Research has revealed a concerning connection between the consumption of very hot beverages and an increased risk of oesophageal cancer. The International Agency for Research on Cancer classified drinks served above a temperature of 65°C as “probably carcinogenic to humans,” highlighting the potential health implications of enjoying tea, coffee, or other hot drinks at elevated temperatures.
Studies indicate that while there is no definitive evidence linking hot drinks to throat cancer and the relationship with stomach cancer remains unclear, the evidence regarding oesophageal cancer is more substantial. In a landmark report released in 2016, the Agency emphasized that it is the temperature of the beverage, rather than the drink itself, that poses the greatest risk. This conclusion was largely supported by research conducted in South America, where the traditional herbal drink maté, often consumed at around 70°C, has been associated with a higher incidence of oesophageal cancer.
The findings have been echoed by more recent studies, including a significant investigation conducted in the United Kingdom involving nearly half a million adults. This research confirmed that individuals who consume eight or more cups of very hot tea or coffee per day are almost six times more likely to develop oesophageal cancer compared to those who refrain from hot drinks.
The mechanism by which hot beverages may induce cancer involves damage to the oesophageal lining. Over time, regular consumption of very hot drinks can cause cellular damage, potentially leading to cancer. Research dating back nearly 90 years suggested this connection, although much of the early evidence stemmed from animal studies. In a 2016 experiment, mice predisposed to cancer were found to develop precancerous growths in the oesophagus more rapidly when exposed to water at 70°C compared to those given cooler water.
Additionally, the manner in which hot drinks are consumed can influence the level of risk. Larger sips can cause a more significant rise in temperature within the oesophagus. One study demonstrated that a sip of 65°C coffee could increase the oesophageal temperature by up to 12°C, leading to potential heat injuries over time. In contrast, occasional small sips are less likely to result in long-term damage.
Given the brewing temperatures for popular beverages often approach the boiling point of water, it is essential to consider safety when consuming hot drinks. Takeaway beverages frequently exceed 90°C, prompting concerns about the risk of heat injury. A study from the United States proposed an optimal serving temperature for coffee of 57.8°C, balancing flavour and the risk of heat-induced damage.
To mitigate the risk associated with hot drinks, experts recommend allowing beverages to cool before consumption. Research indicates that the temperature of a hot drink can decrease by 10–15°C within five minutes of being poured. Taking smaller sips can also help in assessing the temperature and reducing the likelihood of oesophageal damage.
According to Vincent Ho, Associate Professor and Clinical Academic Gastroenterologist at Western Sydney University, these findings reinforce the importance of being mindful about the temperature at which hot drinks are consumed. As the evidence mounts, individuals may want to reconsider the temperature of their preferred beverages to prioritize their long-term health.
