For a long time, doctors and other health professionals have warned about the dangers of eating too much red and processed meat and for a long time the debate has raged on between those who love their bacon, steak and sausages and those who lean toward what they see as a more moderate and healthy diet.
Now, the International Agency for Research on Cancer (IARC) — the branch of the World Health Organization (WHO) that heads research into the disease — has officially appraised the potential carcinogenic properties of meat — and the results make uncomfortable reading for meat-lovers.
The IARC report classifies red meat — that's all varieties of "mammalian muscle meat, such as beef, veal, pork, lamb, mutton, horse and goat" — as "probably carcinogenic to humans." This means the advice is based on limited knowledge — though observation seems to show a clear correlation between consumption of red meat and cancer, as yet no direct cause has been outlined. On the other hand, processed meat — that is "meat that has been transformed through salting, curing, fermentation, smoking or other processes to enhance flavor or improve preservation" is described emphatically as "carcinogenic to humans."
Most processed meats contain pork or beef, the researchers say, but so-called processed meats — for example, hotdogs, ham, sausages, corned beef, biltong or beef jerky, canned meat and even meat-based preparations and sauces — can be made using other forms of red meats as well as poultry, offal or meat byproducts such as blood. According to a study released by the National Institutes of Health (NIH) in 2011: "Despite a shift toward higher poultry consumption… [t]wenty-two percent of the meat consumed in the U.S. is processed."
The report, the organization say, is based on strong evidence of a link based on clinical observations. A group of 22 experts from 10 countries was assembled by the IARC to review the currently available scientific literature. Looking at more than 800 studies that covered a dozen types of cancer and the consumption of red meat or processed meat in a number of worldwide populations with diverse diets, the researchers concluded that though the levels of consumption for red and processed meat varies widely around the world, each 50-gram portion (that's 1.8 ounces or about 6 slices) of processed meat eaten daily means an 18 percent increase in the risk of colorectal cancer. Red meat was also linked to colorectal cancer as well as cancer of the pancreas and prostate. According to the North American Meat Institute, "American men on average eat 6.9 oz. of meat per day and women eat 4.4 oz."
This may not seem to add up when you look at the figures — according to the Global Burden of Disease Project, an independent academic research organization, 34,000 deaths a year are attributable to diets high in processed meat — but the danger to health becomes more significant depending on the quantity in your diet. "For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small," says Dr. Kurt Straif, head of the IARC Monographs Programme, "but this risk increases with the amount of meat consumed." Straif says, however, that it is the ubiquity of meat consumption that makes understanding its effect so vital. “In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance.”
Indeed, says the IARC, although the risks are small, the advice is important because "many people worldwide eat meat and meat consumption is increasing in low- and middle-income countries." According to Dr. Christopher Wild, the director of IARC, the finding "further supports current public health recommendations to limit intake of meat." At the same time, he says, "red meat has nutritional value. Therefore, these results are important in enabling governments and international regulatory agencies to conduct risk assessments, to balance the risks and benefits of eating red meat and processed meat and to provide the best possible dietary recommendations."
Since the storm of reaction to the new report broke this week, some voices have claimed the advice is old news and unworthy of the "panic" the IARC seem to advocate. Although panic is rarely a good solution to any problem, it is true that an advisory committee met last year and decided that red meat and processed meat were "high priorities for evaluation." Nevertheless, four years ago, the American Cancer Society and eight years ago the National Institutes of Health were warning of the "association between consumption of red and processed meats and cancer, particularly colorectal cancer."
What we should take away from the IARC announcement is the fact that these warnings are still important. Just because pre-existing data has been collated and reissued does not make that information any less vital — good advice is still good advice.