Very Hot Tea and Coffee May Raise the Risk of Oesophageal Cancer
Regularly consuming tea or coffee at extremely high temperatures may increase the risk of developing oesophageal cancer, according to a large UK study. Researchers from the University of Oxford examined health data from nearly one million middle-aged adults and found a possible link between the temperature of hot drinks and this rare form of cancer.
In particular, people who regularly drank beverages at 65°C or above were found to have about three times the risk of oesophageal cancer compared with those who preferred their drinks warm. However, experts stress that this does not mean that drinking a very hot beverage will necessarily cause cancer, as the overall likelihood of developing the disease remains low.
The researchers believe that repeated exposure to extreme heat could be part of the explanation. Very hot liquids may irritate or damage the inner lining of the oesophagus as they pass towards the stomach. Over time, repeated damage to these cells could contribute to changes associated with cancer.
The study also found that the quantity of hot drinks consumed may matter. People who reported drinking six or more hot beverages a day appeared to face a higher risk. Nevertheless, the researchers say more work is needed to establish exactly which temperatures and consumption patterns are most dangerous.
How hot is too hot?
For comparison, freshly boiled water reaches about 100°C, while tea or coffee poured into a cup may still be between 90°C and 95°C. Allowing the drink to stand for a few minutes can lower its temperature considerably.
There is no fixed amount of time that everyone needs to wait, according to Cancer Research UK. Instead, the charity advises people to wait until their drink feels comfortable before consuming it rather than drinking it while it is still extremely hot.
The concern is not limited to tea and coffee. Previous research in South America has also pointed to a similar relationship involving mate, a traditional herbal drink that is often consumed at very high temperatures. Dr Keren Papier, the study’s lead researcher, said further investigations are required to determine the exact temperatures associated with the increased risk.
Meanwhile, research involving 118 young adults who tasted different black coffees found that most participants considered the drinks too hot only when they reached around 70°C or more. By comparison, a manufacturer of takeaway coffee cups recommends a serving temperature of between 49°C and 60°C.
Overall risk remains low
Despite these findings, researchers emphasize that oesophageal cancer is uncommon. They estimate that roughly 10% to 20% of cases could potentially be prevented if people stopped consuming beverages at extremely high temperatures. However, the disease affects only a few thousand people each year, and the lifetime risk of developing squamous cell oesophageal cancer in the UK is around 1%.
More importantly, very hot drinks are not considered the main risk factor. Smoking and excessive alcohol consumption have a much stronger connection with oesophageal cancer.
Fiona Osgun of Cancer Research UK, which supported the research, therefore highlights avoiding tobacco and reducing alcohol consumption as the most effective ways of lowering the risk.
Finally, people should be aware of possible warning signs. Symptoms can include persistent heartburn, indigestion, discomfort or pain in the throat or chest, as well as unexplained weight loss. Although these symptoms can have many other causes, persistent or unusual changes should be discussed with a healthcare professional.
