Green tea is high in polyphenols, especially flavonoids and phenolic acid. The reason polyphenols are good for you is they help reduce cancer, diabetes, cardiovascular and neurogenerative diseases. Polyphenols are antioxidants that repair free radical damage and also reduces Type 2 diabetes, inflammation, obesity, and heart disease. This is a well-researched article that I got from the Specialty Tea Institute. The article also goes into other foods that are high in polyphenols too.