The Global Consensus on Hot Drinks
The conversation around hot beverages and health gained significant attention when the International Agency for Research on Cancer (IARC), a part of the World Health Organization (WHO), weighed in. After reviewing numerous studies, an international group
of scientists came to a noteworthy conclusion. They classified drinking “very hot” beverages as “probably carcinogenic to humans”. This was based on evidence from studies in regions where drinks like tea or maté are traditionally consumed at very high temperatures, around 70°C. These studies observed a connection between the temperature of the beverage and the risk of developing esophageal cancer.
It’s the Heat, Not the Drink
Crucially, the IARC’s findings point towards the temperature itself as the likely culprit, rather than the chemical composition of coffee or tea. In fact, the same review found no conclusive evidence that drinking coffee itself is carcinogenic and actually downgraded it to a category of 'not classifiable'. The focus shifted entirely to thermal injury. The concern is that regularly consuming liquids at scalding temperatures can cause repeated minor burns to the cells lining the esophagus. This process is known as chronic thermal injury. While your body is good at repairing this damage, constant injury and repair can, over a long period, lead to inflammation and increase the chances of cellular changes that might lead to cancer.
How Hot Is 'Too Hot'?
The critical question, then, is what temperature qualifies as “very hot.” The IARC and subsequent research define this threshold as any beverage above 65°C (149°F). To put this in perspective, coffee is often brewed at much higher temperatures, sometimes between 71-85°C, but it is typically consumed at a lower temperature. However, many people, particularly in cultures where drinking very hot tea is customary, consume it well within this risky range. One study in Iran, a region with a high incidence of esophageal cancer, found that people who drank 700ml of tea daily at 60°C or higher had a 90% increased risk compared to those who drank it cooler.
Recognising the Warning Signs
Acute thermal injury to the esophagus isn't always silent. Symptoms can include pain or difficulty when swallowing (odynophagia), chest pain, and a burning sensation. In some cases, endoscopy reveals visible damage to the esophageal lining, which can appear as whitish pseudomembranes or distinct red and white bands, sometimes called a "candy cane" appearance. While many of these acute injuries are reversible, they are a clear sign that the beverage was hot enough to cause tissue damage. Chronic, repeated exposure without such obvious symptoms is what poses the long-term risk.
Simple Steps for Safer Sipping
The good news is that reducing this potential risk doesn't require giving up your beloved chai or coffee. It simply calls for a small adjustment in habit. The most effective strategy is patience. Instead of drinking your beverage immediately after it's poured, allow it to cool for a few minutes. A good rule of thumb is to wait until it is comfortably warm, not scalding. Adding a small amount of cold milk or water can also quickly lower the temperature to a safer level. You don't need a thermometer; if you can't sip it comfortably without wincing or feeling a burn, it's likely too hot. Letting it cool to below 60°C is a safe target.
