There are a multitude of ways to shock an audience, but it is not every day that a news item causes fear, disdain, and skepticism all with one headline. Yet somehow the International Agency for Research on Cancer (IARC) managed to do just this on Oct. 26 by announcing that everyday food items such as bacon and red meat are now classified respectively as ‘carcinogenic to humans’ (Group 1) and ‘probably carcinogenic to humans’ (Group 2A).
This classification and the way in which it was widely publicized is problematic on several accounts, foremost of which is the method of classification itself. Here carcinogens are grouped according to strength of evidence, not risk factor. This led to many headlines trumpeting that eating bacon is just as dangerous as smoking in terms of cancer risk, which is completely untrue. The Group 1 classification merely means that after reviewing certain pieces of literature, the agency believes it has enough evidence to associate processed meats with cancer incidence; the actual risk associated with eating foods such as bacon is vastly lower than the risk associated with smoking. And this brings up another point of contention—while IARC tells us that eating bacon and red meat can increase risk of colon cancer by 18 percent, it does not specify what exactly the resulting risk factor is. And given that the lifetime risk of colon cancer for men and women is a fairly low 4.5 percent, adding bacon to equation does not cause a huge rise in risk. That 4.5 percent is increased by 18 percent (note that these percentages are not additive), making the total lifetime risk more like 5.3 percent—and remember that this is based on the average human consuming roughly two slices of bacon every single day. This statistic is certainly something to be aware of, but is much less worrisome than it needs to be. It is also a far cry from the risk caused by smoking two cigarettes a day.
And of course by only reviewing literature, it is nearly impossible to directly correlate health with anything. Perhaps those who eat less bacon, and are therefore at lower risk for cancer, tend to lead healthier lifestyles in general. Or maybe excessive bacon consumption is just a marker for other unhealthy eating habits. There have indeed been studies on the long term effects of processed and red meat on health, however IARC provides limited data in their announcement and can pick and choose the literature that gets reviewed.
So the takeaway: are red and processed meats going to give us cancer? Probably not. There is a health risk associated with eating them, but if consumed in moderation they are not significantly riskier than most other food items that we regularly eat. There are also nutritional benefits that should be considered when evaluating red meat in our diet, as red meat is often a main source of iron and protein. Should we be worried about this? Probably not. This information has been publicized for some time now and if one is consuming enough processed meat to be cause a significant cancer risk, there are many other health problems that will most likely occur first (heart disease, high cholesterol, etc.). So while eating hamburgers daily should probably be avoided for many reasons, we should not be worried about the occasional hot dog or indulgence of bacon.