Tea is rich in polyphenols that have effects like reducing inflammation and helping to fight cancer.
Green tea is about 30 percent polyphenols by weight, including large amounts of a catechin called EGCG. Catechins are natural antioxidants that help prevent cell damage and provide other benefits.
These substances can reduce the formation of free radicals in the body, protecting cells and molecules from damage. These free radicals are known to play a role in aging and all sorts of diseases.
EGCG (Epigallocatechin Gallate) is one of the most powerful compounds in green tea. It has been studied to treat various diseases and may be one of the main reasons green tea has such powerful medicinal properties (2).
Green tea also has small amounts of minerals that are important for health.
Try to choose a higher quality brand of green tea, because some of the lower quality brands can contain excessive amounts of fluoride (3).
That being said, even if you choose a lower quality brand, the benefits still far outweigh any risk.