Tea Drinkers Reap Blood Pressure Benefits
Drinking a Half-Cup of Tea per Day Cuts Hypertension Risk in Half
July 26, 2004 -- Drinking as little as a half-cup of green or
oolong tea per day may lower the risk of high blood pressure by nearly 50%,
according to a new study of Chinese tea drinkers.
Researchers found that men and women who drank tea on a daily
basis for at least a year were much less likely to develop hypertension than
those who didn't, and the more tea they drank, the bigger the benefits.
Tea is the second most consumed beverage in the world. Water is
Hypertension, or high blood pressure, is the most common form
of heart disease and affects about 20% of the adult population in many
countries. The condition is associated with stroke, heart failure, and kidney
dysfunction and is a major risk factor for heart-related death.
"A link between tea drinking and blood pressure reduction
has been postulated for decades in general health care in Chinese
populations," write researcher Yi-Ching Yan, MD, MPH, of the medical
college of National Cheng Kung University in Taiwan, and colleagues.
In recent years, researchers say there has been growing
interest in exploring the role of antioxidant compounds called flavonoids found
in tea that may protect against heart disease.
But researchers say few studies have examined the long-term
effects of tea drinking on the risk of hypertension, and the results so far
have been conflicting. They say this study is the first on the issue to use a
large number of people and detailed information about tea consumption and other
lifestyle and dietary factors associated with hypertension risk.
Drinking Tea Lowers Blood Pressure
In the study, which appears in the July 26 issue of The
Archives of Internal Medicine, researchers looked at the effect of tea
drinking over the past decades on the risk of developing high blood pressure in
1,507 Chinese men and women living in Taiwan who had no previous history of
high blood pressure.
Because the size of the teacup used varies widely in Chinese
culture, the participants were asked to provide details about what kind of cup
was used, how the tea was prepared, the amount drunk, and the frequency per
week in order to calculate the average tea consumption per day.
Researchers also collected information about the kind of tea
(green, black, or oolong) drunk and how long the participants had been tea
drinkers. Green, oolong, and black teas are derived from the same plant. It is
the processing of the leaves from the Camellia sinensis that determines
the type of tea and the flavonoid content.
The study showed that about 40% of the participants were
habitual tea drinkers and had been drinking at least a half-cup of tea per day
for one or more years. More than 96% of tea drinkers drank green or oolong