• CAM-summaries
  • Alternative medical systems
  • Biologically-based practices
  • Diet & nutrition
    • Breuss cancer cure
    • Carctol
    • Co-enzyme Q10
    • Gerson diet
    • Green tea for prevention
      • What is green tea?
      • How well does green tea work?
      • Is green tea safe?
      • Green tea conclusions
    • Lacto-ovo vegetarian diet
    • Megamin
  • Energy medicine
  • Manipulative & body-based practices
  • Mind-body medicine
• CAM systematic reviews
• CAM and the law
• Prevalence of CAM use

What is green tea?

Green tea is derived from Camellia sinensis, an evergreen shrub of the Theaceae family. Green tea comes from the same plant as black tea but it is produced by a non-fermented process. The medicinal use of green tea dates back to 4,700 years ago in China. The main active ingredients in identified in green tea include polyphenolic compounds such as epicatechin (EC), epicatechin-3-gallate (ECG), epigallocatechin (EGC), and epigallocatechin-3-gallate (EGCG), which are thought to be responsible for their anti-carcinogenic and anti-mutagenic activity. Other polyphenols in green tea include flavanols and their glycosides and depsides such as cholorogenic acid, quinic acids, carotenoids, trigalloylglucose, lignin, protein, chlorophyll, minerals (depending on the soil content, aluminum and manganese), caffeine, and very small amount of methylxanthines.

Human studies on the pharmacokinetics of green tea polyphenols have been conducted. Polyphenols from green tea have been shown to be powerful antioxidants with anticarcinogenic properties. Studies have shown that that ingested polyphenols and their metabolites play some form of role against gastrointestinal cancers. Catechins in green tea are rapidly absorbed and the addition of milk does not impair catechin bioavailability

Tea is the most popular beverage next to water around the world, and green tea accounts for 20% of tea consumption. It is popular in China, Japan, and other South-East Asian countries. Commercial products, or green tea for medicinal use, are provided by tea manufacturers or different pharmaceutical herbal medicine companies. Tea can also be used as a dietary supplements in some countries. The cost of tea is inexpensive.

Green tea can be consumed in the form of a brewed beverage or as capsules containing green tea extract. Currently, there is no established recommended dose for green tea extract. For cancer prevention, studies have examined the effects of habitually drinking from one to ten cups per day, although these findings require confirmation.