According to a Japanese study, there has been a significant reduction in the risk of deaths from several diseases, due to drinking of green tea.
A 25 % reduction in the risk of fatal cardiovascular disease was reported in this study conducted on more than 40,000 people. However, British heart experts feel that these benefits may be due to the whole diet of the Japanese that is much healthier than the diet in the west.
The findings of this study are published in the Sept. 13 issue of Journal of the American Medical Association.
Next to water, tea is the largely consumed drink in the world. Worldwide around 3 billion kilograms of tea is produced annually. The wide-ranging health benefits of green tea have been revealed by various studies conducted in laboratories and on animals.
The research team from Tohoku University in Sendai, Japan started the study in 1994, focusing on how man could benefit from green tea.
Green tea is largely consumed in north-eastern Japan. The researchers studied the data on 40,530 healthy adults aged 40 to 79 in this region.
Green tea is consumed by nearly 80% of the people here with over 50% consuming three or more cups each day. This study was conducted for 11 years (1995-2005), until then 4, 209 people had died from all causes. In search of specific reasons for death, the researchers scrutinized 7 years' data (1995-2001). Cardiovascular disease (CVD) was the cause of 892 deaths and cancer of 1,134 deaths, during that period.
In the 11-year study, a 16% reduction in risk of dying from any cause was noted in people who consumed 5 or more cups of green tea a day than those who took less than a cup a day. Also, a 26% reduction in risk of dying from CVD was noted. However, there was no major link between green tea consumption and death from cancer.
According to the study, women seem to be more benefited from the green tea than men. A 31% reduction of risk of death from CVD was noted in women who drank 5 or more cups of the green tea compared with those who had less than one.
However, there was no significant association between black or oolong tea consumption and reduction in risk of deaths from CVD, indicating the antioxidants specific to green tea could be the cause.
"This study serves as a tentative corroboration of what we thought — and hoped — we knew about green tea," said Dr. David Katz, a public health professor at Yale University School of Medicine and an ABC News contributor.
Katz explained that the antioxidants in green tea likely "sop up" the free radicals, allowing for a reduction in LDL ("bad" cholesterol) and an increase in HDL ("good" cholesterol).
Arterial plaque build up can be decreased by antioxidants and it can also help in better functioning of the blood vessels. In this manner, it reduces the risk of early death from CVD.
Dr Shinichi Kuriyama, who led the research, said: "The most important finding is that green tea may prolong people's lives through reducing the risk of cardiovascular disease."
But Ellen Mason, a cardiac nurse at the British Heart Foundation said, "The Japanese diet as a whole was particularly healthy, and the findings may not apply to people eating western diets.
"The rate of heart disease in Japan is already one of the lowest in the world, and the Japanese diet is believed to play a substantial role in keeping this low.
"Drinking 3-4 cups of green tea in parts of Japan is a daily habit.
"The average British diet contains more saturated fat than the average Japanese diet, and our levels of heart disease are relatively high compared to many other countries in the world.
"It is questionable whether drinking the same amount of green tea a day in the UK would have a significant impact on levels of heart disease."
She added: "Clinical trials are now needed to discover whether something as simple as green tea really can prevent deaths from heart disease."