Green Tea May Cut Risk of Cancer, Study Shows
The Japanese fondness for green tea may explain why Japanese men can smoke more than American men yet are less likely to get lung cancer, researchers said Monday.
Their laboratory study found that consumption of green tea cut the lung cancer rate by 45% in mice exposed to one of the most potent cancer-causing agents in cigarette smoke.
Other studies on lab animals suggested that drinking green tea could reduce stomach and liver cancer rates, the researchers told a meeting of the American Chemical Society here.
The finding is too preliminary for researchers to recommend that people begin drinking green tea, said Allan H. Conney, director of the Laboratory for Cancer Research at Rutgers University in New Jersey.
“It’s still too early to say what the significance of this is for humans,” said Conney, who is studying how green tea and other foods relate to cancer rates in animals. “My opinion is we should not ingest large amounts of green tea.”
Fung-lung Chung of the American Health Foundation in New York agreed that more research had to be done to confirm the cancer-preventing effect of green tea, but he said one or two cups a day “wouldn’t do any harm.”
A researcher from the National Cancer Center Research Institute in Tokyo was more sanguine about the use of green tea.
“We would like to think drinking green tea may be one of the most practical cancer preventions at the moment,” Hirota Fujiki said.
Green tea is made from the same plant as the black tea commonly consumed in Western countries, Conney said, but green tea undergoes less processing. Light processing converts it into Chinese oolong tea; more extensive processing produces black tea, Conney said.
Conney has shown that green tea can slow the formation of skin cancer tumors in mice exposed to harmful ultraviolet radiation. In other experiments, it also inhibited formation of stomach and lung cancer tumors in mice, he said.
Fujiki said that populations studies have shown low cancer rates in Shizuoka Prefecture, where green tea is produced and people drink far more of it than elsewhere in Japan.
