How Much Cancer Does Processed Meat Cause?

How Much Cancer Does Processed Meat Cause?
Colorectal cancer is our second leading cause of cancer death for men and women combined, after lung cancer. (Shutterstock)
Michael Greger
4/15/2022
Updated:
4/18/2022

In 2018, arguably the most prestigious cancer research institution in the world, the International Agency for Research on Cancer (IARC), within the World Health Organization, published their report on processed meat, concluding that foods like bacon, ham, hot dogs, lunch meat, and sausage are cancer causing, classifying processed meat as a Group 1 carcinogen. “These findings,” concluded the director of the agency, “further support current public health recommendations to limit intake of meat.” Critics questioned putting processed meat in the same carcinogenic classification as asbestos or tobacco. Or, as a pesticide company roughly put it, how can eating processed meat fall into the same category as mustard gas?

The classifications only relate to the strength of evidence that the agent causes cancer or not––not how much cancer. This does not mean that they are all equally dangerous. It’s safer to eat a sandwich filled with pastrami than plutonium, even though they are both Group 1 carcinogens––both substances known to cause cancer in people.

Okay, so just how dangerous is meat? The relative risk of colorectal cancer was 18 percent for every 50 grams a day. Okay, so what exactly does that mean? Well, 50 grams is about one hot dog, or two breakfast links, or two slices of Canadian bacon or ham. So, a daily sandwich with one or two slices of baloney would increase your colorectal cancer risk by 18 percent. But a half-pound pastrami on rye would bump it up more like 80 percent.

Okay, but what does the 18 percent increased risk really mean? One way to look at it is absolute risk versus relative risk. Assuming that the lifetime risk of colorectal cancer is about 5 percent (1 in 20), increasing your risk about 20 percent would only bump up your absolute risk of getting colorectal cancer from 5 percent to 6 percent. Now, on a population scale, an 18 percent drop in risk could mean about 25,000 fewer cases of colorectal cancer every year in the United States: 25,000 fewer families a year dealing with that diagnosis––if we swapped out the daily baloney sandwich for hummus, or chose veggie dogs instead. So, it all depends on how you look at it.

Colorectal cancer is our second leading cause of cancer death for men and women combined, after lung cancer. So, if you don’t smoke, colon and rectal cancer may be your greatest cancer nemesis. But we can drop the risk of getting it by about a fifth with a single dietary tweak: cutting a serving of processed meat out of our daily diet.

How does 18 percent increased cancer risk compare to other risky behavior? In my testimony before the Dietary Guidelines Scientific Committee, I made what may sound like a hyperbolic metaphor. I asked, “We try not to smoke around our kids; why would we send them to school with a baloney sandwich?” That is not hyperbole. According to the Surgeon General, living with a smoker increases your risk of lung cancer by 15 percent. So, breathing secondhand smoke day in and day out increases your risk of lung cancer almost as much as eating a serving of processed meat day in and day out increases your risk of colorectal cancer.

The meat industry responded by saying that the risks and benefits must be considered together before telling people what to eat or breathe. Think about all the baloney benefits. Lunch meat isn’t just about cancer, but convenience.

Indeed, processed meat isn’t just about cancer. An article railing against the World Health Organization’s “meat terrorism” cited the Global Burden of Disease studies comparing how many cancer deaths are caused by processed meat consumption, compared to tobacco or alcohol use. But if you look at the study they’re referencing, the 30-something thousand deaths attributable to higher processed meat intake are just the colorectal cancer deaths, and don’t also include the 100,000 deaths from diabetes, or the 400,000 deaths from heart disease. So, in actuality, we may be talking a half million deaths attributable to processed meat. And it’s not just colon and rectal cancer. If you look at the science since the IARC decision was published, processed meat may also increase the risk of prostate cancer, breast cancer, and pancreatic cancer.

Unfortunately, despite growing public health concerns about processed meat consumption, there have been no changes in the amount of processed meat consumed by U.S. adults over the last 18 years. Of course, it would have helped if the last Dietary Guidelines for Americans had happened to mention that processed meat was a carcinogen. An explicit and science-based statement on processed meat in the next Dietary Guidelines would certainly help. But the scientific committee made no such recommendation.

Sadly, even those diagnosed with colorectal cancer hardly improve their overall lifestyle after diagnosis, though that may be because “70 percent of cancer patients had never received nutrition advice from their [medical] providers during or after treatment.” That just blows me away.

“Despite the continued obfuscation of the issue by the meat industry—they learned well from the tobacco merchants—meat should continue to be a focus of public health action.” New York City is leading the way, passing legislation to ban processed meats from school meals. What a concept, not giving our kids carcinogens.

Meanwhile, the processed meat industry is trying to reformulate its products. It’s kind of like in the pharmaceutical area, where you try to mitigate the potential adverse effects of one drug by prescribing an additional drug. Like you could add fiber to hot dogs or something to try to counterbalance the risk, potentially reducing the cancer load by changing how it’s processed, rather than by banning processed meat altogether.

This story was originally published on the NutritionFacts.org site.
Michael Greger, MD, FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. He has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on “The Dr. Oz Show” and “The Colbert Report,” and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. This article was originally published on NutritionFacts.org
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