The World Health Organization (WHO) has deemed that processed meats — such as bacon, sausages and hot dogs — can cause cancer. In addition, the WHO says red meats including beef, pork, veal and lamb are “probably carcinogenic” to people.
A group of 22 scientists reviewed the evidence linking red meat and processed meat consumption to cancer, and concluded that eating processed meats regularly increases the risk of colorectal cancer. Their evidence review is explained in an article published in The Lancet. The conclusion puts processed meats in the same category of cancer risk as tobacco smoking and asbestos. This does not mean that they are equally dangerous, according to the International Agency for Research on Cancer (IARC) — the agency within the WHO that sets the classifications.
The IARC says that eating meat has known health benefits, but it also points out that the cancer risk increases with the amount of meat consumed. The IARC further says that high-temperature cooking methods (such as cooking meat in direct contact with a flame) produce more carcinogenic compounds. However, the group indicates there were not enough data to reach a conclusion about whether the way meat is cooked affects the risk of cancer.
A systematic literature review on colorectal cancer published in 2011 by the World Cancer Research Fund found a statistically significant, 16 percent increased risk of colorectal cancer associated with each 3.5 ounces of red and processed meat consumed per day. This is an amount of meat roughly equivalent in size to a deck of cards. In its new evaluation, the IARC offered a different risk assessment: It concluded that eating about 1.8 ounces of processed meat daily will increase the risk of colorectal cancer by about 18 percent. This is relative risk; the chances of developing colorectal cancer are fairly low to begin with.
The Lancet paper points out that red meat also contains “high biological-value proteins and important micronutrients such as B vitamins, iron and zinc.”
The IARC’s conclusions evoked strong responses, with significant resistance from the meat industry and from some environmental groups calling for warning labels on meat. The North American Meat Institute was quick to point out that lots of research points to the benefits of red meat consumption.
“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,” writes Barry Carpenter, president of the North American Meat Institute, in a statement in response to the new WHO classification. Carpenter says it’s important to put this new classification in context. “IARC’s panel was given the basic task of looking at hazards that meat could pose at some level, but was not asked to consider any off-setting benefits, like the nutrition that meat delivers or the implications of drastically reducing or removing meat from the diet altogether,” the statement concludes.