Drinking very hot tea or coffee may raise risk of throat cancer, Study

People who often drink their tea or coffee very hot may have a much higher chance of getting oesophageal cancer, a study shows.

The researchers discovered that those who liked their drinks very hot had over three times the risk of developing oesophageal squamous cell carcinoma (SCC) compared to those who preferred warm drinks.

This study looked at nearly 980,000 middle-aged adults in the United Kingdom and was published in the International Journal of Cancer.

Oesophageal cancer affects the tube that carries food and drinks from the mouth to the stomach. Oesophageal SCC is the most common type of this cancer worldwide.

What temperature is too hot?

The International Agency for Research on Cancer (IARC), which is part of the World Health Organisation (WHO), says drinks that are hotter than 65°C might be “probably carcinogenic to humans.”

For this new study, researchers used data from participants in the UK Biobank and Million Women Study.

Participants reported how hot they usually liked their tea, coffee, and other hot drinks, choosing from “very hot,” “hot,” and “warm.” They also shared if they drank fewer than six or at least six hot drinks each day.

During the follow-up period, 2,348 cases of oesophageal cancer were recorded among the participants.

The analysis showed that the risk increased with the temperature of the drinks.

Those who preferred hot drinks had nearly double the risk of oesophageal SCC compared to those who liked warm drinks. The risk was more than three times higher for those who liked their drinks very hot.

The researchers found that how often people drank hot beverages was also linked to the risk.

After considering temperature, participants who drank six or more hot drinks daily had a 71 percent higher risk of oesophageal SCC compared to those who drank fewer than six.

Why temperature might matter

Keren Papier, a senior nutritional epidemiologist at the University of Oxford and the lead author of the study, said the findings add to previous evidence connecting very hot drinks with oesophageal cancer.

Earlier research mainly focused on people in South America, Asia, and the Middle East, where drinking habits are different from those in Western countries.

Ms Papier said the new findings give evidence based on typical drinking habits in the UK, where tea and coffee are popular.

The researchers noted that the link between temperature and risk was not affected by whether participants added milk to their drinks, as long as the drinks remained hot.

Ian Johnson, an emeritus fellow at the Quadram Institute in England, also shared his thoughts. He said that hot liquids could damage the cells lining the oesophagus and cause inflammation, which might explain the link.

He advised people to let hot drinks cool down before drinking them.

Study does not prove direct cause

The researchers warned that the study did not prove that hot drinks directly cause oesophageal cancer.

One limitation was that participants did not measure the actual temperature of their drinks. They described them based on how hot they felt.

Muy-Teck Teh, a professor of molecular oral oncology at Queen Mary University of London, said that people's different sensitivities to heat mean the findings should be seen as a link, not proof that hot drinks cause cancer.

The researchers suggested that letting drinks cool, adding milk or cold water, or simply waiting before drinking could lower exposure to high temperatures.

Global issue

Oesophageal cancer is still a big health problem worldwide.

The IARC reported about 604,000 new cases and 544,000 deaths from oesophageal cancer globally in 2020.

The agency expects that annual cases could reach one million by 2040, which would be an increase of more than 50 percent.

However, the researchers mentioned that the overall risk of developing oesophageal cancer remains relatively low.

The study suggests that for those who enjoy tea or coffee, letting the drink cool before consuming it could be a simple way to avoid long exposure to very hot liquids.