A new study published on Wednesday claims that those who drink tea piping hot could be increasing their risk of esophageal cancer, CNN reported.
The study, published in the International Journal of Cancer, found that those who preferred their tea to be warmer than 60°C and consumed more than 700 ml of tea per day — about two large cups — had a 90% higher risk of esophageal cancer, when compared to those who drank less tea and at cooler temperatures.
Researchers followed more than 50,000 people in Golestan, a province in northeastern Iran, aged between 40 and 75, for an average of 10 years. Between 2004 and 2017, the researchers detected 317 new cases of esophageal cancer.
"Many people enjoy drinking tea, coffee, or other hot beverages. However, according to our report, drinking very hot tea can increase the risk of esophageal cancer, and it is therefore advisable to wait until hot beverages cool down before drinking," said Dr Farhad Islami, of the American Cancer Society and the study's lead author.
Previous research has found a link between hot tea drinking and esophageal cancer, however, according to the authors this study was the first to pinpoint a specific temperature.
Esophageal cancer is the eighth most common cancer in the world and is often fatal. It is usually caused by repeated injury to the esophagus due to smoke, alcohol, acid reflux and — maybe — hot liquids.
The study said more research was needed on why exactly drinking very hot tea is associated with the higher risk of esophageal cancer.
Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, said that it was the heat that was the issue rather than the type of beverage. "In fact, it is probably anything hot: Microwaved jam has been known to cause esophageal injury. It is possible that the trauma leads to cell changes and hence to cancer," he Evans, who was not involved in the study, told the Science Media Centre.
Dr. James Doidge, senior research associate at University College London, said that hot drinks were an established risk factor for esophageal cancer. "It doesn't take a scientist to appreciate that repeated irritation of any body surface increases your risk of cancer. Sunburn gives us skin cancer, smoking gives us lung cancer, and many foods and drinks contribute to risk of gastrointestinal cancers," Doidge, who wasn't involved in the research, told the Science Media Centre.