risk of colorectal cancer by 18 percent, the WHO said today. While the overall risk is small, it "increases with the amount of meat consumed,” the organization said. But what does it mean to say processed meat causes cancer?
They fall into one of five classifications, according to the strength of the evidence: agents or activities that definitely, probably, or possibly cause cancer in humans; those that probably don’t cause cancer; and those for which the evidence is inconclusive.
It’s important to note that the agents at the top aren’t necessarily the most dangerous. They’re the ones with the clearest evidence of hazard. WHO seeks to identify carcinogens “even when risks are very low at the current exposure levels, because new uses or unforeseen exposures could engender risks that are significantly higher,” the agency says. In other words, even though WHO has determined that red meat is a carcinogen, the report doesn’t quantify how much meat it would take to cross into the danger zone.
The list of possible carcinogens WHO has identified thus far is filled with strange-sounding chemicals. But it includes familiar foods and products that millions of people encounter every day.
No one will be surprised to find tobacco on the list. Alcohol, too, has been deemed a carcinogen. When coffee was evaluated in 1991, scientists found limited evidence that it may cause bladder cancer.
The World Health Organization’s cancer label carries weight. In March, the agency identified the most widely used herbicide in the world, glyphosate, as a probable carcinogen. Monsanto, the maker of the glyphosate-based weed killer Roundup, pushed back against the designation, but France banned retail sales of the herbicides in June. After a coconut-oil derivative called cocomide DEA was judged a possible carcinogen in 2013, environmental groups pressured manufacturers including Colgate-Palmolive to remove it from shampoo and personal-care products.
The meat industry has been bracing for the WHO report for months, and it’s attempted to counter research linking meat to cancer for years.
Correction: The original version of this story misstated the amount of processed meat that increases the risk of colorectal cancer. It is an extra 50 grams daily, not an extra 50 grams.
Correction: In referring to a drink called hot mate, a previous version version of this graphic mistakenly highlighted a different drink, called mate.