How you take your tea is an oft-divisive, deal-breaking topic. Do you like a classic builder’s with enough sugar to stand a spoon up in or a mug of warm milk that has just been kissed by a tea bag. Milk or tea first? Tea bag or loose leaf? There’s even a correct way to make the best tea according to science (and nope, even we’re not on board with it).
But there is something that we should all be able to agree on. Consuming burning-hot liquid is really not good for you.
According to a new study in Annals of Internal Medicine, slurping scalding tea can increase your chances of esophageal cancer, especially when combined with being a regular smoker and alcohol drinker.
This isn’t the first time drinking very hot tea has been associated with esophageal cancer. In an accompanying editorial, the authors of the study quote the 1930's New York physician WL Watson: “The drinking of copious amount[s] of excessively hot tea is a history frequently obtained from Russian-born patients coming to Memorial Hospital suffering from cancer of the esophagus.”
However, drinking very hot beverages is still considered a “probable” rather than definite carcinogen according to the most recent evaluation by the International Agency for Research on Cancer, back in 2016.
In this new study, researchers in China found that those who drank scalding hot tea – as well as smoking tobacco and regularly consuming alcohol – were five times more at risk of developing esophageal cancer than those without any of the three habits.
Over 456,000 participants between the ages of 30 and 79 took part in the study, at the start of which they had to fill out a questionnaire on their tea-making and drinking habits, including what temperature they drank it – room temperature, warm, hot, or burning hot.
Now, before you get too worried, the researchers readily admit that scalding tea doesn’t seem to affect those who are not smokers or drinkers; there was no increased risk of esophageal cancer observed.
However, for those who did smoke and drink, the increase was fivefold. So how hot is too hot?
The esophagus is the muscular tube that connects the throat to the stomach. There are two types of esophageal cancer; adenocarcinomas, where the cancer starts in the gland cells that make mucus, and squamous cell carcinoma, starting in the squamous cells that line the esophagus, which is the most common.
The researchers found that drinking very hot tea – prepared and drunk at around 65°C (149°F), which is much hotter than your average cup – can damage the cells lining the esophagus, increasing the risk of squamous cell carcinoma.
So, the next time you are preparing a brew, no matter how much you need a cuppa, perhaps wait a few moments for it to cool down before taking a slurp.