Green tea (Camellia sinensis) was discovered in China in 3000 BC or earlier, and it has many health-promoting effects. Nowadays, scientific evidence indicates that green tea is indeed beneficial to health.
What are the active components of green tea?
-Tea catechins epigallocatechin gallate (EGCG), EGC (epigallocatechin), ECG (epicatechin-3-gallate) és a CG (catekchn-3-gallate) are considered to be associated with the anti-cancer, anti-obesity, anti-atherosclerotic, anti-diabetic, anti-bacterial, anti-viral, and anti-dental caries effects of tea.
-Caffeine stimulates wakefulness, decreases the sensation of fatigue, and has a diuretic effect.
-Theanine and γ-aminobutyric acid act to lower blood pressure and regulate brain and nerve functions.
-Vitamin C is an anti-scorbutic, prevents cataracts, and strengthens the immune system.
What are the main health-promoting efects of green tea?
-anti cancer activity
In a study, EGCG, the major catechins in green tea, inhibited the adhesion of cancer cells to endothelial cell layers. It has been well documented that cancer cells are more susceptible to apoptosis induced by EGCG than normal counterparts. It is suggested that EGCG induces apoptosis selectively in cancer cells.
The first impressive result was reported in 1989 by Oguni, who described that the rate of death from stomach cancer in males of the town of Nakakawane was about one fifth of the average for Japanese males overall and that this low rate might be related to the consumption of green tea. Later, it was reported that tea consumption did not correlate to the risk of stomach cancer. The discrepancy in results may arise from factors such as differences in the type of tea consumed, in cancer etiology, in confounding lifestyle, and in genetic factors. More convincing data for the effects of green tea were presented by Bettuzzi who conducted a clinical trial to assess the safety and efficacy of green tea catechins for the chemoprevention of prostate cancer in individuals with high-grade prostate intraepithelial neoplasias. After 1 year of daily treatment consisting of three capsules containing 200 mg of catechin, only one tumor was diagnosed among the 30 catechin-treated men, whereas 9 cancers were found among the 30 placebo-treated men.
-Daily consumption of green tea has been associated with a lower risk of death from cardiovascular disease, and may be associated with a reduced risk of stroke
-Drinking green tea or taking green tea supplements decreases the blood concentration of total cholesterol (about 7 mg/dL), LDL cholesterol (about 2 mg/dL), and does not affect the concentration of HDL cholesterol
-Daily consumption of green tea is significantly associated with a lower risk of death from any cause
-Green tea may have extensive antibacterial properties (against E.coli, mycobacterium tuberculosis, mycoplasma pneumoniae, spoilage bacteria)
Source: Proc Jpn Acad Ser B Phys Biol Sci. 2012 March 9; 88(3): 88–101., wikipedia, photo: Pixabay