Scientists have also discovered that the antioxidants flavonoids may also protect the brain from oxidative stress. The scientists extrapolated that a human would need to drink about three liters of liquid infused with 0.5 percent of the catechins to get similar effects. However, because humans ingest other antioxidants in the form of vitamins and plant polyphenols, it’s likely that a much lower quantity could be effective in protecting memory.
• One Chinese study found that men who drank more than three cups of tea a day reduced their risk of prostate cancer by 70 percent. In another study funded by the National Institute of Health, 79 men with prostate cancer were told to either drink 6 cups of green tea a day or 6 cups of water. After 3 to 8 weeks, the levels of prostate-specific antigen, a protein that may indicate cancer, were lower in the men who drank green tea than those who drank water. An indicator of inflammation, nuclear factor-kappaB, linked to cancer growth, was also lower in the men who drank the green tea.
Certain studies indicate that intake of flavan-3-ols and/or anthocyanidins found in green tea may improve glycemic control and help normalize blood sugar levels. Due to its anti-inflammatory properties, green tea is believed to be beneficial for those who are at-risk or diagnosed with type 2 diabetes. Green tea’s catechins, especially EGCG, appear to have anti-obesity and antidiabetic effects.

Grown under shade for three weeks prior to plucking, gyokuro is one of the most exclusive varieties of tea produced in Japan.[60] The shading technique imparts a sweeter flavor, and produces a particularly rich color thanks to the higher amounts of chlorophyll in the shaded leaf. Gyokuro tea is associated with the Uji region, the first tea-growing region in Japan. It is often made using smaller-leaf cultivars of the tea plant.[61]