For millions in India, a steaming cup of chai or coffee is a daily ritual. But could this comforting habit pose a hidden health risk? Emerging scientific evidence suggests the danger lies not in the drink itself, but in its temperature. Consuming beverages that are very hot, typically above 65 degrees Celsius (149°F), has been linked to an increased risk of oesophageal cancer, also known as cancer of the gullet.
The Official Verdict from Global Cancer Experts
In a significant review in 2016, the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), examined all available evidence. The agency concluded that drinking very hot beverages is 'probably carcinogenic to humans'. This classification, known as Group 2A, specifically points to the damage caused by high temperature, not to tea, coffee, or mate as chemical substances.
The IARC's focus is squarely on the thermal injury caused to the lining of the oesophagus when it is repeatedly scalded by liquids at high temperatures.
How Can Temperature Lead to Cancer?
The biological mechanism is a clear sequence of damage and repair gone wrong. When you sip a very hot drink, it can scald the sensitive cells lining your food pipe. If this happens frequently—multiple times a day over years—it leads to chronic inflammation and increased cell turnover as the body tries to heal itself.
This constant state of repair, with cells dividing more often, raises the probability of errors in DNA replication. Over many years, these accumulated errors can pave the way for cancer development. This pathway is supported by both animal experiments and human observational studies.
What Do the Scientific Studies Show?
Multiple large-scale studies and meta-analyses have consistently found an association between drinking very hot beverages and a specific type of throat cancer: oesophageal squamous cell carcinoma (ESCC). This link is particularly strong in populations where consuming piping hot tea or mate is a cultural norm.
More recent, robust research—including analyses from the UK Biobank—has strengthened this case by objectively measuring cup temperature, moving beyond reliance on personal memory, which can be biased. These prospective studies confirm that habitual consumption of very hot drinks is tied to a higher future risk of ESCC.
However, it's crucial to understand the nuance. The association is primarily with ESCC and the temperature and frequency of consumption. Links to other cancers remain weak or unproven. Furthermore, in many high-risk regions, other strong factors like tobacco use, heavy alcohol consumption, and certain dietary compounds are also prevalent, which can amplify risk or complicate research findings.
Practical Tips for Safe Sipping
You don't need to give up your beloved chai or coffee. A few simple habit changes can significantly reduce any potential risk:
Let it cool: The simplest step is to wait. A pause of 3 to 5 minutes after pouring from a kettle or heater can bring the temperature below the 65°C danger zone.
Know your temperature: Use a kitchen thermometer once to gauge how hot your typical drink is. This awareness can guide your cooling time.
Sip, don't gulp: Taking smaller sips allows the liquid to cool slightly in your mouth and reduces the thermal shock to your oesophagus.
Focus on major risks: Remember that tobacco and alcohol are far more potent risk factors for oesophageal cancer than drink temperature. Managing these provides a greater health benefit.
The key takeaway from recent science is that the risk is tied to frequent, long-term exposure to very hot liquids, not the occasional warm cup. For individuals with a history of oesophageal issues, extra caution is advisable.
Disclaimer: This article summarizes published scientific evidence for informational purposes. It is not a substitute for professional medical advice. Individuals with specific health concerns should consult a healthcare provider for personalised guidance.
