The leaf and bud of the Camellia sinensis plant are the basis of both green and black tea. Unlike black tea, which is fermented, green tea is steamed dry immediately after harvesting, which leaves it with larger amounts of polyphenols. Its most effective polyphenol is epigallocatechin gallate (EGCG). Most of the benefits of Green Tea consumption appear to be preventive in nature.
The health benefits of Tea have become well known in recent years. Next to water, tea is the most popular beverage worldwide. Their anti-oxidant, anti-carcinogenic, anti-bacterial and lipid
controlling properties have been the center of many studies over the past several years. Green Tea differs from black tea in that black tea has been through a fermenting process (Oolong varieties are semi-fermented.) While both green and black tea contain similar, complex chemical characteristics, most of the clinical studies have been performed with green tea.
You can buy encapsulated extracts standardized for chemicals called polyphenols. An average dose is 200mg of an extract standardized for 25% polyphenols. You can also buy the dried herb and make tea; it is available in various grades.
Decaffeinated green tea does have the same amount of EGCG as regular green tea. Check your local health food store for decaffeinated green tea capsules. Depending on the brand, one capsule can supply as much EGCG as four cups of tea.
Green Tea is most often used by steeping in hot water, as a supplmement in capsules, or added to food products.
Function; Why it is Recommended
Green Tea has demonstrated superior antioxidant
properties in experimental studies than vitamin C
or E. Green Tea also has the capability to increase the activity of antioxidant enzymes.
The evidence for Green Tea's potent antioxidant effects continues to accumulate. In a recent study researchers found that Green Tea compounds not only directly scavenge free radicals
but also enhance the effectiveness of the body's natural antioxidant systems.
The catechin polyphenol, which works with other chemicals, increases levels of fat oxidation and thermogenesis (where the body burns fuel, such as fat, to create heat). This increase in energy expenditure is probably the mechanism causing weight loss.
Tea contains between 1 and 5% caffeine
as well as other alkaloids. Caffeine is a common central nervous system
stimulant found in coffee at similar or higher levels. Tea also contains flavonoids
such as quercetin
, etc; as well as tannins, fats, amino acids
and nearly 300 other components. Current research into the anticancer polyphenols is sure to keep extracts of Green Tea in the news for years to come.
Studies indicate that green tea may help protect against cancers of the lungs
, skin, liver
and stomach; it also boosts cardiovascular
health and may work as a weight-loss agent by increasing fat metabolism and regulating blood sugar and insulin
levels. Green tea benefits the heart by lowering cholesterol
levels and reducing the tendency of blood platelets
to stick together. It contains numerous cancer-fighting polyphenol compounds, including the antioxidant flavonoid
Green tea extract may promote weight loss, according to an article in the American Journal of Clinical Nutrition [1999; 70: pp.1040-5
]. Green tea extract may also help dieters shed fat. Green tea is a safe alternative to traditional pharmaceuticals because its use is not accompanied by an increase in heart rate.
EGCG inhibits growth as well as the actual initiation of cancer. Green Tea shows special promise against cancer of the esophagus
. Skin care products may contain EGCG.
There are significant results in scientific studies showing that daily Green Tea consumption can prevent high blood pressure. Studies have shown that several cups of Green Tea a day can substantially reduce an individual's risk for heart disease and stroke
Reducing total cholesterol and LDL
, it also increases the levels of positive cholesterol (HDL
Green Tea can strengthen a weak immune system against common illnesses such as the flu, bronchitis
or infections that take a long time to heal or return quickly. It is especially beneficial to chemotherapy
patients who experience declining cell counts.
Oxygen is very important to us, but it can also be a very harmful agent in the form of active or free radical
oxygen. When the active oxygen is combined with fats in our body, it is called lipid peroxide
. As we get older, this lipid peroxide is more easily generated and less easily purged and tends to accumulate in our body, causing more serious diseases and also weakens the skin against infectious changes in cell tissues. Therefore, one way to slow aging may be to prevent the accumulation of active oxygen and lipid peroxide in our body. Antioxidants
in Green Tea are really twenty times stronger than Vitamin E
as confirmed in laboratory tests.
Fluoride in Green Tea stabilizes tooth enamel and the ECGC reduces the development of bacteria
growing in the plaque. Green Tea can also kill other oral bacteria that cause bad breath. Green Tea stimulates the production of saliva
and it will reduce the harmful acids formed in the mouth.
Although there is no epidemiologic data, anecdotal evidence indicates that people in countries where green tea is consumed are far less likely to have rheumatoid arthritis
People who drink Green Tea on a daily basis on average have unusually low rates of heart disease and cancer, and they also live longer.
It is not known exactly how much you need to reap the potential benefits, but four cups a day or more may be required for benefit. Do not add milk if possible, as it reduces the availability of the active flavonoid
Unlike some other antioxidants
, those found in Green Tea cause no toxic side-effects.
The most worrisome chemical in green tea is caffeine
, but this occurs in small amounts (an average of 20 to 30mg per cup, if brewed for two to three minutes). This is much less caffeine than in coffee.