Andy Bellatti for Civil Eats
When the World Health Organization (WHO) International Agency for Research on Cancer (IARC) announced in October that processed meat causes cancer in humans, and all red meat “probably” does, the internet lit up with expressions of shock and horror.
“Everything you love wants to kill you,” read one blog. “They’re coming in their black helicopters for your bacon,” wrote New York Times science editor Michael Roston in a tweet.
But joking aside, this really isn’t a controversy.
Yes, WHO’s finding puts processed meat in the same category as smoking and asbestos, but any headlines that equate a bite of sausage with smoking a cigarette have it wrong. As the agency explains, “the IARC classifications describe the strength of the scientific evidence about an agent being a cause of cancer, rather than assessing the level of risk.” In other words, processed meats and cigarettes are not equally risky; rather, the current evidence that they are both carcinogenic is equally strong.
These conclusions were reached after an international panel of experts reviewed over 800 studies examining the link between red meat eating and cancer. Specifically, consuming 50 grams (slightly less than two ounces) of processed meat a day was found to increase colorectal cancer risk by 17 percent, while eating 100 grams (three and a half ounces) of red meat a day increased that same risk by 18 percent.
A 50 year old man has a 0.68 percent risk of developing colorectal cancer in the next 10 years, so daily consumption of processed meat increases it to 0.8 percent. It’s still less than one percent, but the only foods known to increase that risk are processed and red meat. (Red meat is defined as “all types of mammalian muscle meat, such as beef, veal, pork, lamb, mutton, horse, and goat.”)
To be clear, risk exists on a continuum. Theoretically, we risk our lives every time we get behind the wheel of a car. However, the risk of getting into an accident varies greatly if one is driving 100 miles an hour versus 20, if one is texting or focused on the road, if one is wearing their seatbelt or not. Driving without a seatbelt at high speeds while distracted does not guarantee a fatal accident; it simply raises the risk. Dietary cancer risk is much harder to tease out because of confounding factors: genetics, stress level, the overconsumption (or under consumption) of other foods, smoking habits, and physical activity, to name a few. Nevertheless, there is solid data to show that diets rich in processed and red meats carry more risk when it comes to some cancers.
Although these findings made headlines this week, they’re not necessarily groundbreaking or new. The American Institute for Cancer Research (AICR) has longrecommended [PDF] limiting red meat intake to no more than 18 ounces a week and avoiding processed meats entirely (AICR explicitly states that “there is no safe threshold” for the latter). The Dietary Guidelines Advisory Committee found the evidence that diets high in red meat and processed meats increase the risk of colorectal cancer “convincing”—a word the committee used sparingly throughout its report. And many studies have reported a significant association between high intakes of red and processed meats, with increases in cancer incidence and death, especially at high doses.