Drinking Very Hot Tea and Coffee Triples Esophageal Cancer Risk, Oxford Study Finds
A major UK study of nearly 980,000 people reveals that drinking very hot tea or coffee nearly triples the risk of esophageal squamous cell carcinoma. Researchers advise letting hot beverages cool down.
A large-scale study conducted in the UK has found that people who prefer drinking their tea or coffee "very hot" face a nearly threefold higher risk of developing esophageal squamous cell carcinoma (SCC) compared to those who drink them lukewarm. Led by researchers at the University of Oxford, the study analyzed data from approximately 980,000 individuals, making it the largest of its kind conducted in the UK.
The researchers analyzed data from two major cohorts: the UK Biobank and the Million Women Study. Participants were asked to describe their preferred temperature for hot beverages as "very hot,hot," or "warm/lukewarm." These responses were then cross-referenced with their medical records over a follow-up period spanning more than a decade.
The results showed that individuals who preferred "hot" beverages had a roughly 70% higher risk of developing SCC compared to those who preferred them lukewarm. For those who drank them "very hot," the risk was approximately three times higher. Conversely, researchers found no clear association between beverage temperature and adenocarcinoma, the other main type of esophageal cancer.
"This is now the largest study to look at this question in a UK population, where many people drink tea and coffee every day," said Dr. Keren Papier, lead author and senior nutritional epidemiologist at Oxford Population Health. She noted that the findings add to existing evidence suggesting that drinking very hot beverages may increase the risk of esophageal squamous cell carcinoma. However, she emphasized that further research is needed to pinpoint the exact drinking temperatures associated with increased risk.
Temperature and Quantity Both Matter
Alongside temperature, the researchers also identified a link with the volume of beverages consumed. After accounting for drinking temperature, consuming six or more hot cups a day was associated with a 71% increase in SCC risk compared to consuming fewer than six cups. No similar significant association was found for adenocarcinoma.
This indicates that temperature is not the only critical factor, and quantity also plays a role. The findings suggest that both variables—how hot and how frequently drinks are consumed—may contribute to overall risk.
The proposed mechanism is relatively straightforward: extremely hot liquids can cause repeated thermal injury to the cells lining the esophagus. Researchers believe this chronic trauma may induce inflammation or compromise the tissue's natural barrier, making it more vulnerable to carcinogens. Nevertheless, this remains a proposed mechanism, and observational studies cannot definitively prove causation.
A Warning Issued Years Ago
The new findings align with a warning issued back in 2016 by the International Agency for Research on Cancer (IARC), the cancer research arm of the World Health Organization. The agency classified drinking beverages at temperatures above 65 degrees Celsius as "probably carcinogenic to humans" (Group 2A).
At the time, the IARC stressed that the suspicion surrounds heat rather than any specific beverage. Studies conducted in China, Iran, Turkey, and South America found that esophageal cancer risk rose as the consumption temperature increased. Mate, a popular infusion in South America, is sometimes consumed at around 70 degrees Celsius, though mate not consumed very hot was not classified as carcinogenic.
Despite the study's exceptional scale, researchers pointed out a notable limitation: they did not measure the temperature of every beverage consumed using a thermometer. Instead, participants self-reported their preferred drinking temperatures.
How Long Should You Wait?
The simple answer is that there is currently no universally agreed-upon number of minutes to wait. Contrary to claims that researchers recommend waiting precisely three to five minutes, Cancer Research UK, the charity that funded the study, notes it is difficult to establish an exact timeframe for when a drink becomes safe.
"If you are worried, we simply suggest waiting until it is comfortable to drink, rather than consuming it while it is still very hot," said Fiona Osgun, health information manager at the charity.
Experts also urge keeping the risks in perspective. An individual's lifetime risk of developing esophageal SCC in the UK is about 1%, meaning that even a significant relative risk increase does not make the disease common.
Smoking and alcohol consumption remain the primary and most established risk factors for this type of cancer. Therefore, Cancer Research UK emphasizes that the most important steps to reduce risk are to quit smoking and cut down on alcohol. Alongside these measures, letting a piping-hot cup of coffee or tea cool down until it is comfortable to drink remains a simple, prudent precaution.
