A growing body of research is drawing attention to the temperature of coffee and other hot beverages, with scientists investigating whether regularly consuming drinks at extremely high temperatures could increase the risk of oesophageal cancer. The findings do not suggest that coffee itself causes cancer; instead, researchers are examining whether repeated exposure to very hot liquids may damage the oesophagus over time.
Recent UK research has added to the evidence surrounding the potential connection. Researchers found that people who preferred their drinks very hot appeared to have a substantially higher risk of developing oesophageal squamous cell carcinoma than those who preferred beverages at warmer temperatures. Participants who described their drinks as “hot” had nearly twice the risk, while those who preferred them “very hot” had around three times the risk compared with people who drank them warm.
However, the research has important limitations. Participants reported how hot they liked their beverages rather than having the precise temperature of every drink measured. As a result, scientists cannot establish an exact temperature at which the risk begins to rise. The findings also show an association rather than proving that consuming hot beverages directly causes cancer.
The possible explanation is linked to repeated thermal damage. Extremely hot liquids can burn or irritate the lining of the mouth and oesophagus. If such exposure occurs regularly, repeated injury and subsequent tissue repair could potentially contribute to cellular changes. Researchers are continuing to investigate how this process might contribute to the development of oesophageal cancer.
The issue has been examined internationally for years. In 2016, the International Agency for Research on Cancer, an organisation associated with the World Health Organization, classified drinking very hot beverages above 65°C as “probably carcinogenic to humans.” The classification was based on evidence connecting consumption of very hot beverages with oesophageal cancer.
Importantly, that assessment did not identify coffee itself as the problem. IARC found no conclusive evidence that coffee consumption causes cancer. The concern instead focused on beverages consumed at extremely high temperatures.
Other studies have also explored the relationship between thermal exposure and oesophageal squamous cell carcinoma. Research in parts of Africa examined factors such as beverage temperature, the speed at which drinks were consumed and whether people experienced burning sensations while eating or drinking. The findings provided additional support for the possibility that repeated heat exposure could play a role.
Oesophageal cancer has many potential risk factors, and hot beverages are only one area being investigated. Tobacco and alcohol consumption are established risk factors for oesophageal squamous cell carcinoma, while other lifestyle and medical factors can also influence an individual’s chances of developing the disease.
For coffee and tea drinkers, the findings therefore do not necessarily mean giving up their favourite beverages. A more straightforward precaution may be to allow drinks to cool for a short period before consuming them. Drinks that are hot enough to burn the mouth or throat are best avoided.
The research is particularly relevant because coffee and tea are everyday beverages for millions of people around the world. Because they are consumed so frequently, even a relatively modest risk associated with repeated exposure to extreme heat could be important at a population level.
Scientists are continuing to examine whether the temperature of drinks, frequency of consumption and length of exposure influence cancer risk. More research will be needed to determine the precise relationship and identify whether particular drinking habits carry greater risks.
For now, the evidence suggests that the temperature of a drink may matter more than whether it is coffee or tea. Allowing beverages to cool before drinking them is a simple precaution that can reduce exposure to extreme heat.
People should also pay attention to persistent symptoms that could indicate an underlying oesophageal problem. Difficulty swallowing, unexplained weight loss, persistent indigestion or other unusual symptoms should be discussed with a healthcare professional. Such symptoms can have many causes, but obtaining medical advice is important when they persist.