what nutritional value does green tea have?
['Catechins. Catechins are a type of polyphenol and are the main astringency component in green tea, long known as tannins. ... ', 'Caffeine. Drinking tea when tired from work or study can make a person feel refreshed. ... ', 'Amino Acid (Theanine) ... ', 'Vitamins. ... ', 'Vitamin B2. ... ', 'Vitamin C. ... ', 'Folic Acid. ... ', 'β-carotene.']