Hot tea and coffee may increase the risk of oesophageal cancer, Oxford study finds

A study conducted by researchers at the University of Oxford has raised concerns about a possible risk associated with drinking very hot tea or coffee: people who regularly consume such beverages at very high temperatures may face a significantly greater risk of oesophageal cancer. The research, cited by the BBC, drew on data from 977,282 middle-aged men and women and is described as the largest analysis of its kind carried out to date.

The findings, published in the International Journal of Cancer, show that people who drink their beverages "very hot" had approximately three times the risk of developing oesophageal cancer compared with those who consume hot drinks but not at extreme temperatures. The study defines "very hot" as any beverage at a temperature of at least 65 degrees Celsius. The risk was also higher among people who drink six or more hot beverages per day.

Why temperature matters

Very hot liquid can damage the cells lining the oesophagus as it travels towards the stomach. Adding milk can lower the temperature, but the drink may still remain too hot. For context: freshly boiled water reaches approximately 100 degrees Celsius, whilst tea or coffee poured immediately into a cup can be between 90 and 95 degrees.

Another study, conducted on 118 young adults who repeatedly tasted black coffee at various temperatures, found that most considered the drink too hot at around 70 degrees Celsius. For takeaway coffee, one cup manufacturer recommends an ideal serving temperature of between 49 and 60 degrees, though an "extra hot" order may be served at above 82 degrees.

Expert recommendations

Experts suggest allowing hot drinks to cool for a few minutes before consuming them. Cancer Research UK notes that there is no precise recommended time frame, but that people should wait until the drink can be consumed comfortably without it being very hot.

Dr Keren Papier, who led the study, explained that earlier research in South America — where maté, a traditional herbal drink, is frequently consumed at very high temperatures — had shown a similar link with oesophageal cancer. However, she stressed that further studies are needed to establish more precisely the temperatures associated with increased risk.

Overall risk remains low

According to the researchers, approximately one or two in ten cases of oesophageal cancer could potentially be prevented if people stopped drinking very hot beverages. Squamous cell oesophageal cancer is nonetheless a rare form of the disease, affecting several thousand people each year. In the United Kingdom, the lifetime risk of being diagnosed with this form of cancer is approximately 1%.

Specialists emphasise that smoking and alcohol consumption remain more significant risk factors for oesophageal cancer. Fiona Osgun, a spokesperson for Cancer Research UK, noted that quitting smoking and reducing alcohol intake are the most effective preventive measures. Possible symptoms of oesophageal cancer include heartburn, indigestion, pain in the throat or chest, and weight loss.