The World Health Organization (WHO) declared today that red meat falls into the category of compounds that are “probably carcinogenic to humans,” Group 2A, while processed meats fall into the graver Group 1, compounds that are “carcinogenic to humans,” along with cigarette smoke and asbestos. (Note: this doesn’t mean meat is as bad for you as smoking, just that there’s enough evidence now to put in this category.) The evidence that various types of meat are linked to cancer has been mounting in recent years, so the WHO’s decision doesn’t come as a complete shock. But for many who have resisted making dietary changes, the fact that the foods how fall along with the most serious carcinogens may help spark some change.
Based on the existing studies, the experts calculated the effects of eating increasing amounts of red or processed meat on a person’s cancer risk. For instance, every additional 50-gram portion of processed meat per day may increase the risk of colorectal cancer by 18%.
“For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed,” says Dr Kurt Straif, Head of the IARC Monographs Programme. “In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance.”
The evidence was less dramatic for red meat, but the risk still there, said the WHO, particularly in regard to colorectal cancer. A smaller risk is also thought to exist between red meat and pancreatic and prostate cancers.
“These findings further support current public health recommendations to limit intake of meat,” says Christopher Wild, Director of IARC. “At the same time, red meat has nutritional value. Therefore, these results are important in enabling governments and international regulatory agencies to conduct risk assessments, in order to balance the risks and benefits of eating red meat and processed meat and to provide the best possible dietary recommendations.”
Red meat is defined by the WHO as any muscle meat from a mammal, including beef, veal, pork, lamb, mutton, horse, and goat. Processed meat includes hot dogs, ham, sausages, corned beef and beef jerky, as well as canned meat, “meat-based preparations,” and sauces. The WHO experts add that high-temperature cooking methods (especially where charring is the product) may create compounds that additionally increase the carcinogenic properties of meat, but more research is needed here.
The meat industry is not likely very happy about the new designations, and has already voiced some disapproval of the WHO’s new report. “Cancer is a complex disease that even the best and brightest minds don’t fully understand,” says Shalene McNeill, the Executive Director, Human Nutrition Research at National Cattlemen’s Beef Association. “Billions of dollars have been spent on studies all over the world and no single food has ever been proven to cause or cure cancer. The opinion by the IARC committee to list red meat as a probable carcinogen does not change that fact. The available scientific evidence simply does not support a causal relationship between red or processed meat and any type of cancer.”
However, as the WHO experts point out, although the real-world evidence is less strong, the cellular mechanisms behind the association between meat and cancer are well-understood. “In the case of red meat, the classification is based on limited evidence from epidemiological studies showing positive associations between eating red meat and developing colorectal cancer as well as strong mechanistic evidence.”
Time will tell how the new designations will affect our dietary habits. Doctors will probably begin warning patients about the connection a little more actively now. But balance is always a good thing: Eating red or processed meats every day or multiple times a day is likely not very wise. But perhaps a little red meat now and then is not such a bad thing in the grander scheme of things.
