"Stomach cancer is a major problem in the world, and this may be a way to help prevent it," says Zuo-Feng Zhang, MD, PhD, director of the cancer epidemiology training program at the University of California at Los Angeles (UCLA) School of Public Health, and an author of the report in IJC.

The researchers obtained answers to detailed questionnaires filled out by 133 stomach cancer patients, 166 patients with chronic gastritis (constant inflammation of the stomach that can lead to stomach cancer) and 433 healthy people in Yangzhong City in southeast mainland China. The city has one of the highest rates of stomach cancer in the world.

After adjusting for other factors that can influence cancer rates, such as tobacco use, alcohol use, and obesity, the researchers found that those who regularly drank green tea were 48% less likely to develop stomach cancer, and 51% less likely to develop chronic gastritis than those who did not regularly drink green tea.

Some earlier studies suggested green tea might reduce stomach cancer risk, but the UCLA researchers say theirs is the first to show it may also reduce the risk of chronic gastritis.

"And there was a dose-response relationship to stomach cancer — the more they drank it and the longer they drank it regularly, the less likely they were to develop stomach cancer," notes V. Wendy Setiawan, a PhD student in the UCLA epidemiology department who was the study’s lead author.

The researchers suggest a next step might be intervention studies to learn if green tea can help prevent stomach cancer in those who already have chronic gastritis, or help prevent chronic gastritis in people at high risk for it, thereby reducing stomach cancer rates.

"This is an interesting study, suggesting that frequent green tea consumption reduces stomach cancer risk, which is a finding consistent with some — but not all — earlier studies," says Eric Jacobs, PhD., an epidemiologist with the epidemiology and surveillance research department of the American Cancer Society (ACS).

"But I would caution that this study may not be generalizable to the US," adds Jacobs, "It was done in one of the world’s highest-risk areas for stomach cancer, where the causes of stomach cancer — and so, the ways to prevent it — may be very different than in the US, where the rates are many, many times lower," he notes.

Jacobs notes that in many less developed areas of the world, high rates of stomach cancer are due in part to high rates of infection with a bacteria called H. pylori. In addition, these areas may have higher stomach cancer rates because of a lack of refrigeration, leading people to consume fewer fruits and vegetables and to rely on salting and pickling to preserve foods.

"This is worthwhile research, worth pursuing, but for now, the best advice concerning nutrition and cancer prevention is still to consume a diet high in plant foods and low in animal fats," notes Jacobs. "We know that works."