Coffee lovers received mixed news recently on their favourite beverage, with the World Health Organisation essentially clearing coffee of causing cancer, while in the same breath warning that very hot drinks of any sort may increase your risk of oesophageal cancer.
It was a classic case of giving with one hand while making a fiery red STOP sign with the other.
Now Australia's leading expert on the environmental causes of cancer, Professor Bernard Stewart of the University of NSW, has weighed in on the issue, echoing the WHO's message while hinting at a way to have your coffee (hot) and drink it too.
THE PROBLEM WITH REQUESTING "EXTRA HOT"
Writing for the thecoversation.com.au and the latest Oncology Newsletter, Stewart says science became suspicious of very hot drinks decades ago when it observed that incidence of oesophageal cancer varied by as much as a hundred-fold between different communities in Iran. Research implicated beverage-temperature preferences in this disparity.
"Hot drinks damage tissue, particularly the lining of the oesophagus, the tube running from the throat to the stomach," Stewart says.
While scalding injury to body tissue is not known to cause cancer, experimental data suggest cancer may arise when that same compromised tissue comes in contact with a carcinogen, such as those found in certain foods.
YOUR PREVENTION PLAN
What foods? The answer is foods containing N-nitriso compounds – bacon, pepperoni and other smallgoods. Nicotine is riddled with the stuff, too.
"There are a number of examples where exposure to a carcinogen combined with chronic injury or inflammation have been determined to have caused cancer," Stewart explains. "Cases of stomach cancer have been attributed to the combination of N-nitriso compounds and a gastric infection."
One logical takeout is that if you're going to drink your tea and coffee hot, avoid consuming processed meats as part of the same meal or, better still, on the same day. But there is no clearcut data on this. It could be that low level, hot coffee-induced oesophageal inflammation lasts for days or more after that steaming long black.
In lieu of further research, your safest course is to follow clearcut official guidelines on smoking (don't do it!) and bacon-sandwich consumption (very sparingly), while letting your hot drinks cool a little before raising them to your lips.