Green tea is second only to water as the most consumed beverage in the world. It has been used medicinally for centuries in India and China. Green tea is prepared by picking, lightly steaming and allowing the leaves to dry whereas black tea is fermented before drying. Fermentation can destroy some of the active components of black tea. The active constituents in green tea are powerful antioxidants called polyphenols (catechins) and flavonols. Tannins in tea are large polyphenol molecules and form the bulk of the active compounds in green tea, while catechins make up nearly 90% of the tannins. Several catechins are present in significant quantities and account for the bulk of research: epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate EGCG. EGCG accounts for 10-50% of the total catechin content and appears to be the most powerful of the catechins; its antioxidant activity about 25-100 times more potent than vitamins C and E. One cup of green tea may provide 10-40mg of polyphenols and has antioxidant activity greater than a serving of broccoli, spinach, carrots or strawberries. Research shows that green tea may have be anti-atherogenic by reducing cholesterol & triglycerides; reduce blood clotting; enhance immune function; enhance weight loss; and be anti-cancenogenic.

Theoretically, the high antioxidant activity of green tea makes it beneficial by protecting the body from oxidative damage due to free radicals. Diseases that are association with free radical damage include cancer, heart disease, suppressed immune function, and accelerated aging.

In the laboratory, green tea is an effective antioxidant. It can protect against experimentally induced DNA damage; and slow or halt the initiation and progression of cancerous tumor growth. There is also evidence from some studies that green tea provides significant immunoprotective qualities, particularly in the case of cancer patients undergoing radiation or chemotherapy. White blood cell count appears to be maintained more effectively in cancer patients consuming green tea compared to non-supplemented patients

There may also be an anti-obesity action of green tea. In one study, mice receiving green tea in their diets had a significant suppression of food intake, body weight gain and fat tissue accumulation. Also, levels of cholesterol and triglycerides were lower in mice receiving the green tea diet and leptin levels in serum showed a decrease with green tea treatments – indicating that green tea may have a direct effect reducing body weight.

Dosage: Typical dosage recommendations are for 125-500mg/day – preferably of an extract standardized to at least 60% polyphenols and/or EGCG as a marker compound (this should be equivalent to 4-10 cups of brewed green tea).

Side Effects: Green tea consumption of as much as 20 cups per day has not been associated with any significant side effects. In high doses, teas that contain caffeine may lead to restlessness, insomnia, and tachycardia. Decaffeinated versions of green tea and green tea extracts are available – but the amounts of phenolic/catechin compounds can vary between extracts.

(Source: www.supplementwatch.com)

Research Overview

Green Tea:
1. Prevents tumor growth and metastasis
2. May be used to control H pylori gastric disease
3. May be an effective therapy in treating human papilloma virus (HPV) cervical lesions
4. Protects normal cells from the radiation of cancer cells
5. Is a powerful antioxidant
6. May be used as an anti-inflammatory for the skin
7. Reduces risk of breast cancer
8. Reduces risk of lung cancer
9. Reduces risk of cancer in alcohol drinkers
10. Reduces risk of cancer in cigarette smokers
11. Reduces the risk of cancer from proximity to PCP pollutants
12. Used in treatment for cervical cancer
13. Protects prostate from tumor development
14. Protects bladder from tumor development
15. Protects from gastric atrophy during fasting
16. Diminishes lipid peroxidation in the brain
17. May be used to treat skin tumors
18. Control growth of myelogenic leukemia cells
19. May prevent atherosclerosis
20. Is a free radical scavenger
21. May prevent Parkinson’s disease
22. May be used to treat periodontal disease
23. Halts development of breast cancer tumors
24. May help prevent cataracts
25. May be effective in treating neurodegenerative diseases
26. Is beneficial in the treatment of diabetes
27. May prevent liver damage from alcohol
28. May prevent cancer of the mouth
29. Reduces inflammation in arthritis
30. Lowers total cholesterol levels
31. Prevents ishemic cardiac damage
32. May prevent Alzheimer's disease
33. May be used to treat baldness
34. May control obesity
35. Reduces risk of colon cancer

Green Tea Abstracts (292)