The International Agency for Research on Cancer (IARC), part of the World Health Organization, said on Wednesday that coffee cannot be classified as a carcinogen, based on a review of more than 1,000 studies.
The announcement marked a rare reversal for the Agency, which had previously described coffee as “possibly carcinogenic” in 1991 and linked it to bladder cancer.
Lyon-based IARC brought together 23 scientists to review studies on the cancer-related properties of both coffee and maté herbal tea.
It found that there is “no conclusive evidence for a carcinogenic effect” of coffee drinking and pointed to some studies showing coffee may actually reduce the risk of developing certain types of cancer.
However, the scientists did identify one surprising risk for coffee and tea drinkers. They said that drinking “very hot” beverages was “probably carcinogenic” because the practice was linked to oesophageal cancer in some studies.
But researchers say that may be caused by excessively hot beverages inflaming the lining of the throat – something that people could easily avoid by letting their hot tea or coffee cool off for a few minutes before drinking them.
The new monograph classifies hot drinks as group 2A, meaning they are “probably carcinogenic to humans”. IARC had previously put coffee as a “possible carcinogen” in its 2B category alongside chloroform, lead and many other substances.
Coffee and mate served cold are in group three, which means there is insufficient evidence to believe they cause cancer.
