Hot coffee may raise oesophageal cancer risk: UAE doctors explain the 65°C threshold

Most of us have done it: taken that first impatient sip of coffee straight from the machine, then immediately regretted it as the heat hits the tongue and throat. Tea gets the same treatment, especially when we're in a hurry and don't want to wait for the cup to cool.

New research suggests that habit may carry more than a burned tongue's worth of consequences.

The study

A large study from Oxford University, published in the International Journal of Cancer, has found an association between drinking very hot tea or coffee and a higher risk of oesophageal cancer. Researchers followed nearly one million middle-aged adults in the UK and found that people who habitually drank their beverages 'very hot' had roughly three times the risk of oesophageal cancer compared with those who drank them at lower temperatures.

The finding echoes earlier research from populations where scalding drinks are part of daily life, including parts of South America, where hot mate is a traditional beverage.

But before you eye your morning coffee with suspicion: the research points to the heat, not the coffee itself, as the culprit.

How hot is too hot?

For the Oxford study, researchers used 65°C (149°F) as the threshold for a drink to count as 'very hot' — considerably hotter than what most people would call comfortable. Freshly boiled water can reach around 100°C, while tea poured shortly after boiling may still sit at 90–95°C. Freshly made coffee, depending on preparation, can easily run hotter than the 65°C mark too.

And our own sense of 'too hot' may not be a reliable guardrail. A separate, smaller study of 118 young adults found that participants generally didn't perceive a drink as "too hot" until it hit around 70°C, meaning a drink can be dangerously hot without feeling intolerable. The Oxford research, drawing on 977,282 participants, also found that greater consumption of very hot beverages tracked with greater risk.

Dr. Marwan Ibrahim, Specialist Family Medicine at Medcare Medical Centre, puts it plainly: "There is no single temperature at which a drink suddenly becomes harmful, but around 65°C is commonly used in research when referring to beverages as 'very hot," he says. " Freshly prepared tea or coffee can sometimes reach or exceed this temperature, particularly when consumed immediately.

In practical terms, if a drink feels too hot on the lips or throat, it is better to wait a few minutes and allow it to cool to a comfortable temperature.

Why temperature matters

Every time a very hot drink travels down the oesophagus, it exposes the delicate lining to that heat. Repeated exposure is where the trouble lies — over time, it can irritate and injure the tissue, and researchers are now examining closely how this ongoing cycle of injury might contribute to the cellular changes associated with cancer.

Dr. Jamila Khan, Specialist Gastroenterologist at Aster Cedars Hospital & Clinic, puts the long-term stakes plainly: "Over long time the repeated cycles of injury can cause inflammation and also increase risk of oesophageal squamous cell carcinoma."

She's also careful to point out that 65°C isn't a hard line beneath which a drink is guaranteed safe. Rather, it's the temperature at which the evidence linking hot beverages to a heightened risk of oesophageal cancer becomes strong enough to warrant concern, strong enough, in fact, that the International Agency for Research on Cancer (IARC) has classified very hot beverages as "probably carcinogenic to humans" (Group 2A).

The classification followed a review of epidemiological data drawn from regions where drinking very hot beverages is a deeply ingrained cultural habit.

What 'three times the risk' actually means

The phrase from the original Oxford study, sounds alarming, but it deserves context. A threefold increase describes relative risk, not absolute odds, it isn't a claim that someone who drinks very hot coffee has a three-in-three chance of developing oesophageal cancer

Dr. Ibrahim is careful on this point: The figure reflects relative risk, rather than meaning that a person has a threefold likelihood of developing the disease in absolute terms. "And the disease itself remains uncommon in many populations, which is part of why the underlying absolute risk still matters when weighing the finding.

That's not the only variable in play, either. Smoking, alcohol, age, diet, and general health all factor into a person's overall risk, Dr. Ibrahim notes, which is why he frames the study less as cause for alarm than as pointing to an avoidable risk factor, rather than something that should cause unnecessary fear.

Dr. Khan makes much the same case from the gastroenterology side: esophageal squamous cell carcinoma is relatively uncommon in many populations, as she says, and it's specifically the repeated, regular intake of hot drinks, not an occasional hot cup, that raises the risk. As she notes, this is a modifiable long term risk," she says, not a reason to avoid tea altogether.

Is coffee the problem?

For coffee and tea drinkers, this is probably the question that matters most — and the answer, from both doctors, is no.

Dr. Ibrahim locates the concern squarely in temperature rather than the drink itself: tea and coffee, he says. It can be enjoyed as part of a balanced lifestyle, with the problem arising only when they're routinely consumed hot enough to repeatedly irritate the oesophagus.

Does frequency make a difference?

There's a significant gap between one overly hot sip on a rushed morning and a daily habit of drinking everything scalding, and both doctors see frequency as central to the risk.

Dr. Ibrahim's logic is straightforward: repeated exposure means repeated irritation, so an occasional too-hot drink isn't comparable to several scalding ones every day. His suggested fix is almost anticlimactic in its simplicity, not cutting out tea or coffee, but letting very hot drinks cool for a few minutes first, a habit he calls a simple way to cut down on repeated thermal exposure.

Furthermore, the requent intake means more frequent thermal injury, which may accelerate the process of inflammation, scarring, and carcinogenesis. The difference between an occasional hot drink and several a day, Dr Khan stresses, isn't trivial, it's the difference between rare exposure and cells repeatedly absorbing thermal injury, with each cycle nudging the process of inflammation and carcinogenesis along a little further.

So, should you stop drinking hot coffee?

Not necessarily. Nothing here suggests coffee needs to disappear from your morning routine, just that there's one more reason to resist gulping it down the moment it's poured.

Letting your coffee or tea sit for a few minutes before drinking is a small, almost forgettable adjustment. But it cuts down repeated exposure to the kind of heat your oesophagus was never built to shrug off.

And if that first sip makes you wince? Take it as your cue to wait.