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Green Tea

Green tea may be helpful to improve cognitive performance as well as to treat stomach disorders, vomiting, diarrhea and headaches. It is used as a diuretic and in combination products for weight loss. Green tea may be beneficial in solid tumor cancers and to reduce the risk of breast cancer, prostate cancer, colon cancer and gastric cancer. It may be beneficial to maintain remission in people with Crohn's disease, to prevent Parkinson's disease and to protect against heart disease, dental caries and kidney stones.

Green tea is also used to prevent skin damage and cancer related to ultraviolet (UV) radiation (e.g. sunburn) and other environmental causes. Green tea is different than black teas because it is not fermented. Polyphenols such as gallic acid and catechins such as epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) and epicatechin (EC), are abundant in green tea and are thought to be responsible for many of its proposed benefits.

Green tea also contains 2-4% caffeine or 10-80mg caffeine per cup. The caffeine in green tea acts as a central nervous system (CNS) stimulant; increases blood pressure, heart rate and contractility; inhibits platelet aggregation; stimulates gastric acid secretion; and causes diuresis. Caffeine content is also thought to be responsible for green tea's ability to improve cognitive performance.

Some preliminary studies show that flavonoids found in green tea might reduce lipoprotein oxidation. In vitro tests indicate that catechins in green tea reduce proliferation of vascular smooth muscle that occurs with high concentrations of low-density lipoproteins (LDL). There is some evidence that an unidentified compound in green tea and caffeine suppresses thromboxane formation during blood clotting by inhibiting the release of arachidonic acid from platelets. However, when used in humans green tea does not consistently exhibit useful effects on cardiovascular risk factors.

It is unclear exactly how green tea might reduce the risk of some cancers, but preliminary research suggests EGCG might prevent new blood vessel growth (angiogenesis) in tumors or inhibit tumor cell proliferation, causing cell cycle arrest or apoptosis. Green tea may also reduce oxidative DNA damage, lipid peroxidation and free radical generation, and might reduce mutagenic activity in smokers. Green tea is thought to be beneficial for preventing skin damage and cancer from ultraviolet (UV) radiation due to the antioxidant effects of polyphenols in green tea.

Green tea is also used for weight loss. Early evidence indicates that a green tea extract rich in EGCG can increase calorie and fat metabolism. Research has shown that green tea reduces the risk of developing stomach cancer by 50% and esophageal cancer by 6%

Published Clinical Studies



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