The Link Between Meat and Cancer: MSK Experts Explain the Headlines

You’ve probably seen the attention-grabbing headlines this week: Bacon causes cancer! But what’s the real story behind the news?

Earlier this week, the International Agency for Research on Cancer (IARC), the cancer arm of the World Health Organization, announced that it had classified processed meat as a carcinogen, or cancer-causing agent, “based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer.” It also classified red meat as a probable carcinogen based on limited evidence linking its consumption to cancer and “strong mechanistic support supporting a carcinogenic effect.”

In the report, a group of 22 experts from ten countries concluded that every 50-gram portion of processed meat eaten per day — the equivalent of a hot dog or two or three strips of bacon — increased the risk of colorectal cancer by 18 percent.

Experts from Memorial Sloan Kettering put this news into perspective.

“This announcement didn’t come as a big surprise to most of us,” says MSK gastroenterologist Robin Mendelsohn. “We’ve known for a long time that obesity is associated with cancer, so there’s a direct link between eating high-fat, high-calorie foods like meat and an increased cancer risk.”

Medical oncologist Clifford Hudis, Chief of MSK’s Breast Cancer Medicine Service, Vice President for Government Relations, and Chief Advocacy Officer, adds that foods high in preservative salts, such as processed meats, have been associated with gastrointestinal cancers for more than 100 years. He also notes that the refrigerator, by allowing us to eat things that use less of these specific salts, contributed to a decline in stomach cancer in the last century.

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In addition, many processed meats like sausage and ham are smoked, which may further increase the number of carcinogenic compounds in them.

For other, nonprocessed red meat, the mechanism by which eating them may lead to cancer is not entirely clear, Dr. Mendelsohn says, but many of these foods also tend to be high in fat and calories.

Speaking about the IARC findings, Dr. Hudis explains, “an 18 percent increased risk is considered real but modest from a public-health standpoint, compared to cigarettes and tobacco, which increase the risk of lung cancer 800 percent or more. Some of the elevated risk may reflect the association of meat consumption with increased weight.”

“Given that much larger increases in risk are seen with tobacco as one example,” he says, “red meat is not the biggest issue. There are great reasons to avoid meat, including its high calorie content. The global issue we face is rising rates of obesity.”  And like tobacco use, obesity is a modifiable risk factor for cancer, which means that people may be able to avoid increased risk by maintaining a healthy weight throughout their life.

“Obesity will soon replace tobacco as the leading modifiable risk factor for cancer, at least in Western countries, ” Dr. Hudis says, noting a policy statement issued by the American Society of Clinical Oncology earlier this year.

The bottom line: Experts agree that the most important thing to focus on is a healthy, balanced diet that includes lots of fruits and vegetables, as well as exercising regularly and keeping your weight under control. A diet low in meat can be an easy way to achieve this goal, says Dr. Hudis.

“Anytime you choose to eat something healthy, that’s better, but I like to eat a steak or a hot dog once in a while, and that’s OK. Everything in moderation,” says Dr. Mendelsohn.