Eating processed meats can cause colorectal cancer, concludes a new report from the World Health Organization, while eating red meats may also raise risk for the disease.
The report, compiled by a Working Group of 22 experts across 10 countries on behalf of the World Health Organization's (WHO) International Agency for Research on Cancer (IARC), is published today in The Lancet Oncology.
Numerous studies have linked high consumption of red and processed meats with greater risk for colorectal cancer, or bowel cancer, with associations being so strong that they have influenced public health recommendations.
In 2011, for example, Medical News Today reported on a recommendation from the UK's Department of Health to reduce intake of red and processed meats from 90 g daily to 70 g daily to lower cancer risk.
This latest report supports recommendations to reduce intake of such foods, after finding that every 50 g of processed meats consumed daily - the equivalent to two slices of bacon - may raise the risk for colorectal cancer by 18%.
While the report authors note that the link between red meats and cancer risk was more difficult to establish, the studies they analyzed suggest every 100 g of red meat eaten daily may raise colorectal cancer risk by 17%.
The experts also identified a link between high intake of red meats and increased risk for pancreatic and prostate cancers, although to a lesser extent.
Diets high in processed meats 'may cause 34,000 deaths annually'
To reach their findings, the IARC Working Group reviewed more than 800 studies assessing the link between red and processed meats and numerous types of cancer.
Red meat was defined as any form of mammalian muscle meat, including beef, pork, lamb, mutton and goat. Processed meat was defined as any meat that has been subject to any processes that boost flavor or improve preservation, including salting, curing and smoking. Examples of processed meats include bacon, sausages and hot dogs.
The experts identified "sufficient evidence" from epidemiological studies that high intake of processed meats is carcinogenic to humans. In other words, there is strong evidence that a high intake of processed meats causes colorectal cancer.
Based on recent data from the Global Burden of Disease Project, the experts note that a diet high in processed meats may cause around 34,000 cancer deaths across the globe annually.
While the link between red meat intake and cancer was based on limited evidence, they state that diets high in red meats may cause around 50,000 deaths globally every year.
Commenting on the results of the review, Dr. Kurt Straif, head of the IARC Monographs Programme, says:
"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."
While the experts say their findings support recommendations to reduce intake of red and processed meats, they note that there is some nutritional benefit from such foods.
"Therefore," says Director of the IARC Dr. Christopher Wild, "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."
Previous studies have suggested there may be other negative health implications associated with high intake of red and processed meats. Last year, a study reported by MNT linked eating processed red meat to greater risk for heart failure, while another study suggested red meat consumption may raise the risk for Alzheimer's disease.