Green tea information, FAQ and product listing page. This page contains everything you need to know about green tea.
Quick jump to the sub-sections on this page:
There are three main types of tea, including green, black and oolong. The differences between the teas are derived from their processing. Green tea is made from leaves that are unfermented and are said to contain the highest concentration of antioxidants, known as polyphones. The antioxidants in our body protect us, they are substances that destroy free radicals, dangerous compounds that enter the body and can cause harm. Free radicals consist of the sun, radiation, cigarette smoke, air pollution, etc. Antioxidants like polyphenols located in green tea are said to neutralize the free radicals in our bodies, reducing and possibly preventing damage they cause.
Archaeological evidence from 500,000 years ago suggests that people have been consuming tea leaves steeped in boiling water for that many years, perhaps longer. The first countries to cultivate tea are Indian and China. Fast forward to today, where hundreds of millions of people around the world consume green tea (Camellia sinesis). Its widespread popularity is attributed to the many health benefits that the people who drink it experience.
The Chinese and Indian cultures used green tea as primarily a stimulant, diuretic (helps promote the excretion of urine), astringent (controls bleeding and heals wounds), and to improve the health condition of one’s heart. Some other traditional uses of green include the treatment of flatulence, regulating body temperature, promoting digesting, and increasing mental acuity.
Many studies have been conducted into the heath effects of green tea. These studies have found green tea be useful in the following health conditions:
- Breast cancer
- Colorectal cancer
- Crohn's disease
- Lung cancer
- Prostate cancer
- Skin cancer
- Ulcerative colitis
The power behind green tea lies in the fact that it contains a plentiful supply of catechin polyphenols, specifically epigallocatechin gallate (EGCG). EGCG is an extremely powerful anti-oxidant – in addition to inhibiting the growth of cancer cells, it can kill cancer cells that do form without harming healthy tissue. EGCG has also been effective in lowering LDL cholesterol levels and inhibiting the formation of abnormal blood clots. Considering that the formation of abnormal blood clots are the leading cause of heart attacks and stroke, green tea should be used by anybody who has an elevated risk of these health conditions.
The majority of green tea products on the market are sold as dried leaf tea. Extracts also exist, originating from the leaves and leaf buds. On average, a cup of green tea will contain approximately 50 to 150 mg of polyphenols. Green tea products that come decaffeinated contain polyphenols that are concentrated. In addition, capsules and the increasingly popular liquid forms are available in supermarkets and gas stations around the United States and the world.
There have not been any scientific studies pertaining to the pediatric use of green tea amongst youth, therefore it is not currently recommended for children.
Depending on the brand of green tea, a few cups of green tea containing about 240-320 mg of polyphenols or 300-400 mg per day of the standard green tea extract is the recommended dosage.
While herbs are considered to be the most natural approach at improving our bodies, they do contain active substances that could possibly trigger side effects. Herbs found in green tea can interact with other medications, supplements, or even other herbs. Because of this, those that are using green tea should take them with caution, under the guidance of a medical professional.
Individuals that have experienced heart problems, stomach ulcers, psychological disorders, or kidney disorders should not use green tea. Additionally, those that are pregnant or are breastfeeding should not consider taking green tea.
Those that drink an extraordinary amount of caffeine for a long period of time can experience the same symptoms those that drink coffee or soda in high doses will. These include irritability, heart palpitation, dizziness, diarrhea, headaches, loss of appetite, and nausea. A serious sign of caffeine toxicity (caffeine poisoning) are vomiting and/or abdominal spasms. If this is the case, you should seek the assistance of a medical professional.
Sources Used:Blumenthal M, ed. The Complete German Commission E Monographs. Therapeutic Guide to Herbal Medicines . Boston, Mass: Integrative Medicine Communications; 1998:47, 132. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications; 1998:126-129. Ernst E, ed. The Desktop Guide to Complementary and Alternative Medicine: An Evidence-Based Approach . Mosby, Edinburgh; 2001:119-121.Setiawan VW, Zhang ZF, Yu GP, et al. Protective effect of green tea on the risks of chronic gastritis and stomach cancer. Int J Cancer . 2001;92(4):600-604.Taylor JR, Wilt VM. Probable antagonism of warfarin by green tea. Ann Pharmacother. 1999;33(4):426 – 428.Weisburger JH. Tea and health: a historic perspective. Cancer Letters . 1997;114:315-317.Yamane T, Nakatani H, Kikuoka N, et al. Inhibitory effects and toxicity of green tea polyphenols for gastrointestinal carcinogenesis. Cancer . 1996;77(8 Suppl):1662-1667.