Tea is an integral part of social intercourse in many cultures, and its health benefits have been recognized for hundreds of years. Of the various preparations of tea -- black, oolong, green and white -- green tea has received the most attention for its therapeutic effects. Tea isn't just for drinking, for if you browse the shelves at your favorite cosmetics store, you'll find green tea in many beauty products.
Active Ingredients
Teas contain varying levels of caffeine, theobromine, theophylline, theaflavins, theanine and polyphenols. Most of the health benefits attributed to tea are thought to arise from polyphenols, which are potent antioxidants. Like all tea products, green tea is prepared from the leaves of the Camellia sinensis plant. In contrast to black and oolong teas, green tea leaves are not fermented prior to steaming and drying. This method of processing protects the important polyphenols from degradation and endows green tea with higher antioxidant levels than most other teas. Green tea is 20 to 45 percent polyphenols by weight, and up to 80 percent of those are catechins. Epigallocatechin gallate, or EGCG, is the most abundant catechin in green tea.
Health Benefits
Green tea has been extensively studied for its putative benefits in cardiovascular disease, weight loss, cancer prevention and genital wart treatment. The U.S. Food and Drug Administration has approved a topical ointment, called Veregen, for treating herpes, and the National Cancer Institute is conducting human trials exploring the use of tea for both preventing and treating cancer. However, according to a 2009 article in "American Family Physician," while green tea preparations are a safe alternative for genital wart treatment, the evidence for their use in other conditions is inconsistent and inconclusive.
Skin Protection
According to a 2000 review in "Archives of Dermatology," green tea's polyphenols, when applied topically, could be useful for preventing or treating a variety of skin disorders. Catechins confer protection against inflammatory conditions, such as dermatitis, and cancers caused by chemical or sunlight exposure. Furthermore, a 2007 study in "The Journal of Biological Chemistry" demonstrates that internal use of green tea may also exert beneficial effects on skin. By increasing the production of nitrous oxide in blood vessels, EGCG promotes vascular dilation and improves peripheral circulation.
Considerations
Scientific endorsement of alternative therapies requires a great deal of statistically compelling data. The research supporting green tea's use for an array of health conditions is encouraging, but information is currently insufficient to meet today's standards of evidence-based medicine. However, in the absence of sensitivity to green tea or any of its components, its routine use, both topically and internally, may offer significant health benefits.
References
- "Journal of the American College of Nutrition"; Beneficial Effects of Green Tea -- a Review; Cabrera C, et al.; 2006
- "American Family Physician"; Green Tea: Potential Health Benefits; Schneider C, Segre T; 2009
- "Archives of Dermatology"; Green Tea and Skin; Katiyar S, et al.; 2000
- "The Journal of Biological Chemistry"; Epigallocatechin gallate, a green tea polyphenol, mediates NO-dependent vasodilation using signaling pathways in vascular endothelium requiring reactive oxygen species and Fyn; Kim JA, et al.; 2007
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