The latest cancer report from the World Health Organization provides persuasive evidence that eating meat can cause cancer, but the risk is very small for most people. ADVERTISING The latest cancer report from the World Health Organization provides persuasive evidence
The latest cancer report from the World Health Organization provides persuasive evidence that eating meat can cause cancer, but the risk is very small for most people.
A research arm of the WHO, known as the International Agency for Research on Cancer, concluded in a paper published Monday that processed meats — like bacon, ham and hot dogs — are a cause of colon cancer and conceivably of stomach cancer, although that link has not been pinned down. This is because processing the meat by curing, smoking, fermentation or other methods generates chemicals that are carcinogens or suspected carcinogens.
The agency also said that red meats like beef and pork are probably a cause of colorectal cancer and possibly a cause of pancreatic and prostate cancer.
The agency found “sufficient evidence” (not just a weak association) that processed meat can cause cancer, but the risk from smoking is many orders of magnitude greater, according to Dr. John Ioannidis, the chairman of disease prevention at Stanford University. “I think it’s very important that we don’t terrorize people into thinking that they should not eat any red meat at all.”
Tobacco smoking causes about a million cancer deaths a year worldwide; alcohol adds another 600,000 annual cancer deaths. Diets high in processed meat cause about 34,000 cancer deaths globally, the agency calculated.
The report was approved by a majority of the 22 scientists from 10 countries who reviewed more than 800 studies of cancer in humans at the request of the agency, but the panel failed to reach a unanimous consensus, reflecting sharp differences of opinion among experts.
The panel’s conclusions were based primarily on epidemiological studies linking what people ate with cancers they developed later. Often such studies can’t prove a causal link. But the agency said that the evidence that processed meats caused cancer was as strong as the evidence that tobacco and asbestos cause cancer.
While the absolute risk of eating processed meats like sausage or corned beef is low, people who eat a lot every day can drive up their risks. The link between cancer and red meat is less persuasive. It was based on limited evidence from epidemiological studies in which other factors could not be ruled out.
The agency’s conclusions are consistent with the findings and recommendations issued in recent years by the American Cancer Society and the World Cancer Research Fund. An expert committee advising the federal government on what to include in the forthcoming Dietary Guidelines for Americans recommended that people should follow diets “lower in red and processed meat.”
The final version of the guidelines should provide a more precise idea of how much processed meat and red meat is appropriate.
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