Very Hot Beverages Linked to Increased Esophageal Cancer Risk

Research indicates that the temperature of beverages such as tea and coffee may substantially impact health, specifically in relation to esophageal cancer. The International Agency for Research on Cancer (IARC) classified drinks served at temperatures above 65°C (149°F) as "probably carcinogenic to humans" in 2016. This classification was largely influenced by findings connecting very hot mate, a herbal tea popular in South America, with an elevated risk of esophageal cancer. Mate is often consumed at temperatures around 70°C (158°F). Previous evidence regarding the effects of hot beverages in Western populations had been inconclusive. Keren Papier, a nutritional epidemiologist from the University of Oxford, stated, "International research has shown for some time that drinking beverages like mate at very high temperatures is linked to increased risk of certain esophageal cancers." To investigate this further, Papier and her colleagues undertook an extensive analysis of data derived from two large UK studies – the Million Women Study and UK Biobank. The study involved 977,282 participants, marking it as one of the largest investigations into the correlation between hot drinks and esophageal cancer. Participants responded to queries regarding their hot drink preferences, categorising them as 'very hot', 'hot', or 'warm', and disclosed their daily consumption of tea and coffee. The findings suggested that individuals who preferred their drinks 'very hot' faced a relative risk increase of 3.17 times for developing esophageal squamous cell carcinoma (SCC) compared to those who consumed drinks designated as 'warm'. Those who indicated a preference for 'hot' drinks faced a 69% higher risk. Additionally, participants consuming six or more hot drinks daily experienced a 71% increased risk of SCC compared to those who consumed fewer than six, regardless of temperature preference. The researchers observed that this risk association was consistent whether the participants predominantly drank tea or coffee, and adding milk did not significantly modify the temperature-related risks. Although the study’s observational nature does not confirm a direct causation between hot drinks and cancer, the authors propose that reducing the temperature of beverages, even modestly, could mitigate the incidence of SCC. They estimated that if individuals who usually consumed very hot drinks switched to hot beverages, approximately 14% of esophageal SCC cases could be prevented, corresponding to about 440 cases annually in the UK. A notable limitation of the study is that it relied on participants’ self-reported drink temperatures rather than actual measurements. Future research will hopefully clarify this. While the biological mechanisms remain unexplored in this study, the evidence suggests that beverage temperature is a critical risk factor rather than the drink's composition itself. The authors referenced animal studies which demonstrated that exposure to very hot liquids (specifically at 70 °C) could induce lesions and tissue damage, while lower temperatures did not present the same risks. The findings appear in the International Journal of Cancer, providing insights into the relationship between beverage temperature and cancer risk, and may prompt lifestyle changes for many drinkers.