Green tea consumption was inversely associated with all-cause and
cardiovascular mortality.
In vitro and animal studies suggest that green tea polyphenols may
reduce the progression of cardiovascular disease and cancer, but the
results of small studies in humans have been inconsistent. This new
prospective cohort study involved 40,000 adults (age range, 40–79)
from a Japanese district where 80% of the population drinks some
green tea. The participants had no history of stroke, coronary heart
disease, or cancer. Diet was assessed with self-reported food
frequency recall.
During a maximum follow-up of 11 years, 2931 deaths occurred. After
adjustment for nearly 20 demographic, lifestyle, and medical risk
factors, green tea consumption was associated with significantly reduced
all-cause and cardiovascular mortality, but not cancer mortality. For
example, compared with subjects who drank less than 1 cup of green
tea per day, those who drank 5 cups or more per day had hazard ratios
of 0.84 for all-cause mortality and 0.74 for cardiovascular
mortality. The protective effect was generally stronger in women than
in men. Similar relations were not found for black or oolong teas.
Comment: That so many people in the study area drink some amount of
green tea strengthens the dose-dependent relation found in this
study. The authors suggest several possible biologic mechanisms, particularly
radical scavenging and other antioxidant benefits, to explain this
association.
— Thomas L. Schwenk, MD
Published in Journal Watch September 28, 2006
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