Coffee cleared as a carcinogen
Coffee can be enjoyed with impunity as long as you don’t drink it too hot, is the take home message from a landmark Lancet study.
An international working group of 23 scientists has evaluated the carcinogenicity of drinking coffee and very hot beverages.
It found no conclusive evidence that coffee causes cancer. However, the experts did find that drinking very hot beverages above 65 degrees celsius probably causes cancer of the oesophagus in humans.
The results suggest it is the temperature rather than the drinks themselves that have adverse effects.
To reach their findings, the working group, convened by the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), reviewed more than 1,000 human epidemiological studies and animal experimental studies.
Not only did IARC’s report let coffee off the hook as cause of cancers of the breast, pancreas and prostate, it found the popular brew may have protective benefits including reducing the risk of liver and endometrial cancer.
The results contradict previous work that suggested coffee was a potential carcinogen.
“Coffee had previously been thought to be possibly associated with bladder cancer,” says Dr Ian Olver who is Professor of Translational Health Research and Director of the Sansom Institute for Health Research at the University of South Australia.
“This shows how just having a small number of studies can cause uncertain results which are clarified by considering a very large number of studies. It also shows that if other known causal factors are not controlled for, in this case smoking, the cause of the cancer can be attributed to an agent that is merely associated with the cancer but does not cause it.”