Drinking hot tea and coffee TRIPLES risk of developing cancer, study reveals

Published today in the International Journal of Cancer, the research was spearheaded by Dr Keren Papier, a senior nutritional epidemiologist at the University of Oxford's population health department.

The study also received funding from Cancer Research UK.

The investigation monitored close to 980,000 UK participants across a 14-year period, making it the biggest global study to examine the relationship between hot drink consumption and gullet cancer.

Crucially, the elevated risk applied only to squamous cell carcinoma (SCC), not to adenocarcinoma (AC) – the other main type of oesophageal cancer.

Participants were asked to describe their preferred drinking temperature, choosing from categories including "very hot", "hot", "warm" or no hot beverages at all.

The study's conclusions rested on individuals' own perceptions of temperature rather than precise measurements.

Drinking hot tea and coffee triples risk of developing cancer, study reveals

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"After controlling for drink temperature, daily consumption of six or more versus fewer than six hot drinks was associated with a 71% increase in SCC risk, with little association with AC risk," the researchers said.

This finding underscores how the heat of the beverage and the sheer volume consumed play distinct roles in elevating cancer risk.

The research team tracked the drinking habits and health outcomes of the participants over the full 14-year follow-up period.

These findings echo results from earlier research carried out across Asia, Africa, South America and the Middle East.

The study received funding from Cancer Research UK

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The study found consuming tea or maté — a caffeinated herbal drink widely favoured in South America — at temperatures of 70C or higher raised the likelihood of developing oesophageal cancer.

In 2016, the International Agency for Research on Cancer, the World Health Organisation's cancer arm, classified hot beverages as "probably carcinogenic to humans" and identified them as "one probable cause of oesophageal cancer".

The suspected mechanism involves thermal damage to the cells lining the oesophagus, commonly referred to as the foodpipe.

Repeated exposure to extreme heat is believed to injure these cells in ways that can trigger cancerous changes.

Alcohol consumption and smoking remain additional major risk factors for this form of the disease.

The study team estimated one in seven SCC cases in the UK could be prevented if people who reported drinking their beverages at "very hot" temperatures switched to consuming them at what would be classified as merely "hot".

Researchers argued public health authorities should use these results to promote cooler drink consumption and reduced intake of very hot beverages as a strategy for lowering SCC diagnoses.

The study team added: "This large UK study of middle-aged adults, amongst whom hot drinks are widely consumed, provides clear evidence that temperature and frequency of hot drink consumption represent useful targets for SCC prevention."

Fiona Osgun, head of health information at Cancer Research UK, said: "It's difficult to put an exact time on how long a hot drink should be left to cool.

"But if you're worried, we'd suggest just waiting until it's comfortable to drink rather than drinking it while it's still very hot."

Despite the study's significant scale, some experts have raised concerns about its methodology.

Professor Muy-Teck Teh, a specialist in molecular oral oncology at Queen Mary University, questioned the reliance on subjective temperature assessments.

"A key limitation, however, is that perceived drink temperature is inherently subjective, and it remains unclear whether individuals who tolerate or prefer very hot drinks have altered thermosensation or mucosal sensitivity that might itself reflect underlying biological predisposition to squamous cell carcinoma and lead them to prefer hotter drinks," he said.

"This possibility cannot be excluded and complicates interpretation of causality."

Cancer Research UK stopped short of recommending cafés, coffee shops and restaurants begin serving tea and coffee at lower temperatures as a preventive measure.