A BBC health expert has responded to new research linking hot drinks such as tea and coffee to an increased risk of cancer. The study, funded by Cancer Research UK and published this week, found that people who said they enjoyed hot drinks had around a 1.7 times higher risk of cancer, while those who drank them very hot had around a three times higher risk compared to those who had drinks warm. Consuming six or more hot drinks per day also pushed up the risk compared to drinking fewer than six.
What the study found
Appearing on BBC Morning Live, Dr Oscar Duke explained the research focused on oesophageal cancer – cancer of the food pipe. He said: “It’s talking about oesophageal cancer risk. So, that’s cancer of the food pipe. Um, and one specific cancer of the food pipe which is important when we think about the numbers overall. So this is a study come from Oxford University looking at 977,000 individuals so you know nearly a million people to work out whether very hot drinks particularly those over 65 degrees which you know you might be if you’ve just boiled your kettle might increase the risk of cancer within that food pipe.”
The study, led by experts from Oxford Population Health at the University of Oxford, looked at data from around 980,000 adults by combining two large UK studies – UK Biobank and the Million Women Study. The two main types of oesophageal cancer are adenocarcinoma and squamous cell carcinoma (SCC). While drink temperature affected SCC risk in the study, there was no obvious impact on adenocarcinoma risk.
Dr Duke's verdict on the risk
Dr Duke said the theory is that hot temperatures cause damage to the cells lining the surface of the food pipe, which might then go on to form cancer. He said: “The thought being that potentially those hot temperatures cause damage to the cells lining the surface of the food pipe which then might go on to form cancer. Now they did find in people who are having very hot drinks a three times increase in one type of oesophageal cancer something called a squamous cell cancer of the oesophagus.”
He added: “Now it’s important when you look at any of these data you know three times you think that’s terrifying throwing your cups of tea away as we speak but hold on for a second.” He noted that squamous cell cancer, while potentially very serious, is not the most common type of oesophageal cancer. “Only about 30% of oesophageal cancers in the UK are this type of cancer anyway. So your lifetime risk of having that sort of cancer to your coffee aside is probably about 1% over your lifetime,” he said.
What experts recommend
Dr Duke concluded: “So whilst a three times increase might sound like a big figure potentially you’re increasing your risk to about 3% and that’s only if you’re having those very hot drinks also if you’re having more than six hot drinks that seem to be associated with increase in the study as well. So something to think about I suppose you know you don’t want to be burning your insides with your drink. Letting it cool down, popping some milk in there, having it more in a warm temperature than a hot or very hot temperature probably going to be helpful.”
He added: “But we don’t all need to give up tea and coffee. And there’s no signs from this that it’s the tea or the coffee itself that’s causing the damage. Just that temperature.”
Fiona Osgun, head of health information at Cancer Research UK, said: “While the risk of being diagnosed with this cancer remains relatively low in the UK, this research does add to the evidence that drinking very hot drinks could increase the risk of oesophageal squamous cell carcinoma.” She added: “There is however a simple step people can take – let a cuppa cool down a little before taking a sip.”
Dr Keren Papier, lead researcher and senior nutritional epidemiologist at Oxford Population Health, said: “International research has shown for some time that drinking beverages like mate at very high temperatures, as is typical in South America, is linked to increased risk of certain oesophageal cancers. What was less clear, was whether this also applied to the temperatures at which hot drinks are usually consumed in Western populations. This is now the largest study to look at that question in a UK population, where many people drink tea and coffee daily.”
The study did not record the temperature of drinks, but in 2016 the International Agency for Research on Cancer classified drinking very hot beverages (above 65C) as “probably carcinogenic”. The new study estimated the temperature at which coffee and tea is drunk in Western populations is around 60C. Overall, there are around 9,500 cases of oesophageal cancer in the UK every year, and people in the UK have around a 1% lifetime risk of being diagnosed with SCC.
