Evergreen shrub clipped to 5 ft (1.5 m) in cultivation, with leathery, dark green leaves and fragrant white flowers.
Habitat & Cultivation
Cultivated principally in India, Sri Lanka, and China, tea has been grown since the earliest times.
Tea contains xanthines, caffeine (1–5%), theobromine, tannins including polyphenols, flavonoids, fats, and vitamin C. Green tea contains significant levels of polyphenols; black tea, which is produced by a process of fermentation, has lower levels.
History & Folklore
In China and Japan many rituals have developed around tea drinking. Significantly it is mostly green tea that is drunk in this way.
Medicinal Actions & Uses
Due to its astringency, tea is useful in digestive infections, helping to tighten up the mucous membranes of the gut and reduce looseness. A strong brew of tea may be used to soothe irritated eyelids, insect stings, swellings, and sunburn, and in an emergency, if nothing better is at hand, tea makes a serviceable treatment for minor burns. In Ayurvedic medicine tea is considered astringent and a nerve tonic.
The caffeine in tea may help to relieve headaches, though less effectively than coffee (Coffea arabica). In light of research, green tea is recognized as being a much healthier drink than black tea.
Green tea’s strong antioxidant activity is due to polyphenols, which give the leaf potential as a cancer preventative. The high intake of green tea in China and Japan is thought to be partly responsible for the low incidence of cancer in these countries.
Clinical trials indicate that green tea may help to promote weight loss and treat hepatitis, and there is the suggestion that it helps to prevent tooth decay. A recent clinical trial indicated that green tea has a genoprotective action, helping to prevent degenerative changes within the body, and potentially slowing the aging process. A 2013 clinical trial found that green tea extract taken by women for 4 months successfully shrank uterine fibroids.