WASHINGTON – Seated among the bustling lunchtime crowd at the gourmet tea shop Teaism,Shizuka Ogak,27,poured herself a steaming cup of green tea.
She said she usually drinks about six cups a day,but that it would probably be more that day because at just past noon,she was already on her fourth cup.
Ogak,of Bethesda,Md.,said she thinks “ryokucha” – the Japanese word for green tea – keeps her healthy,but she is not sure. Like many Japanese,she just grew up drinking it.
“We drink green tea kind of like Americans drink soft drinks,I think,” said Ogak,who is an administrative officer at the Japan International Cooperation Agency. “I'm pretty sure green tea is better for the body.”
Research trying to pinpoint the health the benefits of green tea have exploded in past years,spurring debate among scientists about its link to cancer prevention.
Green tea probably has some cancer-fighting benefits,but researchers still do not know how much or what types of cancer it might prevent,according to a report released Thursday by a charity organization that studies the effects of diet on cancer prevention.
The announcement by the American Institute for Cancer Research came two weeks after the U.S. Food and Drug Administration's announcement that green tea does not likely help prevent breast,prostate or any other type of cancer.
“The FDA also concluded that existing evidence does not support qualified health claims for green tea consumption and a reduced risk of any other type of cancer,” the agency said in a statement.
In contrast to previous research and the FDA,the American Institute for Cancer Research study found that a substance in green tea intercepts one of the proteins that activate cancer cells in some cases,stopping the process at an earlier stage than researchers assumed. The study results were published in the April issue of Biochemistry,a peer-reviewed science journal.
“We don't know too much about the dosage of green tea,that is,how much green tea it might take to affect your health,” said Jeffrey R. Prince,vice-president for education and communications at the American Institute for Cancer Research. He said that adding green tea to a diet of vegetables and fruit would have “no ill effects and perhaps some benefit.”
“The reason we are focusing on green tea is that the scientists that we have brought together this year are talking about green tea,” Prince said. “They are interested in the possibility.”
The American Institute for Cancer Research also released a survey that found Americans drink far less green tea than Japanese do. The survey combined data from an epidemiology study – a study of populations over an extended period – of Japanese food intake and a phone survey of 1,016 Americans,to compare green tea intake.
The survey reported that 68 percent of Americans said they drank green tea rarely or never,compared to 8 percent of the Japanese people who said the same.
Despite numerous animal studies suggesting that green tea targets certain forms of cancer,only limited human research has been done. And because Americans do not drink much green tea,it would be difficult to study its effects,said Marji McCullough,a nutritional epidemiologist for the American Cancer Society.
“The bottom line is that this is a different study design that adds a piece to the puzzle. But to see the full picture we need more in humans,” McCullough said.