Drinking green tea can substantially
cut the risk of dying from a range of illnesses,
a Japanese study has found.
The research, which looked at
over 40,000 people, found the risk of fatal cardiovascular
disease was cut by more than a quarter.
But British heart experts said
the benefits may be linked to the whole Japanese
diet, which is healthier than that eaten in the
west.
The work is published in the
Journal of the American Medical Association.
Tea is
the most consumed beverage in the world, aside
from water.
Three billion kilograms of tea
are produced each year worldwide.
Studies carried out in laboratories
and on animals have suggested green tea in particular
has extensive health benefits.
Women 'greater benefit'
In this study, which began in
1994, researchers from Tohoku University, looked
at how humans could benefit.
They examined data on 40,530
healthy adults aged 40 to 79 in north-eastern
Japan, where green tea is widely consumed.
Around 80% of people in the region
drink green tea, with more than half consuming
three or more cups each day.
The people in the study were
followed for up to 11 years (1995-2005), when
4,209 people died from all causes.
The researchers also looked at
seven years' worth of data (from 1995-2001) to
look at deaths from specific causes.
In that period, 892 people died
of cardiovascular disease (CVD) and 1,134 participants
died of cancer.
Compared with people who drank
less than one cup per day of green tea, those
who consumed five or more had a 16% lower risk
of dying from any cause during the 11-year study.
They also had a 26% lower risk
of dying from CVD in the seven years of follow-up.
There was no significant association
between green tea consumption and death from cancer.
Throughout the study, the benefits
of green tea appeared greater in women.
Those who drank five cups or
more of green tea each day had a 31% lower risk
of dying from cardiovascular disease compared
with those who had less than one.
But the study failed to find
a beneficial link between drinking black or oolong
tea and a reduced risk of dying from CVD.
'Low disease rate'
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 with 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."
