Earlier this week, there was a ton of news coverage of a new World Health Organization (WHO) report concluding that processed meat is a carcinogen and that eating a couple of pieces of bacon a day will increase rates of certain types of cancer by 18%. The Guardian ran a story with the headline, “Processed meats rank alongside smoking as cancer causes – WHO,” and blogs like Medical Daily posted something called, “Red Meat Is Just As Likely To Give You Cancer As A Cigarette, The World Health Organization Says.”
Let’s consider these headlines a bit more carefully.
It’s pretty clear that “ranking alongside smoking” is a bit of a simplification. The WHO has categories for things with respect to their potential to cause cancer. The new report does, indeed, add processed meats to the Group 1 category, which includes things that are considered “carcinogenic to humans.” The WHO is very clear that things in this group are known to cause cancer, but makes NO claims about their cancer causing potency. It makes no claims about how much of a risk the substance is. For a little perspective, “ethanol in alcoholic beverages” is also on Group 1, so is “leather dust” and “wood dust.” Just knowing that something can cause cancer doesn’t tell us anything about the likelihood that it will actually cause cancer.
But the inclusion of processed meats in the list of known carcinogens should give us some pause, and make us think a bit about the risk. This is where the main question of what’s important and why gets some relevance. The report tells us that “each 50 gram portion of processed meat eaten daily increases the risk of colorectal cancer by 18%.” This sounds bad, because an 18% increase sounds like a lot, but 18% of what is the important question. The WHO group responsible for the report, the International Agency for Research on Cancer (IARC), estimates that 34,000 cancer deaths per year, worldwide, are attributable to eating processed meats. Again, 34,000 deaths sounds like a lot…unless you realize that more than 55 million people die each year. So the cancer deaths caused by eating processed meats end up being less than 0.062% of all deaths worldwide. Yet, this is getting all kinds of attention, and will likely influence the eating decisions of many people around the world.