Does Processed Meat Really Cause Cancer? It's Complicated

Bacon and processed meats are beloved by many across the globe, but the WHO has just classified processed meat as a class 1 carcinogen. Research may be telling us to stay clear, but why?

A wake up call or just exaggeration?

The World Health Organization has now ranked processed meat as a Class 1 carcinogen, alongside smoking, arsenic and alcohol. With red meat trailing below in class 2, what data is behind the warning? While vices like smoking are widely known to be damaging, most people wouldn't consider the humble sausage to be a harbinger of cancer.

What does the data say?

There is data linking processed meat to some types of cancer - primarily bowel. This is unfortunately quite well established, but the warning doesn't specify how strong the connection is, and how much is required. Red meat carries a more moderate warning, with weaker links to prostate and pancreatic cancer. Like most things however, the danger is dose dependent. If you engage in the odd beer you're unlikely to experience significant health risks, but for those who get rather too merry too often, risk starts to rise. The same can be said for meat.  

“For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed. In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance.”

Let's put it into perspective

Smoking increases risk of lung cancer by 2500%, but eating 50g of processed meat a day raises colorectal cancer risk by 18%. This is equivalent to roughly one sausage, or two slices of bacon daily. So while there is a link, compared to other carcinogens it's reduced and depends on frequent intake. 

“What we do know is that avoiding red meat in the diet is not a protective strategy against cancer. The top priorities for cancer prevention remain smoking cessation, maintenance of normal body weight and avoidance of high alcohol intakes.”.

What's so bad about processed meat?

Processed meat is treated with nitrates like sodium nitrate. These can be converted to carcinogenic molecules called nitrosamines. Nitrates help preserve foods, but they're also common in vegetables; the difference may be that vegetables come with a bunch of counteracting 'positive' molecules too. The risk of nitrates isn't yet totally understood and remains mostly a theory at this point. Other issues with processed and red meat in particular, is that the iron based heme group that gives the meat its characteristic scarlet hue, breaks down to form similar damaging compounds. 

Crispy may be even worse

Another problem with these types of meat is that they're usually cooked at higher temperatures which can create harmful molecules like heterocyclic amines, and aromatic hydrocarbons.

Like most things, the advice is moderation

News is full of hype, but the reality is these types of meat carry a very mild risk if consumption is also mild. Compared to other dangers the risk begins to look even smaller. The negative findings shouldn't be swept under the rug entirely, but the warnings don't mean you should stop eating any quantity. It just means if you're health conscious, you might want to watch your intake.

“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. You could try having fish for your dinner rather than sausages, or choosing to have a bean salad for lunch over a BLT”

The dilemma is that thousands of molecules are tied to cancer. Living is a cancer risk! Every year you live increases your likelihood of cancer. Taking every single warning to heart can also backfire, as science expands all the time. Dangers like sun exposure are still not entirely understood, and abstaining entirely isn't necessarily beneficial either. Understanding more about the biology of aging and working on how to fix the bigger problems is a far more effective strategy than restricting your bacon intake.

“The IARC says you can enjoy your yoga class, but don’t breathe air (class 1 carcinogen), sit near a sun-filled window (class 1), apply aloe vera (class 2B) if you get a sunburn, drink wine or coffee (class 1 and class 2B), or eat grilled food (class 2A). And if you are a hairdresser or do shift work (both class 2A), you should seek a new career.”

Read more at The Guardian