How to Digest the WHO's Red and Processed Meat Cancer Claims

UW-Madison food scientists explain the three common culprits behind the increased cancer risk from processed meats.Madison, Wisconsin – In late October, the World Health Organization (WHO) suggested that each 50 gram serving of processed meat, which is less than two average slices of bacon, increases the risk of developing colorectal cancer by 18 percent.

They also said that a 100 gram serving of red meat could increase your colorectal cancer risk by 17 percent, but that the evidence was not as strong for red meat.

‘Red meat’ is defined as and meat that’s dark red before it is cooked. Think lamb and beef, but this group also includes pork, ‘the other white meat.’ (Why? It’s a livestock product.) ‘Processed meat’ is any meat (think beef, chicken, fish and everything in between) that has been cured, salted, smoked, shaped, cooked, preserved or otherwise prepared.

Okay, but what is it exactly in these foods that is being blamed for this increased cancer risk? Common culprits include nitrates, nitrites, and carcinogens from cooking at high temperatures.

Nitrates and Nitrites

These are salts added to meat to preserve it and more importantly protect against some pathogens like botulism. These compounds can, under certain circumstances, turn into carcinogenic compounds in the body that have been shown to damage DNA. (In the average diet, about 80 percent of nitrates come from vegetables like spinach, beets and radishes. Also, let’s not forget that celery juice is often used to “naturally” cure meat because celery is very high in nitrates.)


When meat is fried, roasted or grilled at high temperatures, the meat produces more HCAs and PAHs (heterocyclic amines and polycyclic aromatic hydrocarbons, respectively), two classes of compounds that studies have shown cause cancer in animals. Pan-frying meats like you did to Sunday’s bacon make them more susceptible too, since pan frying requires high temperatures. Cooking poultry and fish at these same temperatures produces HCAs and PAHs as well.

But preparation and cooking lead us to perhaps the first guffaw for Andrew Milkowski, PhD, an adjunct professor in animal sciences at the University of Wisconsin-Madison and member of the Food Research Institute. Milkowski, who’s been closely following the WHO’s review of red and processed meats and their protocols, would posit you this: if you’re going to buy some ground beef and bring it home to cook it, what are you going to do with it before it hits the grill?

“You’re probably going to season it in one way or another and then cook it. What you’re seeing in processed meats is essentially the same thing,” he says. “They buy it, blend it with seasoning ingredients like salts and starches and other seasonings, and then they’re going to cook it. And meat processors are cooking – for the most part – under much better controlled conditions and at lower temperatures than consumers would when throwing meat on the backyard grill.”

So does that mean that it could be one of the other common ingredients used by consumers and food processors alike that’s causing problems? Milkowski doubts it.

“Consumers shouldn’t be worried about ingredients in processed meats. All of the ingredients that are going into the processed meats we consume have gone through vetting and safety checks,” says Milkowski. “The message that I would preach is one of moderation and variety, and don’t get overly concerned about particular things. From the standpoint of any individual, you can’t really quantify and say that if you eat this, then you’re going to get cancer. It’s not possible with our knowledge base today.”

That might be a lot to swallow, so let’s simplify. Trying to stay healthy? Milkowski would have you heed a very modest warning: don’t overdo it with any single food, processed meats included.

“Eat meat and everything else in moderation, keep a good bodyweight, and stay active,” he says. “You can eat bacon; just don’t go eating a pound of bacon a day every day of the week.”