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Red meat could raise cancer risk, conclude experts

Both red and processed meat heighten risk

Adrian O'Dowd

Monday, 26 October 2015

Eating red meat as well as processed meat could raise the risk of developing cancer, conclude experts of a large international study* published today in The Lancet Oncology journal.

The International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization (WHO), evaluated the carcinogenicity of the consumption of red meat and processed meat.

Processed meat is defined as meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavour or improve preservation, and includes hot dogs (frankfurters), ham, sausages, corned beef, and canned meat.

After reviewing the accumulated scientific literature, a working group of 22 experts from 10 countries convened by the IARC Monographs Programme classified the consumption of red meat as probably carcinogenic to humans, 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 and prostate cancer.

The review also decided to classify processed meat as carcinogenic to humans, based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer.

Consumption of meat varies greatly between countries, but in general, more people tend to eat red meat overall than processed meat.

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 carried out over the past 20 years.

From their analysis, the experts concluded that each 50g portion of processed meat eaten daily increased the risk of colorectal cancer by 18%.

Dr Kurt Straif, head of the IARC Monographs Programme, said: “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.

“In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance.”

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

Meat Advisory Panel member Professor Robert Pickard, emeritus professor of neurobiology at the University of Cardiff, said: “Looking at the report itself I am very surprised by IARC’s strong conclusion on categorising processed red meat as definitely and red meat as being probably carcinogenic to humans given the lack of consensus within the scientific community and the very weak evidence regarding the causal relationship between red meat and cancer.

“Avoiding red meat in the diet is not a protective strategy against cancer. The top priorities for cancer prevention remain smoking cessation, maintenance of normal body weight and avoidance of high alcohol intakes. Red meat has a valuable role within a healthy, balanced diet thanks to its high protein content and rich nutritional composition.”

Professor Tim Key, Cancer Research UK's epidemiologist at the University of Oxford, said: “We've known for some time about the probable link between red and processed meat and bowel cancer, which is backed by substantial evidence.

"This decision doesn't mean you need to stop eating any red and processed meat, but if you eat lots of it you may want to think about cutting down. Eating a bacon bap every once in a while isn't going to do much harm - having a healthy diet is all about moderation.”


* Bouvard V, et al. Carcinogenicity of consumption of red and processed meat. The Lancet Oncology, October 2015. DOI: 10.1016/S1470-2045(15)00444-1

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