Research has established a concerning link between consuming very hot beverages and an elevated risk of oesophageal cancer. According to a study involving nearly half a million adults in the United Kingdom, those who consumed eight or more cups of tea or coffee at temperatures exceeding 65°C were found to be almost six times more likely to develop this type of cancer compared to individuals who do not regularly consume hot drinks.
In 2016, the International Agency for Research on Cancer classified the consumption of beverages served at very high temperatures—specifically above 65°C—as “probably carcinogenic to humans.” This classification places it in the same risk category as long-term exposure to indoor wood smoke and excessive red meat consumption. The agency’s findings indicate that it is the temperature of the beverages, rather than their specific content, that poses the health risk.
Evidence from Global Studies
The association between hot drink consumption and oesophageal cancer has been extensively studied, particularly in regions such as South America. Traditional drinks like maté, typically consumed at around 70°C, have been linked to increased cancer risk. Similar findings have emerged from studies conducted in the Middle East, Africa, and Asia, reinforcing the global concern regarding very hot beverages.
Until recently, substantial research on this topic in European and Western populations was limited. The recent study conducted in the United Kingdom highlights the need for further examination in diverse demographic groups. It underscores the potential dangers of consuming hot beverages regularly, especially among those who prefer their drinks at higher temperatures.
Understanding the Mechanisms of Risk
The mechanism behind how hot drinks may contribute to cancer development involves cellular damage in the lining of the oesophagus. Researchers first proposed this theory nearly 90 years ago. Animal studies have shown that exposure to very hot water can lead to precancerous growths in the oesophagus. For instance, a 2016 study demonstrated that mice consuming water at 70°C developed these growths sooner than those given cooler water.
Another hypothesis suggests that heat damage to the oesophagus may weaken its protective barrier, increasing the risk of additional harm from gastric acid reflux. Over time, chronic damage to the oesophagus could elevate the likelihood of cancer development.
The volume and speed at which individuals consume hot beverages also appear to play a critical role in determining risk. Research indicates that large sips can cause significant temperature increases within the oesophagus, potentially leading to sustained heat injury. A study measuring oesophageal temperature found that a sip of 20 millilitres of coffee at 65°C could raise internal temperatures by up to 12°C.
While occasional small sips of hot drinks are unlikely to cause long-term harm, habitual consumption of very hot beverages may increase the risk of oesophageal cancer over time.
Recommendations for Safe Consumption
Given the brewing temperatures for coffee and tea often exceed safe limits, it is essential for consumers to be mindful of their drinking habits. For instance, takeaway beverages may be served at temperatures around 90°C to accommodate cooling during consumption.
Research from the United States has suggested an optimal temperature for coffee that balances flavour preservation with health considerations, identifying approximately 57.8°C as a safer drinking temperature.
To minimise risks, experts recommend taking time to enjoy hot drinks. Allowing beverages to cool for several minutes can significantly reduce their temperature—by as much as 10–15°C in just five minutes. Additionally, sipping slowly can help gauge the drink’s temperature and mitigate potential damage to the oesophagus.
Vincent Ho, an Associate Professor and Clinical Academic Gastroenterologist at Western Sydney University, emphasises the importance of being cautious when consuming hot beverages. As research continues to uncover the links between temperature and health risks, individuals are encouraged to rethink their drinking habits for long-term wellbeing.
