An international panel of experts convened by the World Health Organization concluded Monday that eating processed meat like hot dogs, ham and bacon raises the risk of colon cancer and that consuming other red meats “probably” raises the risk as well. But the increase in risk is so slight that experts said most people should not be overly worried about it.
The report placed processed meat into its Group 1 category, which means the panel found “sufficient evidence” that it could cause cancer. While other substances in this group include alcohol, asbestos and tobacco smoke, they do not all share the same level of hazard. The risk attributed to smoking, for example, is many orders of magnitude greater than the risk associated with eating red meat, said Dr. John Ioannidis, the chairman of disease prevention at Stanford University.
“I think it’s very important that we don’t terrorize people into thinking that they should not eat any red meat at all,” said Dr. Ioannidis, who was not involved in the new report. “There’s some risk involved, but it’s much less than smoking or alcohol. I think it would be an exaggeration to say based on this that no one should be eating red or processed meat.”
Smoking causes a roughly 20-fold increase in a person’s risk of developing lung and other types of cancer, and every year it results in about a million deaths worldwide. In comparison, a person’s risk of colorectal cancer rises by a factor of about 1.1 or 1.2 for every serving of processed meat consumed per day. This means that based on the report, diets high in processed meat could be expected to contribute to about 30,000 deaths per year across the globe, though the true number could also be far less, Dr. Ioannidis said.
“There is still a lot of uncertainty,” he added.
The committee that issued the new report, the International Agency for Research on Cancer, consists of 22 public health, cancer and other experts from 10 countries. The group, which reviewed 800 studies on cancer in humans, acts as an adviser to the World Health Organization, focusing on environmental and lifestyle factors that may contribute to the disease.
Since 1971, the group has evaluated more than 900 such factors as part of its “monographs” program, assigning each factor to one of five different classification groups based on the likelihood of it playing a role in cancer.
About 120 of these factors have been characterized as carcinogenic to humans and assigned to the agency’s Group 1 category. The other groups range in classification from “probably carcinogenic,” “possibly carcinogenic,” and then “not classifiable” and finally “probably not carcinogenic.”
