Update: In March 2019, a study published in the International Journal of Cancer suggested an association between hot tea consumption and esophageal squamous cell cancer. Dr. Molena explains that this study, conducted in a specific region of Iran, does not contradict the conclusions discussed in the story below. “In this case, the temperature of the tea was actually measured rather than estimated by the individuals, which is a strength of the study. The weakness of the study is that most people in this region drink tea and there isn’t a control group available. The higher rate of esophageal cancer might be due to other environmental factors rather than tea temperature.”
Original post: It seems that almost every dietary habit has at some point been linked to an increased risk of cancer. In recent years, the idea has emerged that drinking very hot beverages could contribute to esophageal cancer. This is due mainly to a 2016 statement from the World Health Organization (WHO) and a study from China published in the Annals of Internal Medicine in February 2018.
We spoke with Daniela Molena, Director of Memorial Sloan Kettering’s Esophageal Surgery Program, to learn what is actually known about the topic from research and whether we should be worried about drinking hot beverages.
What gave rise to the idea that hot drinks could increase esophageal cancer risk?
This idea is not new. It goes back to at least the 1930s. The theory has been that hot liquid could destroy the inner lining of the esophagus, requiring the cells to continually regenerate. During this process, there is a greater chance that something can go wrong and turn normal cells into cancer cells. A long time ago, animal studies suggested that very, very hot beverages could cause this damage. But this was at higher temperatures than people would usually drink liquids.
Besides, if this type of damage led to esophageal cancer, you would expect to see higher rates of mouth cancer because the mouth lining is exposed to the liquid first — and that doesn’t happen.
What did the 2016 WHO statement and the 2018 study from China actually claim?
I think both were a bit misleading, at least as it applies to people in the United States and Europe. The type of esophageal cancer that is far more common in the United States is adenocarcinoma. The supposed link with hot beverages related to an esophageal cancer called squamous cell cancer. This type is prevalent in many other parts of the world — China, other parts of Asia, India, South America, and Africa — but is rare in the United States and Europe.
Even for squamous cell cancer, the evidence is not clear. In both cases, the suggested link was between squamous cell esophageal cancer and consumption of very hot tea. The WHO statement was based on a study looking at people who drank a variety of hot tea consumed in these other countries. These populations tend to have more exposure to other factors that raise the risk of cancer, such as smoking, alcohol consumption, cooking over an open fire, and environmental contaminants. The presence of these other factors makes it hard to be certain that hot tea alone was responsible for the increased risk.
The China study had a similar issue. It found a higher incidence of esophageal cancer in people who drank more hot tea but only in those who also drank alcohol every day or smoked. It is plausible that drinking hot beverages might raise esophageal cancer risk if combined with smoking or alcohol consumption. But the study did not find that hot tea alone had that effect.
Another problem with the China study was that it asked people to rank for themselves how hot the tea that they drank was. There was no actual measure of temperature. What one person may consider “very hot” may not hold true for someone else. In that sense, it’s really not a very scientifically rigorous study.Back to top
What’s the most important point that people should remember about hot beverages and esophageal cancer?
There has never been solid evidence that drinking hot liquids alone will increase esophageal cancer risk. At this point we have only the suggestion that it might make the risk higher in people who smoke or consume alcohol.
I would advise people to focus instead on factors that are very solidly linked to a higher risk of developing esophageal cancer. For squamous cell, it’s smoking and alcohol. For adenocarcinoma, the most common risk factors are obesity and gastroesophageal reflux disease.
In short: Cut down on these other habits and drink all the reasonably hot liquids you want.Back to top