Green Tea for Heart Disease
Polyphenols and Green Tea
Tea contains compounds called polyphenols and flavonoids, the most active of which is epigallocatechin gallate (EGCG), which works to reduce oxidative damage from free radicals - Read more on these compounds in the article Benefits of Green Tea.
Catechins should be considered right alongside of the better-known antioxidants like vitamins E and C as potent free radical scavengers and health-supportive for this reason.
Flavonoids also improve the ability of blood vessels to dilate and contract and may have some anti-clotting benefits.
While this may be true for black tea as well, green tea seems to be more effective. Green tea is made with leaves that have undergone very little fermentation and have retained the full antioxidant power.
A Dutch study of nearly 5,000 people found that those who drank a cup and a half a day had about half the risk of heart attack compared with people who drank none.
If the tea drinkers did have a heart attack, they were only 1/3 as likely to die from it as non-tea drinkers.
Meanwhile, a study of 1,900 people who already had heart attacks found that heavy tea drinkers (14 or more cups a week) were 44% less likely to die in the 3 1/2 years following their attacks than non-tea drinkers.
Green Tea: The "Japanese Paradox"
In the previous article of this series we read about the "French Paradox".
For years, researchers were puzzled by the fact that, despite consuming a diet rich in fat, the French have a lower incidence of heart disease than Americans.
The answer was found to lie in red wine, which contains resveratrol, a polyphenol that limits the negative effects of smoking and a fatty diet.
In a 1997 study, researchers from the University of Kansas determined that EGCG in green tea is twice as powerful as resveratrol, which may explain why the rate of heart disease among Japanese men is quite low, even though approximately 75% are smokers. This is why I've called it the "Japanese paradox".
The Health Benefits of Green Tea Heart Disease
More evidence for the beneficial effect of green on tea heart disease has emerged in a new study reported in the latest issue of European Journal of Cardiovascular Prevention and Rehabilitation.
The study found that the consumption of green tea rapidly improves the function of cells lining the circulatory system; damage to cell walls of the arteries is a key event in the progression of atherosclerosis (follow the link to read more).
The study, performed by Dr Nikolaos Alexopoulos and colleagues at the 1st Cardiology Department, Athens Medical School in Greece, was a randomized trial involving the diameter measurement (dilation) of the brachial artery (the major blood vessel of the upper arm) of healthy volunteers on three separate occasions - after taking green tea, caffeine, and hot water (for a placebo effect). The measurements were taken at 30, 90 and 120 minutes after consumption.
Results showed that brachial artery dilatation increased significantly after drinking green tea, with a peak increase of 3.9 per cent 30 minutes after consumption. The effect of caffeine consumption (or hot water) was not significant.
While black tea has been associated with improved short and long-term endothelial performance, this is the first time that green tea has been shown to have a short-term beneficial effect on the large arteries.
Another study has already shown that green tea reverses endothelial dysfunction in smokers.
"These findings have important clinical implications," says Dr Vlachopoulos. "Tea consumption has been associated with reduced cardiovascular morbidity and mortality in several studies. Green tea is consumed less in the Western world than black tea, but it could be more beneficial because of the way it seems to improve endothelial function".
Even Better for Women?
If you are a regular green tea drinker your chances of dying from cardiovascular disease is probably 25% less than most other people who are not regular drinkers, according to a new study by scientists at Tohoku University, Japan.
Team leader, Dr. Shinichi Kuriyama came to the conclusion that green tea consumption may prolong a person's life by protecting him/her from cardiovascular disease.
The researchers did find, however, that consuming lots of green tea regularly seems to help women more. Women who drank 5+ cups per day were 31% less likely to die from cardiovascular disease compared to the less than 1 cup-per-day women.
Green Tea Anti-Thrombotic Effect
Already way back in 1967, the British scientific journal Nature carried some extraordinary photos of the aorta of rabbits given a high-fat, high cholesterol diet plus either water or tea to drink.
The aortas of the tea-drinking rabbits were much less scarred and ravaged by the high-fat diet.
Tea, concluded the researchers from Lawrence-Livermore Labs in California, had prevented much of the arterial damage.
They were inspired to do the experiments after noticing that the arteries of the Chinese-Americans who regularly drank tea exhibited only 2/3 as much coronary artery damage and only 1/3 as much cerebral artery damage at autopsy as Caucasian coffee drinkers.
Their suggestion that mysterious compounds in tea could keep blood vessels from clogging was ahead of its time.
You'll be pleased to know that science has finally caught up.
Much research reveals that tea protects arteries by influencing blood-clotting factors.
Tea chemicals can reduce blood coagulability, prevent platelet activation and clumping, increase clot-dissolving activity and decrease deposits of cholesterol in artery walls - all of which help fend off artery damage.
A pioneer in tea and atherosclerosis, Lou Fu-qing, M.D., professor and chairman of the Department of Internal Medicine at Zhejiang Medical University in China, has studied the effect of tea chemicals on heart-attack victims.
Dr. Lou believes that pigment from common black tea or Asian-style green tea thwarted patients' platelet clumping (also thromboxane production) and improved their clot-dissolving functioning.
Surprisingly, he said both ordinary black tea and green tea worked equally well in this case.
Scientists at Japan's Ito-en Central Research Institute also noted that catechin in tea blocked the clumping of platelets just as strongly as aspiring did.
Tea also appears to block LDL cholesterol's stimulation of the of the proliferation of smooth muscle cells on the artery walls; such cell growth fosters build-up of arterial plaque.
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