Green tea supplements come from the tea plant Camellia sinensis. Traditionally, green tea has been consumed in China, India, Japan and Thailand as a stimulant, diuretic, astringent and to promote cardiovascular health. Recently, green tea supplements have also been advocated for treating chronic illnesses, such as diabetes and cancer. Green tea supplements are available in the forms of herbal teas, extracts, tablets and capsules.
Camellia sinensis is a large, hardy shrub with evergreen leaves, which reaches more than 6 feet in height. It is indigenous to China, India, Thailand and Japan and extensively cultivated in those countries. For example, China alone produces about 300 different varieties of Camellia sinensis. The leaves are 4 to 15 cm long and 2 to 5 cm broad with small delicate leaf structures. Normally, the bud and first two to three leaves are picked for processing.
Green Tea Supplements Composition
Green tea extracts contain the highest concentration of polyphenol compounds, chemicals with free-radical scavenging properties. Epigallocatechin gallate, or EGCG, is the most robust polyphenol in green tea, which accounts for approximately 40 percent of the total polyphenol content of green tea extracts. Green tea supplements also contain volatile oils, alkaloids, caffeine, tannins, polysaccharides, vitamins and minerals.
Green Tea Health Benefits
Green tea supplements have been shown to protect against cancer or slow its progression once it has developed. The anti-tumor effects of green tea are largely attributed to the potent antioxidant effects of green tea polyphenols, according to the Pennington Biomedical Research Center. Green tea supplements are also used to control blood glucose in patients with type 1 diabetes. They can lower the levels of sugar in the blood by improving insulin secretion. Supplementing with green tea products also helps prevent high blood pressure, stroke and heart attacks.
Green tea supplements are typically safe, even in larger amounts; however, you must take products made from green tea with care, under the supervision of your doctor, because green may produce side effects like everything else. Women must avoid taking green tea supplements during pregnancy and lactation, because green tea caffeine can pass into breast milk and cause sleep-related problems in nursing infants. Green tea can stimulate the production of excessive stomach acid, so patients with sensitive stomachs must limit their green tea intake to avoid adverse effects, such as heart burn, diarrhea and a reduction in appetite.