A UK study suggests that regularly drinking very hot beverages like tea and coffee may increase the risk of oesophageal cancer, though the overall chances of developing the disease remain low. The research, published in the International Journal of Cancer, analyzed data from nearly a million people and found that those who consumed drinks at 65 degrees Celsius or above had around three times the risk of developing the cancer compared to those who drank warmer beverages. The study, led by Oxford University, defines 'very hot' as any drink at or above 65 degrees Celsius, which can damage the cell lining of the oesophagus as it travels to the stomach.

The findings are based on data from 977,282 middle-aged men and women, with the researchers noting that consuming six or more hot drinks per day also raises the risk. While adding milk can slightly cool the drink, a milky tea or coffee may still be too hot, according to the study. Tea made immediately after boiling a kettle can reach temperatures of 100 degrees Celsius, which drops to around 90 or 95 degrees Celsius once poured into a cup. The researchers recommend waiting a few minutes before drinking to allow the beverage to cool to a safer temperature.

Cancer Research UK, which funded the study, acknowledges that it is difficult to determine an exact cooling time for hot drinks. However, the charity advises waiting until the drink is comfortable to drink rather than consuming it while it is still very hot. Dr. Keren Papier, the lead researcher, noted that similar links between hot drinks and oesophageal cancer have been observed in South America, where people often consume very hot herbal beverages like mate. She emphasized the need for further research to pinpoint the exact temperatures that pose the greatest risk.

The study also highlights that while scalding hot drinks may increase someone's risk, the overall likelihood of developing oesophageal cancer remains low. The researchers estimate that around one or two in every 10 cases of oesophageal cancer could be avoided if people stopped drinking very hot beverages. However, other factors such as smoking are considered greater risk factors for the disease. Fiona Osgun from Cancer Research UK stressed that the most important ways to reduce the risk of oesophageal cancer are not smoking and limiting alcohol consumption.

The study does not provide a definitive answer on the exact temperature at which hot drinks become dangerous, with some research suggesting that most people find drinks too hot only when they reach 70 degrees Celsius or above. A coffee cup manufacturer, MTPak Coffee, states that the ideal temperature for hot coffee on the go is between 49 and 60 degrees Celsius, but that it can be served at over 82 degrees Celsius if a customer requests it to stay hotter for longer. The study also notes that symptoms of oesophageal cancer can include heartburn, indigestion, a pain in the throat or chest, and weight loss, though these are not specific to the condition.

What remains unknown is the precise temperature threshold that significantly increases cancer risk, as well as the long-term effects of regular consumption of very hot drinks. Further research is needed to clarify these details and to determine the most effective ways to mitigate the potential risks associated with hot beverages.