Green tea may not offer any protection against throat cancer, a new study suggests, and drinking the beverage piping-hot may actually raise a person’s risk of the disease.

A number of studies have linked green tea - with its high content of antioxidant compounds called cathechins - to lower risks of certain cancers, including prostate, colon and breast cancers. Some studies have suggested this may hold true when it comes to cancer of the esophagus, but others have found no such benefit.

The new study, of 5,400 Chinese adults with and without esophageal cancer, found no evidence that those who regularly drank green tea had a lower risk of the disease.

There was, however, evidence that drinking tea at a high temperature may actually promote the cancer, the researchers report in the International Journal of Cancer.

They found that compared with adults who did not drink tea, those who boiled their tea water had two to three times the risk of esophageal cancer. There was no increased risk found among tea drinkers who used non-boiling water.

The findings add to those from a study published in March that linked hot beverages to a higher risk of esophageal cancer. Those researchers found that people who regularly drank their tea right after pouring had a greater risk of the disease than tea drinkers who liked to let the beverage cool for a few minutes.

It is not clear how hot beverages might promote esophageal cancer, but one possibility is that the repeated heat damages cells in the throat lining.

The bottom line is that people should take their liquids warm, but not steaming-hot, advised senior researcher Dr. Jinkou Zhao, of the Jiangsu Provincial Center for Disease Control and Prevention in China.

A number of studies, Zhao told Reuters Health, have suggested that regularly having hot liquids - including tea, coffee and soup - may raise the risks of both esophageal and stomach cancers.

While this study did not find a protective effective of green tea, Zhao noted, drinking green tea at a moderate temperature may still have health benefits, including lower risks of some cancers.

SOURCE: International Journal of Cancer, April 15, 2009.
By Amy Norton