Coffee has long been praised for its brain-boosting abilities and, according to some studies, may contain properties that reduce the risk of type 2 diabetes. Despite its reported benefits, the WHO’s cancer research agency, International Agency for Research on Cancer (IARC), previously believed coffee posed a carcinogenic threat to drinkers. The IARC has since reversed its warnings, saying there is no conclusive evidence that coffee may be carcinogenic. In fact, some studies have shown coffee may even reduce the risk of developing certain forms of cancer.
Pancreatic cancer was previously linked to coffee consumption, but in defiance of these older reports, the studies found there was no consistent link between coffee intake and the risk of cancer. A group of 23 scientists, convened by the IARC, reviewed more than 1,000 studies in humans and animals and found “inadequate evidence” of the carcinogenicity—the ability or tendency to produce cancer—of drinking coffee. Coffee drinkers rejoice!
Those who enjoy their cup of Joe at scalding hot temperatures, however, may have something to worry about. This same re-evaluation of studies, which freed coffee of its carcinogenic connotation, did find a link between hot beverages and cancer-causing properties.
A positive association emerged between esophageal cancer and drinking beverages heated to 65 degrees Celsius (150 degrees Fahrenheit) or higher. The study included an evaluation of drinks including coffee, tea, water and other beverages.
A separate 2018 study of 456,155 people between the ages of 30 and 79 reached a similar conclusion. Researchers linked consumption of hot tea with esophageal cancer in those who smoked or drank alcohol daily. During the nine-year study, participants were asked to describe the temperature of their regular cups of tea as "warm," "hot" or "burning hot." Compared to people who drank tea infrequently and consumed less alcohol, those with the highest cancer risk sipped their tea burning hot and had at least 15 grams of alcohol every day. People who drank burning-hot tea and smoked also had a higher risk of esophageal cancer.
Worldwide, esophageal cancer is the eighth most common type of cancer, responsible for about 5 percent of all cancer related deaths. Although the proportion of esophageal cancer cases related to drinking extremely hot beverages is unknown, a majority of esophageal cancer cases occur in parts of Asia, South America and East Africa, where it is common to drink very hot beverages. More research is needed to determine the cause of high rates of esophageal cancer in these regions.
It’s believed that hot liquids have the potential to damage cells in the esophagus, which could in turn, prompt changes that lead to cancer.
The evaluation of hot beverages and esophageal cancer is based on limited evidence, and more research is needed, according to the WHO’s official spokesperson, Gregory Hartl.
