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Green tea quick review
Botanical description: produced from the leaves of the Camellia sinensis, or tea plant. Camellia sinensis is a member of the Theaceae family.
Active constituents:essential oil (aldehydes, phenylethyl alcohols, phenols, hexenal, hexenol, linalool, dihydroactinidiolide and p-vinylphenol), vitamins (B vitamins and ascorbic acid), minerals (fluoride, aluminum), tannins, caffeine, polyphenols.
Health benefits : helps to lower serum cholesterol, prevent oxidation of LDLs, and increase HDL's in the blood; speeds metabolism and enhances weight loss; acts as antioxidants may inhibit the growth of existing cancer cells.

Dosage: recommended consumption is 3 to 4 cups of tea a day, the average cup of green tea contains about 50 to 150 mg polyphenols.
Side effects : large amounts may cause restlessness, nasuea, vomiting, diarrhea or constipation, heart palpitations and headache.
 
Green Tea Extract by Vitabase
Vitabase's Green Tea extract is produced by a European phytopharmaceutical company and is manufactured under strict European quality control standards without the use of harsh solvents. Like all European herbal extracts, the extraction of our green tea extract is regulated to the same high standards as over-the-counter drugs. It is meticulously extracted to provide the optimal level of 50% natural occurring catechins. Click here for more information.
 

Green tea


Green tea is produced from the leaves of the Camellia sinensis, or tea plant. The tea plant, Camellia sinensis, is a member of the Theaceae family. The name sinensis means "Chinese" in Latin. Older names for the tea plant include Thea bohea and Thea viridis. Camellia sinensis is an evergreen shrub or small tree that is usually trimmed to below two metres (six feet) when cultivated for its
leaves. It has a strong taproot. The flowers are yellow-white, 2.5-4 cm in diameter, with 7 to 8 petals. Its fruits are brownish-green containing 1 to 4 spherical or flattened seeds. The seeds can be pressed to yield an oil. The leaves are dark green, alternate and oval, with serrated edges, and the blossoms are white, fragrant, and appear in clusters or singly. Fresh leaves contain about 4% caffeine. The young, light green leaves are preferably harvested for tea production, they have short white hairs on the underside. Older leaves are darker green. Different leaf ages produce differing tea qualities, since their chemical compositions are different. Usually, the tip (bud) and the first two to three leaves are harvested for processing. Tea plants are cultivated in countries where warm, rainy growing conditions are abundant, and are also frequently grown in high altitude areas.

There are three main varieties of tea, including green tea, black tea, and oolong tea. They are all produced from its leaves of camellia sinensis. The difference between the teas is in their processing. Green tea is prepared from unfermented leaves, the leaves of oolong tea are partially fermented, and black tea is fully fermented. Black tea is produced by withering, rolling, fermenting, and then drying the leaves. Oolong tea is semifermented and considered an intermediate product between green and black tea. Unlike black and oolong tea, green tea production does not involve oxidation of young tea leaves. Green tea is dried for a shorter time, and is heated sooner to prevent fermentation. Tea leaves may be left to dry as separate leaves or rolled into small pellets to make gun-powder tea. Because green tea is made from unfermented leaves, it is reputed to contain the highest concentration of polyphenols, chemicals that act as powerful antioxidants. The more the leaves are fermented, the lower the polyphenol content, and the higher the caffeine content. Green tea has the highest polyphenol content while black tea has roughly two to three times the caffeine content of green tea.

 

Active constituents of green tea


Green tea contains essential oil (aldehydes, phenylethyl alcohols, phenols, hexenal, hexenol, linalool, dihydroactinidiolide and p-vinylphenol), vitamins (B vitamins and ascorbic acid), minerals (fluoride, aluminum), tannins, and caffeine, but the primary constituents of interest are the polyphenols. Green tea contains low-molecular-weight polyphenols consisting mainly of flavanol (flavan-3-ol) monomers, which are referred to as catechins. The main catechins in green tea are epicatechin, epicatechin-3-gallate, epigallocatechin, and epigallocatechin-3-gallate (EGCG). Green tea contains roughly 30% to 40% polyphenols. EGCG makes up about 10-50% of the total catechin content. Green tea polyphenols is a class of bioflavanoids, with high antioxidant properties. The catechins have antioxidant activity about 25-100 times more potent than vitamins C and E. Green tea polyphenols also have significant anticarcinogenic, anti-inflammatory, thermogenic, probiotic, and anti-microbial properties. The polyphenols in green tea that act as antioxidants may actually inhibit the growth of existing cancer cells. Green tea polyphenols inhibit the production of arachidonic acid metabolites such as pro-inflammatory prostaglandins and leukotrienes. Green tea also contains alkaloids including caffeine, theobromine, and theophylline. These alkaloids provide green tea's stimulant effects. Green tea contains B vitamins and ascorbic acid, which are destroyed in the process of making black tea. Green tea contains several minerals, including fluoride and aluminum. The fluoride in green tea may be useful in fighting tooth decay. All teas contain caffeine, but green tea contains the lowest amount of caffeine among the three teas.
 

Medicinal uses and health benefits of green tea


Green tea has been consumed for thousands of years in China and other Asian countries. Historical uses of green tea include reducing high blood pressure, inhibiting pathogenic bacteria that cause food poisoning and blocking the actions of carcinogens, ultraviolet light and metastasis. Other traditional uses of green tea include treating flatulence, regulating body temperature and
blood sugar, promoting digestion, and improving mental processes. Green tea's health benefits are largely due to its high content of flavonoids in which catechins are of the main type. Catechins are more powerful than vitamin C and vitamin E in halting oxidative damage to cells and appear to have other disease-fighting properties. Drinking green tea regularly may help to prevent various types of cancer, guard against cardiovascular conditions by lowering cholesterol levels and reducing blood pressure, promote longevity, stave off tooth decay, help heal gum infections, and provide a number of other benefits. Green tea has been shown to speed metabolism and enhance weight loss, increase energy levels and brain power, and even act as a powerful antioxidant. Antioxidants in green tea may prevent and reduce the severity of osteoarthritis.

Consuming green tea has been associated with a reduced risk for several cancers, including skin cancer, breast cancer, lung cancer, colon cancer, esophageal cancer, and bladder cancer. The polyphenols in green tea that act as antioxidants may inhibit the growth of existing cancer cells. Green tea polyphenols, particularly EGCG, may well enhance the body's natural antioxidant system and kill cell-damaging free radicals in the body. Green tea polyphenols exhibits preventative and inhibitory effects against tumor formation and growth. They protect against chemically induced tumor initiation, and metastasis of preexisting tumors. Green tea polyphenols are also antimutagenic, and is effective in reducing the formation of carcinogens in the body and reducing chromosomal damage during mutagen exposure. Green tea polyphenols may be chemopreventative or inhibitory toward lung, skin, and liver cancer, bladder and ovarian tumors, leukemia, and oral leukoplakia.

Green tea has been shown to assist with cardiovascular conditions as it helps to lower serum cholesterol, prevent oxidation of LDLs, and increase HDL's in the blood. Heart diseases are a result of oxidative stress and subsequent generation of free radicals. Green tea polyphenols are potent free radical scavengers due to the hydroxyl groups in their chemical structure. The antioxidant activities of green tea are helpful in lowering cholesterol and preventing hardening of the arteries and ischemic heart disease. Low flavonoid intake has been linked to atherosclerosis, the antioxidant properties of green tea may help prevent atherosclerosis, particularly coronary artery disease.

Green tea has been shown to speed metabolism and enhance weight loss. The green tea catechins have been found to promote thermogenesis. Green tea extract may increase energy levels and promote fat oxidation, and consequently, may be a useful tool in weight control. Green tea polyphenols may inhibit digestive lipases, resulting in decreased lipolysis of triglycerides, which may translate to reduced fat digestion in humans.

Green tea polyphenols have topical antibacterial properties and can help to prevent gingivitis and periodontal disease by killing E. coli and streptococcus bacteria. A regular intake of green tea may reduce the risk of bacteria accumulating in the mouth which can cause tooth decay. The tannin content alone in green tea helps to prevent plaque adhering to teeth. This antibacterial action can also be effective in treating halitosis, or bad breath, by killing odor-causing bacteria. Green tea contains several minerals, including fluoride and aluminum. The fluoride in green tea may be useful in fighting tooth decay.

 

Dosage and administration of green tea


Most green tea products are sold as dried leaf tea. The best way to get the catechins and other flavonoids in tea is to drink it freshly brewed. Decaffeinated, bottled ready-to-drink tea preparations, and instant teas have less of these compounds. Popular Chinese green tea varieties include Longjing (Dragonwell), Mao Jian, Bi Luo Chun, Gunpowder, and Mao Feng. The recommended consumption is 3 to 4 cups of tea a day. The average cup of green tea contains about 50 to 150 mg polyphenols. If you are taking green tea extract, 300 to 400 mg per day of standardized green tea extract is the recommended dosage. To brew green tea, 1 teaspoon (5 grams) of green tea leaves are combined with 1 cup (250 ml) of boiling water, allow tea to steep for three to five minutes to bring out its catechins.
 

Side effects, precautions, interactions


Green tea is generally considered a safe, non-toxic beverage and consumption is usually without side effects. Green tea contains caffeine, large amounts may cause restlessness, nasuea, vomiting, diarrhea or constipation, heart palpitations and headache. Intake of large quantities can lead to constipation or diarrhea. Adding milk to the tea will usually eliminate these side effects by reducing the potency of the tannins. People with heart problems, kidney disorders, stomach ulcers, and psychological disorders (particularly anxiety) should not take green tea. Lactating women should also limit caffeine intake to avoid sleep disorders in infants. Individuals with iron-deficiency anemia who take iron supplements should not drink green tea several hours before and after taking supplements. Green tea also interacts with Doxorubicin and alkaline medications. Precaution is necessary in patients who are taking anticoagulants.