Stop panicking about cancer risk from processed and red meat, experts say

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Stop panicking about cancer risk from processed and red meat, experts say

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Sausages, bacon and egg being fried.
Image: Nick Ansell/PA Wire/Associated Press

On Monday, the World Health Organization’s cancer research agency exploded into the news with a report claiming that processed meats cause cancer and red meats probably do as well. The report was released by the International Agency for Research on Cancer (IARC) and was authored by a panel of 22 experts, who compiled it using data from more than 800 studies on the link between meat and cancer.

It’s an admittedly dismaying headline, particularly in the United States, which has one of the highest levels of meat consumption in the world — but experts are cautioning that it’s no cause for hysteria.

In fact, there have been so many misconceptions generated by the news that the WHO released a statement on Thursday, including the following clarifying message:

“WHO has received a number of queries, expressions of concern and requests for clarification following the publication of a report from the International Agency for Research on Cancer (IARC) relating to processed meat and colorectal cancer. … IARC’s review confirms the recommendation in WHO’s 2002 Diet, nutrition and the prevention of chronic diseases report which advised people to moderate consumption of preserved meat to reduce the risk of cancer. The latest IARC review does not ask people to stop eating processed meats but indicates that reducing consumption of these products can reduce the risk of colorectal cancer.”

In other words, not much, if anything, has changed when it comes to the WHO’s health recommendations.

Here are a few more points that are important to understand before making a hasty leap into vegetarianism.

Why the report seems so scary — and why it’s not actually as bad as it sounds

The WHO report includes two details in particular that may generate worry if misunderstood.

First, the report classifies processed meat as a Group I carcinogen, which many media outlets have noted puts it in the same category as cigarettes. That sounds pretty terrifying, given that smoking is responsible for 90% of all lung cancer cases and causes nearly one in every five deaths in the U.S., according to the Centers for Disease Control and Prevention.

But not all Group I carcinogens carry the same risk. The classification simply means that the substance has been shown to be carcinogenic. (Red meat, for the record, has been classified in Group 2A, which means that it’s probably — but not definitely — carcinogenic.)

Meat and Cancer

Steaks and other beef products are displayed for sale at a grocery store in McLean, Virginia in 2010.

Image: J. Scott Applewhite/Associated Press

As far as the actual cancer risk associated with processed meat — the report’s second misunderstood detail — the WHO said that eating 50 grams of processed meat daily (that’s about the equivalent of a couple of sausages per day) increases the risk of colorectal cancer by 18%.

But it’s important to understand that this is a relative risk, not an absolute risk, cautions Jonathan Schoenfeld, an assistant professor at Harvard Medical School’s Department of Radiation Oncology.

The statistic doesn’t mean that eating 50 grams of processed meat daily causes you to have an 18% total chance of developing cancer — it means you’re 18% more likely to develop cancer relative to whatever your initial, absolute risk already was. For example, if you had a 10% risk of developing colon cancer to begin with, and you ate 50 grams of processed meat every day, your risk would increase by 18%.

Eighteen percent of 10% is 1.8% — so your total risk would increase to 11.8%. That’s not trivial, but not a staggering rise, either.

In contrast, smoking is thought to increase the risk of developing lung cancer by about 25 times. That’s the same as saying the risk increases by 2,500%.

So while increasing your cancer risk by any amount is nothing to sneeze at, an increase of 18% is ”moderate” in comparison to some other carcinogens, Schoenfeld says. What may be important is evaluating your absolute risk of developing cancer — and that depends on a variety of different influences.

Many factors can affect your risk of developing cancer

The WHO specifically links processed meat to an increased risk of colorectal cancer. So if you’re worried about your processed meat intake, it may be a good idea to evaluate your risk of developing this type of cancer to begin with. Diet is one factor that can increase the risk, but it’s not the only one — nor is it even the most important.

The biggest factor that increases a person’s risk of colorectal cancer is age, says Frank Berger, director of the University of South Carolina’s Center for Colon Cancer Research.

“The vast majority of colon cancers occur in people over 50,” he says. So if you’ve reached this age, getting screened would be recommended even if you’re a vegetarian.

Tobacco and alcohol use are other risk factors that are associated with a wide variety of different cancers, Schoenfeld says. Lack of exercise has also been associated with an increased cancer risk, he says, and certain preexisting health conditions, such as inflammatory bowel disease, could also add to the danger of colorectal cancer, specifically.

World Health Organization Clarification

In response to some of the misconceptions about the report, the WHO issued a series of tweets containing answers to many of the public’s most common questions. Many of the answers came from a Q&A that the IARC issued alongside its report on Monday. Here are some of the top questions and answers:

Q: What is processed meat? https://t.co/NvCefcAPLC pic.twitter.com/uVC7LhCzoW

— WHO (@WHO) October 27, 2015

Q: Processed meat was classified as Group 1, carcinogenic to humans. What does this mean? https://t.co/NvCefcAPLC pic.twitter.com/BJGyX7uONu

— WHO (@WHO) October 27, 2015

Q: Does it mean that consumption of processed meat is as carcinogenic as tobacco smoking and asbestos? pic.twitter.com/YPOFh0RGfp

— WHO (@WHO) October 27, 2015

How your diet should change — if at all

The obvious question that remains is whether it’s best to cut out all meat in order to avoid the increased risk of certain types of cancer.

The answer depends on the individual. As Berger and Schoenfeld pointed out, there are many other influences, both environmental and genetic, that can affect a person’s risk of developing cancer.

“There are plenty of people who eat a very healthy diet, no red meat and plenty of fresh vegetables, and still get cancer,” Berger says. “There are plenty of people who eat bacon every day and do not get cancer.” So cutting out meat entirely doesn’t guarantee you won’t develop cancer — it just means the risk may be slightly smaller.

In general, it’s a good idea to simply be moderate with your diet, Schoenfeld says. So if you’re a person who eats red or processed meat every day, you don’t necessarily have to cut it all out. You might just cut back a little. And if you’re a person who already has a higher-than-average cancer risk, thanks to other factors, then it may be a good idea to cut back a little more than you otherwise would.

That’s not to say there isn’t a case for vegetarianism, or at least a significantly reduced meat consumption. High red meat consumption has also been associated with other health problems, including heart disease, diabetes and obesity).

A more vegetable-heavy diet is good for the environment as well. But if that’s not your priority, you can probably rest easy that consuming a moderate amount of meat isn’t signing a death warrant.

“I think people should just take this in a larger context of overall risk — that the 18% [risk] for each individual person is likely quite small, and that’s with a daily consumption of a pretty significant quantity of meat,” Schoenfeld says. “So for all the people who consume less, and for people who can do other things to modify their risk, I don’t think this should change lifestyle to the point where meat becomes your number one focus of maintaining good health.”

Chelsea Harvey is a freelance journalist specializing in science, health and environmental reporting.

Other things that may raise your risk of cancer

  1. Things-that-cause-cancer-01

    Being a hairdresser or barber

    IARC Group 2A – “Probably carcinogenic” to humans due to exposure to chemicals that may cause cancer.

    Image: Matthias Drobeck/Westend61/Corbis
  2. Things-that-cause-cancer-02

    Working with dry cleaning

    IARC Group 2B – “Possibly carcinogenic to humans” due to exposure to chemicals.

    Image: moodboard/Corbis
  3. Things-that-cause-cancer-03

    Frying foods and ’emissions from high-temperature’

    IARC Group 2A – “Probably carcinogenic to humans”

    Image: 145/Ocean/Corbis
  4. Things-that-cause-cancer-05

    Drinking hot mate

    IARC Group 2A – “Probably carcinogenic to humans”

    Image: Kelly-Mooney Photography/Corbis
  5. Things-that-cause-cancer-07

    Working the late shift

    IARC Group 2A – “Probably carcinogenic to humans” because “shiftwork” can interrupt a person’s natural circadian rhythms.

    Image: Jade/Blend Images/Corbis
  6. Things-that-cause-cancer-09

    Working as a carpenter

    IARC Group 2B – “Possibly carcinogenic to humans”

    Image: Jetta Productions/Blend Images/Corbis
  7. Things-that-cause-cancer-10

    Alcoholic drinks

    IARC Group 1 -“Carcinogenic to humans”

    Image: Emma Innocenti/Corbis