Very hot drinks "probably" cause cancer, the UN's cancer research agency announced today, but that doesn't include coffee. The International Agency for Research on Cancer (IARC), part of the World Health Organization, said on Wednesday that coffee can not be classified as a carcinogen, based on a review of more than 1,000 studies. Drinking very hot beverages likely causes cancer of the esophagus, the IARC said, though consuming coffee and herbal drinks at "normal serving temperatures" carries no cancer risk. A summary of the IARC's findings was published on Wednesday in The Lancet Oncology.
The WHO classified coffee as a possible carcinogen in 1991, for its potential link to bladder cancer, though studies conducted since then have found no connection. The American Institute for Cancer Research says coffee may even help protect against cancer. The IARC brought together 23 scientists to review studies on the cancer-related properties of both coffee and maté herbal tea, and determined that there is "inadequate evidence" that either are a carcinogen. The Wall Street Journal first reported on the IARC findings Tuesday.
"it is the temperature, rather than the drinks themselves, that appears to be responsible."
But the IARC said there is evidence to suggest that drinks consumed at temperatures above 65°C (149°F) can cause cancer of the esophagus, classifying them as "probably carcinogenic to humans." The organization's findings were based on studies conducted in places like Iran, China, and South America, where tea is often consumed at around 70°C (158°F).
"These results suggest that drinking very hot beverages is one probable cause of esophageal cancer and that it is the temperature, rather than the drinks themselves, that appears to be responsible," IARC director Christopher Wild tells the AFP news agency.
June 15th, 11:35AM ET: Updated to include link to article in The Lancet Oncology.