"What we found was that was less prevalent in green tea drinkers, suggesting
that regular green tea intake may be playing a protective role against the
development of in Japanese," the study's lead author, Dr. Yukihiko Momiyama of
the National Defense Medical College in Saitama, told Reuters Health.
Green tea is becoming more and more popular in the US and other Western
countries, but the drink is the most common beverage in Japan, according to
Momiyama. Heart disease is less common in Japan than in the West, and
researchers have been trying to figure out why.
Although there are probably many factors that explain the difference in heart
disease rates, some scientists suspect that green tea may boost heart health
because it contains high levels of substances called flavonoids. These plant
compounds, which are found in a variety of fruits and vegetables as well as in
tea and red wine, are thought to boost health in part by combating oxidation, a
process in which cell-damaging substances called free radicals accumulate.
Oxidative damage can be caused by outside factors, such as cigarette smoking, or
by factors on the cellular level. Oxidation is suspected of increasing the risk
of heart disease, stroke and several other diseases.
Several studies have found that people who consume lots of flavonoids are
less likely to die from coronary artery disease, and another study linked high
flavonoid consumption to a reduced risk of heart attack.
In the new study, Momiyama's team did not detect a link between the number of
cups of green tea a person drank each day and the risk of coronary artery
disease or the severity of artery disease. However, people who drank green tea
were less likely to have a heart attack, the authors report in the November 15th
issue of the American Journal of Cardiology. In the study, people who drank at
least one cup of green tea per day were 42% less likely to have a heart attack
than people who did not drink green tea.
The people in the study did not represent a cross-section of the Japanese
population. The 393 patients were undergoing a procedure called angiography to
see whether they had coronary artery disease. Many of the participants had risk
factors for heart and artery disease, including high blood pressure, high
cholesterol and diabetes.
