Vitamin Expert

Green Tea

(camilla sinensis)

Botanical family: Theaceae
Parts used: Leaf and bud
Main active constituents: Epigallocatechins, epicatechins, volatile compounds, sterols
Actions: Components act upon various cell messenger and receptor pathways.
Good for: Cardiovascular health, blood glucose control
Available forms: Teas; capsules; tablets; drinks.

Green tea is made from leaves that have undergone minimal oxidation during processing. Green tea originated in China, but has become associated with many cultures throughout Asia. Green tea has recently become relatively widespread in the West where black tea has been traditionally consumed.

History of Green Tea

Green tea consumption has its legendary origins in China dating back more than 4000 years ago, making it the oldest herbal tea known. Green tea was first brewed in 2737BC, during the reign of Emperor Shennong. Green tea has become the raw material for extracts in various beverages, dietary supplements and cosmetic items. Many varieties of green tea have been created in the countries where it is grown. These varieties can differ substantially due to variable growing conditions, horticulture, production, processing, and harvest time.

Current uses of Green Tea


A Cochrane review in 2013 concluded that green tea consumption for 3-6 months appears to lower systolic and diastolic blood pressure by a small amount (about 3mmHg each). Additional analyses examining the effects of long-term green tea consumption on blood pressure have reached similar conclusions. A different Cochrane review performed in 2013 concluded that green tea consumption lowers total and LDL cholesterol concentrations in the blood.


Two meta-analyses concluded that drinking green tea lowers fasting blood sugar .

How to take Green Tea

As a tea infusion several times a day.
As a tablet or capsule according to manufacturer’s recommendation based on their manufacturing method.


There is no evidence that green tea or green tea extracts interact with prescribed drugs if taken at the correct dosage.