Scientists have found further evidence that drinking coffee has health benefits, possibly protecting against certain cancers.

The study suggests that drinking more than four cups of coffee a day decreases the risk of developing certain cancers.

Mia Hashibe of the University of Utah, Salt Lake City compared the coffee-drinking habits of 5,139 cases with that of 9,028 case-control studies of head and neck cancers. From her analysis was revealed that people who drank more than four cups of coffee a day had a 39 per cent decreased risk of cancers of the oral cavity and pharynx combined, compared with those who didn’t drink coffee.

„Since coffee is so widely used and there is a relatively high incidence and low survival rate of these forms of cancers, our results have important public health implications that need to be further addressed”, Mia Hashibe said.

„What makes our results so unique is that we had a very large sample size, and since we combined data across many studies, we had more statistical power to detect associations between cancer and coffee.”

The findings were published online in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, and used studies from the International Head and Neck Cancer Epidemiology (INHANCE) consortium.

Although Mia Hashibe’s research shows this association between caffeine and cancer risk, the mechanisms involved are not known, or what dose of caffeine is healthiest. Researchers point out that coffee contains phenols, some of which are known to have antioxidant properties and others are thought to activate enzymes that help the body deal with carcinogens.

According to Ed Yong, head of health information at Cancer Research UK – „Coffee is a cocktail of hundreds of different chemicals and we don’t know which of these, if any, could affect the risk of cancer. You often only see benefits in people who drink a great deal of coffee. And studies like these rely on people with cancer remembering how much coffee they drank years ago. We now need studies that look at larger groups of initially healthy people to see if the amount of coffee they drink affects their cancer risk over time”.