Monday (October 26, 2015) the World Health Organization suggested it would be good to limit the amount of red and processed meat we consume. There has been quite a firestorm in the media declaring “red meat causes cancer”.
That’s not actually what the W-H-O said in its press release. It actually classified the consumption of red meat as “probably” carcinogenic to humans. Going on to point out that processed meats, things like ham & sausage or hotdogs & corned beef, if eaten every day does increase the chance of getting colorectal cancer by 18%.
Again - red meat, steaks, pork chops and the like, “probably carcinogenic” but the 800 studies reviewed were inconclusive as a whole; processed meat - “carcinogenic”, but you’d need to eat about two ounces of it every day to increase your chance of getting colorectal cancer by 18%.
So, what does W-H-O mean by “probably carcinogenic”? Fortunately the press release, which you can find online, has links to the classifications. Red meat falls into group 2A: The agent is probably carcinogenic to humans.
Here’s the definition verbatim - “This category is used when there is limited evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in experimental animals. Limited evidence means that a positive association has been observed between exposure to the agent and cancer but that other explanations for the observations (technically termed chance, bias, or confounding) could not be ruled out.”
Processed meats are in Group 1: The agent is carcinogenic to humans. Again here’s the definition: “This category is used when there is sufficient evidence of carcinogenicity in humans. In other words, there is convincing evidence that the agent causes cancer. The evaluation is usually based on epidemiological studies showing development of cancer in exposed humans. Agents can also be classified in Group 1 based on sufficient evidence of carcinogenicity in experimental animals supported by strong evidence in exposed humans that the agent has effects that are important for cancer development.”
W-H-O happens to put asbestos exposure and smoking tobacco into Group 1, however, the processed meat paper work explains this does NOT mean these are all equally dangerous. The classifications describe the strength of the scientific evidence (what the research reports studied say) rather than assessing the risk.
How dangerous is processed meat, then? WHO, in the paperwork, points to estimates by University of Washington’s Global Burden of Disease Project. It is an independent academic research organization that attributes about 34,000 cancer deaths per year worldwide to diets high in processed meat. By comparison the Center for Disease Control estimates 6 million people die from tobacco causes worldwide; 480,000 in the United States from smoking cigarettes. Download Audio