Drinking very hot beverages—at about 149 degrees Fahrenheit or hotter—probably can cause cancer of the esophagus, says a group of international scientists.
But they also say the finding is based on limited evidence.
The World Health Organization asked the 23 scientists to evaluate whether coffee, maté or very hot beverages could be carcinogenic.
The researchers said studies in Turkey, Iran, China and some South American countries where people typically drink tea or maté very hot show the risk of esophageal cancer rises with the temperature of the beverages.
“These results suggest that drinking very hot beverages is one probable cause of esophageal cancer and that it is the temperature, rather than the drinks themselves, that appears to be responsible,” said Christopher Wild, director of the WHO’s International Agency for Research on Cancer.
Coffee, maté, water and cancer
The findings, published in The Lancet, will relieve many drinkers of coffee and maté, an infusion made with dried leaves of a species of holly. Researchers found “no conclusive evidence” that drinking coffee itself has a carcinogenic effect. The same is true of maté, cold or at room temperature.
Some of the studies analyzed by the working group found an increased risk of esophageal cancer for those who drink very hot tea. And experiments with animals showed water at 149 degrees or hotter “can act as a tumor promoter,” the work group reported.
The last time the IARC studied the carcinogenicity of coffee, in 1991, the beverage was classified as “possibly carcinogenic to humans” based on some limited evidence of an association with bladder cancer. But for the re-evaluation, scientists tapped into a much larger database of well-controlled scientific studies.
In the end, they concluded drinking coffee was “unclassifiable” for its carcinogenicity. Indeed, a recent study from Harvard suggested that drinking coffee can help people live longer.
What is esophageal cancer?
The esophagus is the hollow tube that moves food and liquid from the throat to the stomach. The two most common forms of esophageal cancer are squamous cell carcinoma, in which malignant cells form in the lining of the esophagus, and adenocarcinoma, which begins in glands and usually forms in the lower esophagus, near the stomach.
Use of tobacco and heavy use of alcohol also can increase the risk of esophageal cancer. Signs of esophageal cancer include:
- Painful or difficulty swallowing
- Weight loss
- Pain behind the breastbone
- Hoarseness and a cough
- Indigestion and heartburn
You can read the hot beverage study at The Lancet (registration required). You can read the IARC’s statement on the study here.
If you are wondering about how safe it is to drink coffee or other beverages, or your risks of developing cancer of the esophagus, check with your health care provider. If you don’t have a provider, you can find a Providence provider here.