Rachel Thompson is Head of Research Interpretation at World Cancer Research Fund International.
You may have already heard about the new research from the International Agency for Research on Cancer, which shows that drinking hot drinks over 65 degrees Celsius can increase the risk of oesophageal cancer. These findings are very interesting, and trigger some important considerations around what we should or shouldn’t drink to help prevent cancer.
What do we already know about hot drinks and cancer?
Our own research analysis has found evidence for increased risk of oesophageal cancer from people drinking the South American herbal tea, maté, scalding hot through a metal straw.
It is therefore not surprising that this is seen to be reflected in other beverages that are drunk at very high temperatures. We will be carrying out further research analysis into hot beverages in the future, including evaluating the possible mechanisms of how a scalding drink could increase cancer risk.
It’s the temperature that counts
Both the temperature and the amount of maté that people drank were analysed and the results showed that the risk of cancer increased with temperature, independent of the amount of maté that was consumed. There were statistically significant increases in risk for drinking very hot maté, but not for drinking warm or cold maté.
What about coffee?
Back in 1991, the last time IARC looked at hot drinks and cancer risk, it was thought that coffee could possibly increase cancer risk. Since then, IARC have reevaluated the evidence and concluded that coffee is not carcinogenic.
This doesn’t surprise us; in fact our own research found a link between drinking coffee and a reduced risk of liver and womb cancer. However, more research is required before providing a recommendation on drinking coffee, such as how much coffee you would have to drink to reduce your risk, what type of coffee you would need to drink and what the effect is of adding milk.
So, if you’re not already a coffee drinker, we don’t yet have enough evidence to tell you to take up the habit - there are some questions we need to answer first.
Though coffee itself may not be carcinogenic, the problem with drinking very hot liquids still exists. If the drink is hotter than 65 degrees Celsius, it could increase your oesophageal cancer risk. This is more of an issue in countries which are accustomed to enjoying drinks at very hot temperatures, such as those in the Middle East where it is the norm to enjoy beverages straight from the boil.
What does this mean for tea and coffee lovers?
To all the tea and coffee lovers out there, these new findings don’t mean that you can no longer enjoy hot drinks. It is the very hot temperatures that have been identified as a cancer risk and so, when drinking tea, coffee or other hot drinks, just let it cool down for a few minutes before taking a sip.