"we'd suggest just waiting until it's comfortable to drink"
A new UK study suggests that regularly drinking tea and coffee at very high temperatures could increase the risk of oesophageal cancer.
Researchers at the University of Oxford analysed data from 977,282 middle-aged men and women, making it the largest study to date examining the potential link between hot drinks and oesophageal cancer.
The study, published in the International Journal of Cancer, found that people who drank beverages classified as “very hot” had around three times the risk of developing oesophageal cancer compared with those who drank “warm” beverages.
However, experts stressed that the overall risk of developing the cancer remains low.
The researchers defined a “very hot” drink as one with a temperature of at least 65°C.
They believe that repeatedly consuming liquids at these temperatures could damage the cell lining of the oesophagus as they pass towards the stomach.
The findings also suggested that consuming six or more hot drinks each day was associated with a higher risk.
Adding milk to tea or coffee can reduce its temperature slightly, but researchers warned that milky drinks could still be too hot to drink safely.
A freshly brewed drink can remain considerably hotter than many people realise. Water reaches 100°C when fully boiled, while tea made immediately afterwards can still be around 90-95°C once poured into a cup.
Waiting a few minutes before drinking can therefore allow the beverage to cool to a more comfortable temperature.
Cancer Research UK said there is no exact recommended waiting time because the temperature of a drink will depend on factors such as how it is prepared and the type of cup used.
It added: “But if you’re worried, we’d suggest just waiting until it’s comfortable to drink rather than drinking it while it’s still very hot.”
Lead researcher Dr Keren Papier said previous research in South America had identified a similar association among people who regularly drink very hot mate, a traditional herbal beverage.
However, she said more evidence was needed to establish precisely which temperatures pose an increased risk.
The findings are particularly relevant because people may consider drinks that are comfortable to hold or taste as being at a safe temperature.
A separate study involving 118 young adults found that most participants considered black coffee too hot to drink when its temperature reached around 70°C or above.
Meanwhile, one takeaway coffee cup manufacturer recommends serving hot coffee at between 49°C and 60°C. Coffee requested “extra hot” can be served at temperatures above 82°C, according to MTPak Coffee.
The Oxford researchers estimated that around one or two in every 10 oesophageal cancer cases could potentially be prevented if people stopped drinking very hot beverages.
Squamous cell oesophageal cancer is rare, with a few thousand cases diagnosed in the UK each year. Around 1% of people in the UK are estimated to have a lifetime risk of developing this type of cancer.
This means that while drinking scalding hot beverages could increase an individual’s risk, their overall likelihood of developing oesophageal cancer remains relatively low.
There are also other established risk factors, with smoking and alcohol consumption posing greater risks for oesophageal cancer.
Fiona Osgun from Cancer Research UK, which funded the research, said:
“The most important ways to reduce the risk of this cancer type are not smoking and cutting down on alcohol.”
Symptoms of oesophageal cancer can include persistent heartburn or indigestion, pain in the throat or chest and unexplained weight loss.
People experiencing symptoms that are persistent, unusual or worsening should speak to a GP, particularly if they have concerns about their health.
