Recent research indicates that tea may work against heart attacks,
stroke, and thrombosis. Tea contributes to this in several ways. It
does so in general way through its role as gentle stimulant to the
heart and circulatory system. Then, second, it strengthens and keeps
the blood vessel walls soft. Third, there is evidence that the
phenols in tea inhibit the absorption of cholesterol in the
digestive tract, which could help the absorption of cholesterol in
the digestive tract, which could help decrease the cholesterol in
the bloodstream. Fourth, it may decrease the blood's tendency to
form thrombi, or unwanted clots. Often several of these functions
operate together against stroke or heart attack. Strokes and
thrombosis often occur because the blood vessels have lost their
elasticity. Rutin has long been prescribed to keep these walls soft.
One study found that feeding rabbits 3% oolong tea had nearly the
same effect on the blood vessels as taking rutin. (Institute of
Traditional Chinese Medicine and Pharmacology, Fuzhou, Fujian
province.) In both China and other countries it was at one time
believed that green tea contained a substance known as vitamin P
which worked with vessels, preventing leakage of blood nutrients. A
supplement called bioflavonoid, made from citrus rinds and with
characteristics similar to flavanols or catechins, was popular among
nutrition buffs. Later research concluded that it was not vitamin P
performing this function, but something else, and the U.S. Food and
Drug Administration prohibited the sale of bioflavonoid, saying they
were worthless.
Something in tea, however, may still be the answer. Tea catechins
were used with success in cases of hypertension to inhibit the
action of an enzyme that constricts blood vessels.
Other tests by the Fuzhou researches found that in patients with
hypertension, coronary heart disease, atherosclerosis, or a high
lipid level, drinking oolong tea (while taking no medicines) helped
decrease blood viscosity, improve microcirculation, and prevent
aggregation of blood platelets, which leads to unwanted clotting.
Where thrombosis, or a clot, did occur, it took longer to form, and
was of shorter duration.
