Hot drinks linked to increased cancer risk, study finds
A study of nearly a million people has found new evidence to suggest that drinking scalding hot coffees and teas could significantly increase a person’s risk of getting cancer in their esophagus, reports BritPanorama.
Drinking these beverages very hot, rather than warm, is associated with a three-fold risk of esophageal cancer, according to the study, conducted in the UK and published Tuesday in the International Journal of Cancer. The finding applies specifically to esophageal squamous cell carcinoma (SCC), the most common form of esophageal cancer worldwide.
The esophagus, also known as the food pipe, is a muscular tube that passes food and drink from your mouth to your stomach. Globally, there were about 604,000 new cases of esophageal cancer and about 544,000 deaths from esophageal cancer in 2020, according to the World Health Organization’s cancer agency, the International Agency for Research on Cancer (IARC). The agency estimates that global cases will rise by more than 50%, to almost a million new cases a year by 2040.
In the UK, there are around 9,500 new cases each year, according to Cancer Research UK. However, an estimated 14% of new esophageal SCC cases in the country could be avoided if individuals drank their teas and coffees at lower temperatures, the researchers from the UK’s University of Oxford said in the study, which is the largest of its kind.
The researchers analyzed data from nearly 980,000 middle-aged adults in the UK who were asked questions about their hot drink consumption habits, including whether they preferred their drinks “very hot,” “hot,” or “warm,” or if they “do not drink hot drinks,” or “prefer not to answer.” They were also asked how many hot drinks they consumed each day, with options such as “fewer than 6 hot drinks per day” or “6 or more hot drinks per day.”
All the participants were from two large cohorts, the Million Women Study and UK Biobank, which both routinely log participants’ health information. Across the cohorts, 2,348 incidents of esophageal cancer occurred during an average follow-up period of 14.2 years and 11.1 years, respectively. The researchers found that just under half of the participants reported consuming six or more hot drinks per day, and approximately 15% said they preferred their drinks very hot.
The risk of esophageal SCC increased with the preferred drink temperature, with those who liked their drinks hot having almost twice the cancer risk of those who preferred them warm. For those who liked their drinks very hot, the risk was more than three-fold. Drinking six or more hot drinks a day, compared with fewer than six, was associated with a 71% higher risk of esophageal SCC.
“This is the largest study to date, and it does really add to the evidence that drinking very hot and hot beverages could increase the risk of this type of cancer,” lead study author Keren Papier, a senior nutritional epidemiologist at Oxford Population Health, said.
Drinking very hot beverages was classified as probably carcinogenic to humans by the IARC in 2016, which defines “very hot” beverages as being at temperatures above 65 degrees Celsius, or 149 degrees Fahrenheit. Previous studies were mostly conducted in South America, Asia, and the Middle East, where drinking cultures differ significantly.
People in the UK often add milk to their hot beverages; however, the researchers found that the cancer risk did not change based on whether participants added milk to their drinks or not, provided the drinks were still hot. Papier emphasized that this study finds “evidence from typical drinking habits in the UK,” where “most people are consuming tea or coffee daily,” highlighting that how these drinks are consumed matters.
Relative risk remains low
Despite the findings, the chance of being diagnosed with esophageal cancer remains relatively low. The cancer accounts for only 2% of cancer cases in the UK, where people have around a 1% lifetime risk of being diagnosed with it, according to Cancer Research UK. In the US, esophageal cancer is estimated to have constituted just 1.1% of new cancer cases this year, according to the National Cancer Institute.
For those who enjoy hot drinks and are concerned about these findings, Papier suggests a simple step: let the drink cool down. Cooling can be achieved by letting it sit, adding milk or cold water, blowing on it, or taking sips. “There is prior evidence that hot liquids damage the cells lining the oesophagus and can cause inflammation,” stated epithelial physiologist Ian Johnson, who was not involved in the study.
Johnson expressed that it would be prudent for people to consume cooler drinks, specifically those below 65°C. However, he noted the challenge of changing habits for those who favour hot drinks.
While the researchers could not explore the exact temperatures of the drinks consumed by participants, the varying perceptions of heat among individuals made it difficult to determine whether self-reported heat levels were consistent with specific temperature figures. Physiologist Muy-Teck Teh stated that perceived drink temperatures were self-reported, cautioned against interpreting results as causal proof.
Papier highlighted that smoking remains the biggest risk factor for this form of cancer, which shows higher incidences in Eastern Asia and Southern and Eastern Africa, where alcohol consumption and indoor air pollution likely contribute to the issue.
The implications of this research underscore the importance of public health messages regarding drink temperature, especially in a culture where hot beverages are prevalent.
