Many people enjoy hot beverages, from coffee and tea to various herbal infusions. Scientific inquiry has explored whether consuming these drinks at high temperatures poses a health concern, specifically regarding cancer risk. Understanding this science can help individuals make informed choices about their daily habits.
The Connection to Cancer
Scientific findings indicate a link between consuming very hot beverages and an increased risk of esophageal cancer. The International Agency for Research on Cancer (IARC), a part of the World Health Organization (WHO), classified drinking very hot beverages as “probably carcinogenic to humans” (Group 2A). This classification is based on epidemiological studies, particularly from regions where traditionally very hot tea or maté is consumed, such as parts of China, Iran, Turkey, and South America.
The proposed mechanism involves thermal injury to the cells lining the esophagus. Repeated exposure to very high temperatures can cause damage and scalding to the esophageal mucosa. This chronic thermal irritation may lead to inflammation, which over time, can increase the risk of developing esophageal squamous cell carcinoma (ESCC). Animal studies have also provided limited evidence supporting the carcinogenicity of very hot water.
Understanding Hot Temperatures
In the context of cancer risk, “hot” refers to specific temperature thresholds identified by research. The International Agency for Research on Cancer (IARC) has indicated that drinking beverages above 65°C (149°F) is considered potentially hazardous. Other research suggests that a temperature of 60°C (140°F) or higher could nearly double the risk of esophageal cancer for those who regularly consume such hot beverages.
These temperatures are often reached in commonly consumed hot beverages like tea and coffee, especially when served immediately after brewing. For instance, some takeaway outlets may serve coffee near boiling point, around 93°C (199°F). Beverages consumed at 70°C (158°F) are considered very hot and are associated with increased risk, as they can cause significant thermal injury to the esophagus.
Minimizing Potential Risks
Individuals can take practical steps to reduce any potential risk associated with hot beverage consumption. Allowing beverages to cool for a few minutes before drinking is a simple and effective strategy. Adding a dash of cold water or a splash of milk can also help lower the temperature to a safer range. If there is concern about specific temperatures, a food thermometer can be used to ensure the beverage is below the 65°C (149°F) threshold before consumption.
It is also important to consider that other factors significantly influence esophageal cancer risk. Smoking and alcohol consumption are major causes of esophageal cancer, particularly in many high-income countries. While hot beverage temperature is a factor, avoiding very hot drinks is one of several lifestyle adjustments that can contribute to reducing overall risk.