What's The Beef?
Get the facts about meat consumption and cancer risk.
By Brenda Conaway
Given the October 2015 report from the World Health Organization (WHO) about the cancer hazards of eating red and processed meats, what’s a meat eater to do? Just how serious is the cancer risk from these foods?
“The evidence about red meat and processed meat and cancer has been around a long time,” says Mariana C. Stern, a cancer epidemiologist at the Keck School of Medicine of the University of Southern California in Los Angeles, and a member of the working group responsible for the report. On behalf of the International Agency for Research on Cancer (IARC), WHO's cancer agency, the expert panel concluded that there was sufficient evidence that processed meat—which includes cold cuts, sausages and hot dogs—causes colorectal cancer in people. The working group also concluded that red meat—including beef, lamb, veal, goat and pork—probably causes colorectal cancer.
Though it’s still unclear how processed and red meat increases cancer risk, research has pointed to three mechanisms. Preservation techniques can introduce nitrates and nitrites, which react with compounds called amines in meat and form cancer-causing agents that can attack DNA in the cells of the intestines, says Stern. Heme, an iron-containing compound that gives red meat its color, can also cause DNA damage in the intestines. In addition, cooking meat over high heat, such as in a pan or over a grill, causes carcinogens to form in the meat, says Stern.
What’s been confusing to some, Stern says, is that the IARC labeled processed meats as a Group 1 carcinogen—the same category as tobacco. "The level of risk associated with processed meat is much lower than for tobacco,” Stern says.
While the report didn't make specific nutritional recommendations, existing guidelines suggest people should limit red meat and avoid processed meat. “A more positive spin,” Stern says, “is to … fill your plate with plant-based foods, and a little bit of meat. Make the portion small so you can enjoy it, and fill up on other things that are nutritious and healthy and protective.”