Processed Meats Associated With Colorectal Cancer

colorectal cancer

Christopher Wild, PhD

The International Agency for Research on Cancer (IARC) has classified processed meat as carcinogenic to humans (Group 1) and red meat as probably carcinogenic to humans (Group 2A), according to a press release¹from the agency.

According to the release, the IARC Monographs Programme brought together a working group of 22 experts from 10 countries to investigate how red and processed meats affect humans. The group found strong mechanistic evidence supporting a carcinogenic effect for the consumption of both meat types, though the IARC does clarify that the link between cancer and processed meats is much stronger than the link for red meat.

This evidence was mainly associated with colorectal cancer, though associations for pancreatic cancer and prostate cancer were also observed. Findings were based on "limited evidence" in the conclusion for red meat and "sufficient evidence" for processed meat.

“These findings further support current public health recommendations to limit intake of meat,” said Christopher Wild, PhD, 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.”

Experts involved in the study¹concluded that consumption of 50g of processed meat eaten on a daily basis increases the risk of colorectal cancer by 18%. A ratio of red meat consumption to cancer risk was not drawn.

The impetus for this study stems from an international advisory committee that met in 2014, which recommended red meat and processed meat as high priorities for evaluation by the IARC Monographs Programme. The committee's recommendation was based on epidemiological studies suggesting a potential link between risk of several cancers and high consumption of red meat or processed meat.

“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 Kurt Straif, MD PhD MPH, head of the IARC Monographs Programme in the press release. “In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance.”

According to the press release, 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.

Academic research organization, Global Burden of Disease Project, estimates that approximately 34,000 cancer deaths worldwide on a yearly basis are attributable to diets containing high levels of processed meats.²

According to a Q&A posted on the IARC website, red meat is defined as mammalian muscle meat, including, beef, veal, pork, lamb, mutton, horse, and goat. Processed meat refers to meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation. Examples of processed meat include hot dogs (frankfurters), ham, sausages, corned beef, and biltong or beef jerky, as well as canned meat and meat-based preparations and sauces.²

References

1. WHO. International Agency for Research on Cancer. http://www.iarc.fr/. IARC monographs evaluate consumption of red meat and processed meat. http://www.iarc.fr/en/media-centre/pr/2015/pdfs/pr240_E.pdf. Accessed October 28, 2015.
2. WHO. International Agency for Research on Cancer. Q&A on the carcinogenicity of the consumption of red meat and processed meat. http://www.iarc.fr/. 2015. http://www.iarc.fr/en/media-centre/iarcnews/pdf/Monographs-Q&A_Vol114.pdf. Accessed October 28, 2015.