Researchers have studied green tea in cancer prevention because they suspect that the drink's antioxidants may protect against the deadly disease. In particular, it may include compounds that fight bacteria that have been linked to stomach cancer.

However, previous studies were inconsistent, researchers write their report in the journal Gut. To get a better sense of green tea's potential effects, Dr. M. Inoue, at the National Cancer Center in Tokyo, examined six older studies.

Together, these studies involved more than 219,000 men and women 40 years and older, who were followed from about 7 years to more than 11 years. Overall, about four in five of the participants reported drinking green tea daily, with about a third drinking five or more cups per day.

During follow-up, about 2500 of the approximately 100,000 men, and about 1000 of the more than 118,000 women in the studies developed stomach cancer.

The researchers found no link between more tea drinking and reduced stomach cancer risk among men.

The 20 percent reduced stomach cancer risk they saw among women drinking 5 or more, versus 1 or less, cups of green tea daily remained true even after the researchers took smoking into account. They note, however, that the decreased risk only applied to cancers in certain parts of the stomach.

While the study does not prove a cause-effect relationship, the authors suggest more research to figure out whether drinking green tea actually decreases the risk of stomach cancer, or whether women with a lower risk only happen to drink more of it.

SOURCE: Gut, September 9, 2009.