Monday, 18 July 2011


Green tea is made from unfermented leaves and reportedly contains the highest concentration of powerful antioxidants called polyphenols. Green tea is believed to have been discovered by the Chinese over four thousand years ago and used for its herbal and medicinal powers. It comes from a plant named Carmellia Sinensis. Green tea has been consumed throughout the ages in India, China, Japan, and Thailand. In traditional Chinese and Indian medicine, practitioners used green tea as a stimulant, diuretic (to promote the excretion of urine), astringent (to control bleeding and help heal wounds), and to improve heart health. Other traditional uses of green tea include treating flatulence (gas), regulating body temperature and blood sugar, promoting digestion, and improving mental processes.

Tea is composed of polyphenols, alkaloids (caffeine, theophylline, and theobromine), amino acids, carbohydrates, proteins, chlorophyll, volatile organic compounds (chemicals that readily produce vapors and contribute to the odor of tea), fluoride, aluminum, minerals, and trace elements. The polyphenols, a large group of plant chemicals that includes the catechins, are thought to be responsible for the health benefits that have traditionally been attributed to tea, especially green tea. The most active and abundant catechin in green tea is epigallocatechin-3-gallate (EGCG). 

There are number of benefits of green tea... one we all know is weight loss...

In 2009, a research paper was published on Effects of catechin enriched green tea on body composition in journal obesity states that regular consumption of green tea - which is rich in naturally-occurring tea actives called catechins - can significantly and positively effect body composition in moderately overweight individuals.The 90-day trial, conducted at Fudan University, in Shanghai, China, and funded by the Lipton Institute of Tea, supports existing evidence that green tea has a significant beneficial effect on body composition in Asian populations.
This new investigation monitored the effects of green tea consumption on body weight, body fat mass, as well as the distribution of fat. 182 moderately overweight Chinese subjects, aged between 18 and 55, were divided into four groups, with each group allocated a regular dose of green tea containing a different quantity of catechins. The results showed that, relative to the control group consuming no green tea catechins, body weight, waist circumference, intra-abdominal fat and the total lean mass all decreased after 90 days in the group that drank the tea with the highest concentration of catechins.

A mechanistic review in 2011 was done on Antiobesity effects of green tea catechins defines that Green tea catechins (GTC) are polyphenolic compounds present in the unfermented dried leaves of the plant, Camellia sinensis. Results from a number of randomized, controlled intervention trials have shown that consumption of GTC (270 mg to 1200 mg/day) may reduce body weight and fat. There are several proposed mechanisms whereby GTC may influence body weight and composition. The predominating hypothesis is that GTC influences sympathetic nervous system (SNS) activity, increasing energy expenditure and promoting the oxidation of fat. Caffeine, naturally present in green tea, also influences SNS activity, and may act synergistically with GTC to increase energy expenditure and fat oxidation. Other potential mechanisms include modifications in appetite, up-regulation of enzymes involved in hepatic fat oxidation, and decreased nutrient absorption.


1. CANCER PREVENTION - Among their many biological activities, the predominant polyphenols in green tea―EGCG, EGC, ECG, and EC― have antioxidant activity. These chemicals, especially EGCG and ECG, have substantial free radical scavenging activity and may protect cells from DNA damage caused by reactive oxygen species. A research done in 2003 states that tea polyphenols inhibit tumor cell proliferation and induce apoptosis . In other laboratory and animal studies done in 2006, tea catechins have been shown to inhibit angiogenesis and tumor cell invasiveness. In addition, tea polyphenols may protect against damage caused by ultraviolet (UV) B radiation, and they may modulate immune system function. Furthermore, green teas have been shown to activate detoxification enzymes, such as glutathione S-transferase and quinone reductase, that may help protect against tumor development. Although many of the potential beneficial effects of tea have been attributed to the strong antioxidant activity of tea polyphenols, the precise mechanism by which tea might help prevent cancer has not been established.

2. LOWERING CHOLESTEROL - Recent findings reveal these green tea can help reduce bad cholesterol (LDL), although only slightly. Re searchers from China, Xin-Xin Zheng and his team of the Peking Union Medical College, Beijing, China conducted a study and poll of the 14 studies on green tea. In each study the researchers randomly divided participants into two groups, ie groups who drank green tea or extract for 3 weeks to 3 months, and the group that received inactive preparations. In general, those from the green tea group had total cholesterol 7.2 mg / dL lower than the comparison group. In addition levels of LDL or bad cholesterol 2.2 mg / dL lower or have decreased more than two percent. While there was no difference in the value of good cholesterol (HDL) in the two groups. The active ingredients are thought to play a role in lowering cholesterol is the catechins which will reduce the absorption of cholesterol in the intestine. Despite having the benefits of cholesterol reduction but experts warn that the effect of the decline is very small. “Drinking green tea can not be recommended for patients who already have high-cholesterol,” says Nathan Wong, researchers say.

3. REDUCE THE RISK OF STROKE - A study published in the journal Stroke in 2009 concluded that an inverse association was found between tea consumption and the risk of ischemic stroke in a southern Chinese population with a significant dose-response relationship for drinking green tea. A meta-analysis published in 2009, analyzing the results from 9 different studies, found an astonishing 21% decrease in stroke risk. This is the result with drinking 3 cups of green tea a day. But adding another 3 cups to the daily intake further lowered down the risk of stroke by another 21%.

4. PREVENTION OF CARDIOVASCULAR DISEASES - Green tea polyphenols have been extensively studied as cardiovascular disease and cancer chemopreventive agents in vitro and in animal studies. However, the effects of green tea consumption in humans remain unclear. However a study done in 2006 called as The Ohsaki Study having an objective to investigate the associations between green tea consumption and all-cause and cause-specific mortality. The Ohsaki National Health Insurance Cohort Study, a population-based, prospective cohort study initiated in 1994 among 40 530 Japanese adults aged 40 to 79 years without history of stroke, coronary heart disease, or cancer at baseline. Participants were followed up for up to 11 years (1995-2005) for all-cause mortality and for up to 7 years (1995-2001) for cause-specific mortality. Results showed that Green tea consumption is associated with reduced mortality due to all causes and due to cardiovascular disease but not with reduced mortality due to cancer.

5. PHYSICAL HEALTH - Antioxidants are what minimise the destruction caused by the normal process of oxidation. Oxidation is like the corrosion of metals due to exposure to the elements, only the damage is to our tissue cells. It's often referred to as oxidative stress. Over time, you can suffer from this damaging process with all sorts of diseases, including heart disease, cancers, and Alzheimer's. Activities such as smoking and alcohol consumption, poor diet, stress and pollutants in the environment all contribute to reducing the body's ability to ward off oxidative damage. It's actually the effort from an overworked immune system to curb or repair cellular and tissue damage from oxidation that creates this damaging stress. This is why anti-oxidants are important. The ingredients found in green tea include four primary polyphenols: epigallocatechin (EGC), epicatechin gallate (ECG), epicatechin (EC), and epigallocatechin gallate (EGCG). These are terms for plant biochemical ingredients that are high in antioxidants.

6. REDUCE STRESS - A 2009 study done in Japan, on the effects of green tea on stress, studied the lifestyles of 42,093 individuals over the age of 40, and assessed their psychological distress based on their lifestyle factors. The research showed that study participants who had an average consumption of five or more cups of green tea per day, had lower psychological distress than participants who drank one or less cups of tea per day.

7. TOOTH LOSS - A study reviewed by Yasushi Koyama, from Tohoku University Graduate School of Medicine (Japan), and colleagues assessed data compiled from 25,078 people, ages 40 to 64 years, who participated in the Ohsaki Cohort 2006 Study. The team determined that those study participants who drank one to two cups of green tea per day reduced their risk of tooth loss by 18%. Five or more cups of green tea daily was associated with a 23% reduction in tooth loss risk. Noting that previous studies have reported that green tea catechins may inhibit the action of oral bacteria linked to development of periodontal disease, the team concludes that: “The present findings indicate an association of green tea consumption with decreased odds for tooth loss.”

8. BRAIN POWER - There are many studies that reported deterioration of brain power is normal as a person ages. It is attributed to failure of brain cells to regenerate. However, a look at 1,003 Japanese who are more than 70 years old in a 2006 study found out that those who drink more green tea showed signs of lesser instances of decrease brain function. The study revealed that those who drink green tea at least six times weekly have a 38% lesser chance of cognitive impairment than those who have only drink green tea three times a week.


Again the most important word is moderation... 2 cups of green tea in a day is fine but not more than that as green tea also have side effects... Several studies have linked liver damage dangers. Green tea can also interact with drugs that reduce efektivtiasnya.

If you are being treated with any of the following medications, you should not drink green tea or take green tea extract without first talking to your health care provider:

Adenosine -- Green tea may inhibit the actions of adenosine, a medication given in the hospital for an irregular (and usually unstable) heart rhythm.

Antibiotics, Beta-lactam -- Green tea may increase the effectiveness of beta-lactam antibiotics by reducing bacterial resistance to treatment.

Benzodiazepines -- Caffeine (including caffeine from green tea) has been shown to reduce the sedative effects of benzodiazepines (medications commonly used to treat anxiety, such as diazepam and lorazepam).

Beta-blockers, Propranolol, and Metoprolol -- Caffeine (including caffeine from green tea) may increase blood pressure in people taking propranolol and metoprolol (medications used to treat high blood pressure and heart disease).

Blood Thinning Medications (Including Aspirin) -- People who take warfarin, a blood thinning medication, should not drink green tea. Since green tea contains vitamin K, it can make warfarin ineffective. Meanwhile, you should not mix green tea and aspirin because they both prevent platelets from clotting. Using the two together may increase your risk of bleeding.

Chemotherapy -- The combination of green tea and chemotherapy medications, specifically doxorubicin and tamoxifen, increased the effectiveness of these medications in laboratory tests. However, these results have not yet been demonstrated in studies on people. On the other hand, there have been reports of both green and black tea extracts stimulating a gene in prostate cancer cells that may cause them to be less sensitive to chemotherapy drugs. Given this potential interaction, people should not drink black and green tea (as well as extracts of these teas) while receiving chemotherapy for prostate cancer in particular.

Clozapine -- The antipsychotic effects of the medication clozapine may be reduced if taken fewer than 40 minutes after drinking green tea.

Ephedrine -- When taken together with ephedrine, green tea may cause agitation, tremors, insomnia, and weight loss.

Lithium -- Green tea has been shown to reduce blood levels of lithium (a medication used to treat manic/depression).

Monoamine Oxidase Inhibitors (MAOIs) -- Green tea may cause a severe increase in blood pressure (called a "hypertensive crisis") when taken together with MAOIs, which are used to treat depression. Examples of MAOIs include phenelzine and tranylcypromine.

Oral Contraceptives -- Oral contraceptives can prolong the amount of time caffeine stays in the body and may increase its stimulating effects.

Phenylpropanolamine -- A combination of caffeine (including caffeine from green tea) and phenylpropanolamine (an ingredient used in many over-the-counter and prescription cough and cold medications and weight loss products) can cause mania and a severe increase in blood pressure. The FDA issued a public health advisory in November 2000 to warn people of the risk of bleeding in the brain from use of this medication and has strongly urged all manufacturers of this drug to remove it from the market.

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