The International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization (WHO), has evaluated the carcinogenicity of the consumption of red meat and processed meat. After reviewing the accumulated scientific literature, a Working Group of 22 experts from 10 countries convened by the IARC Monographs Program concluded that processed meat should be classified as carcinogenic to humans (Group 1), based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer. The experts concluded that each 50 g portion of processed meat eaten daily increases the risk of colorectal cancer by 18%.
While tobacco smoking and asbestos are also both classified in Group 1 (carcinogenic to humans), it should be noted that this does not mean that they are equally dangerous. According to an IARC Q&A document, “the IARC classifications describe the strength of the scientific evidence about an agent being a cause of cancer, rather than assessing the level of risk.”
The IARC also classified the consumption of red meat as probably carcinogenic to humans (Group 2A), based on limited evidence that the consumption of red meat causes cancer in humans and strong mechanistic evidence supporting a carcinogenic effect. This association was observed mainly for colorectal cancer, but associations were also seen for pancreatic cancer and prostate cancer.
“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,” said Kurt Straif, Head of the IARC Monographs Program. “In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance.”
The IARC Working Group considered more than 800 studies that investigated associations of more than a dozen types of cancer with the consumption of red meat or processed meat in many countries and populations with diverse diets. The most influential evidence came from large prospective cohort studies conducted over the past 20 years.
”These findings further support current public health recommendations to limit intake of meat,” said 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.”
The North American Meat Institute (NAMI) responded that the IARC’s conclusion “defies both common sense and numerous studies showing no correlation between meat and cancer and many more studies showing the many health benefits of balanced diets that include meat. Scientific evidence shows cancer is a complex disease not caused by single foods and that a balanced diet and healthy lifestyle choices are essential to good health.”
“IARC’s decision simply cannot be applied to people’s health because it considers just one piece of the health puzzle: theoretical hazards,” said Betsy Booren, NAMI vice president of scientific affairs. “Risks and benefits must be considered together before telling people what to eat, drink, drive, breathe, or where to work.”
