Green tea has in common with black tea the plant from which it is obtained, Camellia sinensis. But the similarities end here. In fact, the different production process leads the two teas to have different properties and makes green tea a real health elixir, with anti-inflammatory and antioxidant properties, useful to keep blood pressure, blood sugar and body weight under control, able to support both mood and brain function. But green tea seems also to have an anticancer action, as proven by a review published a few weeks ago in the International Journal of Molecular Sciences by a team of the University of Gdansk, Poland.
Green tea does not undergo the fermentation process as it happens with black tea. And this is precisely what determines, in green tea, a higher quantity of catechins, which are powerful antioxidants. The action of the catechins is aimed at counteracting free radical damage and cellular degeneration. In fact, free radicals are considered essential in the initial phase and subsequent development of tumors (Rios Arrabal et al, Springerplus, 2013). Catechins fight to the action of free radicals through various effects, all proven, such as the inhibition of cell division and the induction of antioxidant enzymes. In addition to this, it has been shown that drinking 4 cups of green tea every day for 4 months has led to a reduction in the body of 8-hydroxydeoxyguanosine, which is an indicator of DNA damage caused by free radicals. Green tea is considered a valuable ally in the fight against different types of tumors such as prostate, pancreas, breast and stomach. Green tea, thanks to its anti-tumor action, is certainly an excellent choice for prevention and to bring benefit to the lifestyle, but does not replace the therapy indicated by the doctor.
The types of green tea with the highest content in catechins are generally the Japanese ones, examples are Sencha tea, Gyokuro, matcha. The infusion time also determines the amount of catechins. Between 60 and 70° C, the best temperature for infusing green tea leaves, it is recommended to leave the tea to brew for at least 8-10 minutes (Beliveau and Gingras, The anti-cancer diet). Finally, another recommendation. It is always better to prefer green tea taken as an infusion and not as a supplement. In fact, a few years ago the European Food Safety Authority, EFSA, indicated in a report that supplements, due to the very high content in catechins, could cause liver damage in the long run. This effect is not attributable instead to the infusion of green tea, considered by EFSA to be absolutely safe because the amount of catechins is lower and inserted in a synergy of beneficial substances (Younes et al, EFSA Journal, 2018).