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NOTES ABOUT TEA - GREEN TEA IS NEARLY MAGICAL! FROM LINUS PAULING DIET AND OPTIMAL HEALTH MEETING MAY 18-22, 2005 Remarks on flavanols - Dr. Katan
TEA
HELPS PREVENT COLON CANCER "Research shows that epigallocatechin-3-gallate
(EGCG), an antioxidative polyphenol
in tea, can inhibit the activity of the §-catenin/Tcf signaling
pathway in vitro. More than 80% of human colon cancers have a mutation
in the APC gene, and those that do not have mutations
in §-catenin. " update: A cup of tea may delay onset of Alzheimer's disease. Effects of green tea last a week, while black tea works only a day. Tea inhibits brain enzymes linked to the disease. Newcastle Univ. Study, Phytotherapy Research Online, Oct. 2004 TEA is currently unique as something one can consume. At the American Aging Association meetings during the summer of 2003, I heard many presentations with comments about tea. One study reported that animals who received the human equivalent of 4 cups of green tea per day lived 10% longer. This is the first legitimate report I have heard of anything we can eat that will prolong life span. Antioxidants like vitamin C and E reduce risk of disease, and genetic manipulation of DNA will extend life of creatures, but green tea is the only thing likely to conveniently extend life. This may relate to the fact that Chinese have been consuming green tea for thousands of years. In this essay, I highlight Proceedings of the Third International Scientific Symposium on Tea and Human Health, as published in The Journal of Nutrition 133:3242S-3318S (October, 2003). The key ingredient in tea is a class of compounds called flavonoids. Tea has been consumed since the beginning of its history 5,000 years ago. The polyphenolic flavonoids include catechins associated with antiangiogenic, antibacterial, anticarcinogenic, antiinflammatory, antithrombotic, antiviral, hypocholesterolemic, hypoglycemic and vasodilatory effects. Brief definitions: antiangiogenic - prevents growth of new blood vessels required by cancer tumors antibacterial - kills bacterial infections anticarcinogenic - blocks cancer formation antiinflammatory - prevents inflammation, which is currently held to be a key factor causing heart attacks antithrombotic - prevents blood clots, which leads to heart attacks and strokes antiviral - kills viruses hypocholesterolemic - reduces cholesterol hypoglycemic - reduces blood sugar levels. High blood sugar levels leads to adult-onset diabetes vasodilatory - relaxes blood vessels lowering blood pressure Tea may reduce the risk for cancer and heart disease. Medical costs of these are $157 billion per year, productivity costs are $352 billion per year.
THREE KINDS OF TEA - All real tea comes from Camellia sinensis. Other than water, it is the most widely consumed beverage in the world [how about substituting it for coke and pepsi when one is thirsty?]. Black is made via a postharvest "fermentation", an auto-oxidation catalyzed by polyphenol oxidase. Green tea is steamed shortly after picking to deactivate the polyphenol oxidase. Oolong tea is allowed to partially oxidize, half way between green and black. There
is no evidence to suggest any adverse consequences from tea consumption.. Bioavailability and antioxidant activity of tea flavanols after consumption of green tea, black tea, or a green tea extract supplement
As all of these contain different compounds, it is useful to consume some of all of them on a regular basis. But as a general rule of thumb, darker things (blueberries, tea, red wine, dark chocolate) are better for your health than lighter (white) things - white potatoes, white rice, white bread, white pasta. Other papers in this symposium describe the following: Mechanisms of cancer prevention by tea constituents - "the scientific evidence is strongest for the potection of DNA from oxidative damage" from antioxidants in tea. Black Tea Consumption reduces total and LDL cholesterol in mildly hypercholesterolemic adults.- it appears tea does reduce LDL levels The epidemiology of tea consumption and colorectal cancer - unfortunately, it does not presently appear protective. For likely mechanism of green tea action via EGCG, see J Biol Chem 277 (34): 30574-80 (Aug. 23, 2002)
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