How do you like your tea? No, we’re not asking how much milk you take, but rather, how hot you like to drink it.
A new study from the University of Oxford suggests that people who reported drinking ‘very hot’ or ‘hot’ beverages may have a higher risk of developing a type of oesophageal cancer known as oesophageal squamous cell carcinoma (SCC).
If this news sounds familiar to you, that’s because scientists outside of the UK have been studying this association for years.
“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,” explains Dr Keren Papier, lead researcher and senior nutritional epidemiologist at Oxford Population Health.
“What was less clear, was whether this also applied to the temperatures at which hot drinks are usually consumed in Western populations.”
Now, with funding from Cancer Research UK, Papier and her team have analysed data from almost one million UK adults to uncover possible signs of a similar link here.
But, before you start worrying about your morning cuppa, it’s important to put the team’s findings into context. Oesophageal SCC is relatively uncommon in the UK, with people having around a 1% lifetime risk of being diagnosed, so even if someone’s risk increases it will still be quite low overall.
More research is still needed to understand exactly how drink temperature may affect our risk of developing oesophageal SCC. In this article, we’ll explore what the evidence tells us so far.
How hot do you like your tea?
For this study, Papier’s team analysed data from around 980,000 UK adults through the UK Biobank and the Million Women Study.
If they consumed hot drinks, participants were asked to report whether they typically drank them ‘very hot’, ‘hot’, or ‘warm.’ The researchers then tracked participants’ health records for over 10 years to see whether they developed oesophageal SCC.
Compared to people who reported drinking their beverages “warm”, the researchers found that those who preferred their drinks “hot” had nearly a two times higher risk of oesophageal SCC, and those who drank them “very hot” had a three times higher risk.
“This is now the largest study to look at that question in a UK population, where many people drink tea and coffee daily,” says Papier.
“It adds to existing evidence that drinking very hot drinks could increase the risk of oesophageal squamous cell carcinoma.”
It’s important to note that the study did not find that consuming tea and coffee increased the risk of oesophageal SCC – the risk was associated with the temperature of any hot beverage that was consumed.
What do we still need to find out?
While this new research adds to our knowledge around hot drinks and oesophageal SCC risk, the researchers were unable to measure actual drink temperatures given the large number of participants and duration of the study.
Based on research outside of the UK, the International Agency for Research on Cancer (IARC) classifies drinking very hot beverages (above 65C) as ‘probably carcinogenic’ to people. This temperature, however, is likely to be hotter than people’s usual cup of tea or coffee in the UK, so further research is needed to find out exactly what temperature could increase the risk of oesophageal SCC.
It’s also unclear how higher drink temperatures may be impacting oesophageal cancer risk; but so far, evidence suggests that they may damage the lining of the oesophagus, which, over time, can increase the chance of cancer.
Cancer Grand Challenges team PROMINENT, which is funded by Cancer Research UK, is taking a closer look at how this might happen. You can find out more about the team’s work on the Cancer Grand Challenges website.
Reducing your risk of SCC
A person’s risk of oesophageal cancer can depend on many factors. While the results of this study show a potential increase in risk of oesophageal SCC, if the initial risk is very small, the increase may not make much difference overall.
Here in the UK, there is a 1% lifetime risk of being diagnosed with oesophageal SCC. So even if very hot drinks might increase someone’s risk of oesophageal SCC, the chances of them developing the cancer are still quite low, because it isn’t very common.
While the evidence linking hot drinks to cancer risk is still evolving, there are proven ways you can reduce your risk of oesophageal SCC.
“The most important ways to reduce the risk of this cancer type are not smoking and cutting down on alcohol,” says Fiona Osgun, head of health information at Cancer Research UK.
But if you’re still worried, it might be good to let your tea or coffee cool down just a bit before taking a sip.
