PARIS • Drinking very hot coffee and other liquids "probably" causes cancer of the oesophagus, a UN agency said yesterday, but lifted suspicion from a cup of joe at "normal serving temperatures".
For some types of cancer, there were hints that coffee may even be beneficial, said the International Agency for Research on Cancer (IARC) - but not if consumed hotter than 65 deg C.
A review of over 1,000 studies concluded that drinking "very hot" beverages was "probably carcinogenic to humans", said the agency.
"It doesn't matter what the liquid is. What matters is the temperature," said Dr Dana Loomis, who took part in the review of the world's most popular hot drinks.
The IARC looked at the full complement of published scientific literature considering if there was a cancer link to coffee or mate, a South American herbal infusion that is also popular in the Middle East.
Only when drunk hotter than 65 deg C did any association arise with cancer of the gullet - the pipe that transports food and fluids from the throat to the stomach.
Both have been classified as "possibly cancerogenic to humans" since 1991, when the last evaluation was done. But studies since could link neither drink to a higher cancer risk, said the IARC, an agency of the World Health Organisation.
Only when drunk hotter than 65 deg C did any association arise with cancer of the gullet - the pipe that transports food and fluids from the throat to the stomach, it added.
But there is some good news for coffee drinkers. The analysis found that at "normal" temperatures, there was some data pointing to a lower risk of cancer of the uterus, liver and breast.
Studies have also found that coffee has strong antioxidant effects and other possible health benefits.
Taken together, the available data suggests "there is inadequate evidence in humans for the carcinogenicity of coffee drinking".
It also scoured studies on the possible link between cancer and other hot beverages, including milky teas drunk in parts of Africa and Central Asia. Some of the data pointed to "significantly increased relative risks for drinking very hot tea and very hot beverages".
And in laboratory studies, very hot water at 65-70 deg C boosted oesophageal tumours in mice and rats, said the agency.
But the IARC - partly due to a lack of research - did not find that drinking very hot water was similarly dangerous.