History

There is archaeological evidence that suggests that tea has been consumed for almost 5000 years, with India and China being two of the first countries to cultivate it. Green tea has been used as traditional medicine in areas such as India, China, Japan and Thailand to help everything from controlling bleeding and helping heal wounds to regulating body temperature, blood sugar and promoting digestion.
The Kissa Yojoki (Book of Tea), written by Zen priest Eisai in 1191, describes how drinking green tea can have a positive effect on the five vital organs, especially the heart. The book discusses tea’s medicinal qualities, which include easing the effects of alcohol, acting as a stimulant, curing blotchiness, quenching thirst, eliminating indigestion, curing beriberi disease, preventing fatigue, and improving urinary and brain function. Part One also explains the shapes of tea plants, tea flowers, and tea leaves, and covers how to grow tea plants and process tea leaves. In Part Two, the book discusses the specific dosage and method required for individual physical ailments.
The Chinese have known about the medicinal benefits of green tea since ancient times, using it to treat everything from headaches to depression. Today, scientific research in both Asia and the west is providing hard evidence for the health benefits long associated with drinking green tea.
Here are just a few medical conditions in which drinking green tea is reputed to be helpful:

  • cancer
  • rheumatoid arthritis
  • high cholesterol levels
  • cardiovascular disease
  • infection
  • impaired immune function

What makes green tea so special?

The secret of green tea lies in the fact it is rich in catechin polyphenols, particularly epigallocatechin gallate (EGCG). EGCG is a powerful anti-oxidant: besides inhibiting the growth of cancer cells, it kills cancer cells without harming healthy tissue. It has also been effective in lowering LDL cholesterol levels, and inhibiting the abnormal formation of blood clots. The latter takes on added importance when you consider that thrombosis (the formation of abnormal blood clots) is the leading cause of heart attacks and stroke.
Why don’t other Chinese teas have similar health-giving properties? Green, oolong, and black teas all come from the leaves of the Camellia sinensis plant. What sets green tea apart is the way it is processed. Green tea leaves are steamed, which prevents the EGCG compound from being oxidized. By contrast, black and oolong tea leaves are made from fermented leaves, which results in the EGCG being converted into other compounds that are not nearly as effective in preventing and fighting various diseases. Green tea can even help prevent tooth decay! Just as its bacteria-destroying abilities can help prevent food poisoning, it can also kill the bacteria that causes dental plaque. Meanwhile, skin preparations containing green tea – from deodorants to creams – are starting to appear on the market.

Green tea is popular in China, Korea, Uzbekistan, Kyrgyzstan, Kazakhstan, Japan, Pakistan, Taiwan, Hong Kong, Morocco, and the Middle East. Recently, it has become more widespread in the West, where traditionally black tea is consumed.

Cultivation

Camellia sinensis is an evergreen shrub grown in part shade to full shade. Most are hardy from zone 6B to zone 7B. You can grow a Tea plant easily in a greenhouse or on a porch even if you have bring it in during the winter.

Most Tea varieties tolerate temperatures down to 20 degrees F. Tea prefers a wet humid summer and a cool, dry winter with no soil freezes.

What’s In Green Tea That Makes It Healthy?

Researchers have successfully isolated the active ingredients of green tea, including catechin, theanine and saponin. Discover what vitamins, amino acids and other nutrients and active ingredients exist in green tea. Learn their health benefits and what they contribute to the taste and aroma of green tea. Learn what counteracts the effects of caffeine in green tea?

Green Tea’s Antioxidant Properties

Catechin works to scavenge active oxygen species in the blood. These species are beneficial because they help protect the body from harmful microorganism.

Green Tea Diet & Weight Loss

This section provides some of the latest green tea weight loss research. There are studies on: green tea consumption & body fat reduction, green tea’s increase of metabolism, Dr. Sanjay Gupta on the benefits of tea, and a green tea derivative causing weight loss.

Green Tea & Cancer

Epidemiological observations have shown that people in green-tea consuming countries-mainly Japan and China-have very low rates of cancer. In Japan, the women who teach the tea ceremony, drinking more than average amounts of extra-strong green tea, are noted for a low mortality rate and longevity; deaths from cancer are especially rare.

White Tea Health Information

White teas are very rare and seldom found outside of China. They are made from buds and young leaves, which are steamed or fired to inactivate polyphenol oxidase, and then dried. Thus, white tea retains the high concentrations of catechins present in fresh tea leaves. Green tea is made from more mature tea leaves than white tea, and may be withered prior to steaming or firing.
White tea is the produced chiefly from tea leaf buds. Because it is minimally processed, it may exhibit potent disease-fighting potential. To date, however, there is comparatively little research on its health effects.
To make green tea, the leaves are picked and preserved (usually by steaming or baking) to keep them from undergoing the process of fermentation (or oxidation).
To make oolong and black tea, the leaves are picked and exposed to the air for a period of time. During this period, the leaves ferment. Oolong tea is exposed to the sun and allowed to partially ferment; black tea is fermented completely.
The process of fermentation slightlychanges the essential chemical makeup of tea. The longer the leaves are allowed to ferment, the weaker the tea’s natural roster of cancer-fighting compounds becomes, while the caffeine content of the tea leaves steadily increases.
Generally, green tea has one-half to one-third thecaffeine of black tea.
Green tea contains several substances collectively called polyphenols that have displayed potent antioxidant effects and other cancer-combating properties. Approximately 90 percent of the polyphenols found in green tea are called catechins (KAT-uh-kins). Green tea contains approximately three times the quantity of catechins found in black tea. The chief catechins found in green tea are:

  • catechin
  • gallocatechin
  • epicatechin
  • epigallocatechin
  • epicatechin gallate
  • epigallocatechin gallate (also known as EGCG).

EGCG is the most active component in green tea, and is a stronger antioxidant than either vitamin C or E. For this reason, it is the most widely studied green tea compound.

How to Take It

Pediatric

There are no known scientific reports on the pediatric use of green tea, so it is not currently recommended for children.

Adult

Depending on the brand, two to three cups of green tea per day (for a total of 240 to 320 mg polyphenols) or 300 to 400 mg per day of standardized green tea extract is the recommended dosage.

Precautions

The use of herbs is a time-honored approach to strengthening the body and treating disease. However, herbs contain active substances that can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, people should take herbs with care, under the supervision of a practitioner knowledgeable in the field of botanical medicine.
People with heart problems, kidney disorders, stomach ulcers, and psychological disorders (particularly anxiety) should not take green tea. Pregnant and breastfeeding women should also avoid green tea.
People who drink excessive amounts of caffeine (including caffeine from green tea) for prolonged periods of time may experience irritability, insomnia, heart palpitation, and dizziness. Caffeine overdose can cause nausea, vomiting, diarrhea, headaches, and loss of appetite. If you are drinking a lot of tea and start to vomit or have abdominal spasms, you may have caffeine poisoning. Lower your caffeine intake and see your healthcare provider if your symptoms are severe.

“TEA is Dew of Heaven” – Lu-Yu said in 780 A.D. A Chinese King -Tang Xuan Zong in Tang Dynasty (618 – 907 A.D.) asked a monk more than 130 years old: How could you live so long? Did you take any medicine for that? The monk answered: Just drank tea daily, nothing else.

Sources: University of Maryland – Medical Center, Wikipedia, Green Tea Benefit

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