A major research study has identified a significant link between the temperature of hot beverages and an increased risk of developing cancer of the gullet. According to findings published on Wednesday in the International Journal of Cancer, individuals who consume tea and coffee at a "very hot" temperature face a threefold higher risk of developing oesophageal squamous cell carcinoma (SCC) compared to those who prefer warmer drinks.
The study, which is described as the world’s largest of its kind, was led by Dr. Keren Papier, a senior nutritional epidemiologist at the University of Oxford’s population health department. Researchers observed that the risk of SCC increased not only with higher temperatures but also with the frequency of consumption. After adjusting for how often people drank hot beverages, those who consumed six or more hot drinks daily faced a 71% increase in SCC risk compared to those who drank fewer than six.
Interestingly, the study noted that while high temperatures are linked to SCC, they do not appear to increase the risk of developing adenocarcinoma (AC), the other primary form of oesophageal cancer. The researchers relied on self-reported preferences, asking participants to categorize their drinks as "very hot," "hot," "warm," or to indicate that they do not consume hot drinks. Rather than using measured temperatures, the findings are based on these subjective estimations.
Medical experts suggest that the heightened risk is likely due to heat-related damage to the cells lining the oesophagus. The International Agency for Research on Cancer, a division of the World Health Organization, had previously classified hot drinks as "probably carcinogenic to humans" in 2016. In the UK, it is estimated that one in seven cases of SCC could potentially be avoided if individuals who currently drink their beverages at a "very hot" temperature chose to consume them at a more moderate "hot" temperature instead.
Fiona Osgun, head of health information at Cancer Research UK—which funded the research—advised that while it is difficult to specify an exact cooling time, people should wait until their drink is at a comfortable temperature before consuming it. However, the charity does not advocate for cafes and restaurants to lower their serving temperatures.
Some experts have expressed caution regarding the study's methodology. Muy-Teck Teh, a professor of molecular oral oncology at Queen Mary University of London, pointed out that the reliance on self-reported temperature data is a limitation. He noted that perceived temperature is subjective and questioned whether those who prefer very hot drinks might possess an underlying biological predisposition or altered sensitivity that complicates the interpretation of direct causality.
