Green Tea is well-established as a potent source of healing antioxidants called polyphenols, the same beneficial compounds found in fruits and vegetables and even in red wine. The leaf also boasts the presence of a superstar antioxidant called EGCG (epigallocatechin-gallate) as well as other notable healing substances including fluoride, catechins, and tannins.
Tannins are thought to help the body discharge toxins due to pollution and to accelerate the metabolism of fats.
Vitamins and minerals
Chemical analysis has revealed that green tea contains significant amounts of water-soluble vitamins and minerals, particularly zinc, manganese, potassium, niacin, folic acid and vitamin C. In fact, one cup of green tea has more vitamin C than an orange. Researchers at the University of Kansas attributed green tea with 100 times the antioxidant strength of vitamin C, and 25 times that of vitamin E. A United States Department of Agriculture study found that the antioxidant capacity of green tea is better than twenty-two various fruits and vegetables.
It aids in treating high cholesterol, high triglycerides, hypertension, and stimulates immune functions. Green tea may actually lower the risks for arteriosclerosis. Research has shown that it guards against cardiovascular disease by lowering cholesterol levels, improving the ratio of LDL cholesterol to HDL cholesterol, reduces platelet aggregation (clumping or clotting of blood cells), and lowers blood pressure.
Combats fatigue and plaque
This herb eases mental fatigue and has been used in treating digestive tract infections. The Chinese often use it to treat migraine headaches. It can also help to prevent plaque buildup on the teeth, and since the leaves contain a natural fluoride, may be helpful in preventing tooth decay. Many of the medicinal claims made for green tea haven't been examined outside a laboratory setting, specifically in clinical trials that assess the plant's health effects in people. On the other hand, the pure research findings are exciting and there certainly appears to be no harm in integrating this extract into your daily diet.
Although the evidence for humans is not yet conclusive, green tea may help to:
The American Journal of Clinical Nutrition conducted astudy in 1999 in which it was found that green tea extract significantly increased energy expenditure (a measure of metabolism), and fat oxidation in men who took a green tea extract as opposed to a placebo or caffeine alone.. The researchers felt that this study had wonderful implications for weight control. The study indicated a nearly 40% increase in daytime thermogenesis. In other words, dieters would burn 40% more fat during the day with Green Tea Extract. It can also help to regulate blood sugar and insulin levels.
The antioxidant EGCG sets in motion a process called apoptosis. Interestingly, the cell death that ensues only affects cancer cells, not healthy ones. EGCG may well enhance the body's natural antioxidant system as well, encouraging the elimination of damaging oxygen molecules called free radicals.
Hasan Mukhtar, Ph.D., professor at Case Western Reserve University and a prominent researcher in this area, believes there is
"a strong indication that green tea is protective for prostate as well as esophageal and stomach cancers."
Green tea and reduced cancer risk
In a large-scale study of more than 35,000 post-menopausal Iowa women (American Journal of Epidemiology, 7/96), those who drank two or more cups of tea daily were less likely to develop cancers of the urinary or digestive tract.
One large-scale study in China found that people who drank as little as one cup of green tea a week for six months had a reduced risk of developing certain kinds of cancers (rectal, pancreatic, and others) than did people who drank green tea less frequently or not at all. Other preliminary research indicates that green tea can help to combat breast, stomach, and skin cancer.
Scientists have even discovered that applying green tea to the skin can help cure and prevent some forms of skin cancer and other skin disorders, protect the skin from both long-term and short-term damage from the sun's ultraviolet rays and act as an antibacterial agent when applied to skin infections.
Evidence from the Nurses' Health Study suggests that green tea beverage consumption is associated with a lower incidence of breast cancer, lung cancer, and cancers of the gastrointestinal tract. In a physiologic study, green tea beverages drunk with meals inhibited the development of nitrosomines (carcinogenic compounds) in human volunteers.
Japanese men, who commonly drink four to six cups of green tea daily, have a significantly lower mortality rate from prostate cancer than Westerners. And the incidence of prostate cancer in China, whose population consumes green tea regularly, is the lowest in the world. Evidence from a growing number of animal and lab studies suggests that green tea may be protecting these men against prostate cancer. A Mayo Clinic study this past year found that the main polyphenol in green tea, called EGCG, inhibits the growth of prostate cancer cells and in high concentrations destroys them. Scientists at Case Western Reserve University in Cleveland reported recently that green tea polyphenols inhibit an enzyme that is over-expressed in prostate cancer, indicating that green tea might be effective in prostate cancer prevention. And a preliminary study by Japanese researchers at Kobe University showed that mice fed a green tea extract and then injected with a substance that causes prostate cancer were less likely to grow tumors than control animals.
Antioxidants in green tea may prevent and reduce the severity of osteoarthritis. Studies have shown that if you consume approximately four cups of green tea a day you may be able to protect yourself from developing arthritis, and if you already have arthritis, consuming green tea can help to diminish the inflammation it causes.
In an animal study published in the Proceedings of the National Academy of Sciences in 1999, researchers found that polyphenols, the antioxidants found in green tea, reduced the likelihood of developing a type of arthritis similar to human rheumatoid arthritis. Not only was the polyphenol group less likely to develop arthritis but, in those who did develop the condition, the disease occurred later and was milder than that which occurred in the water-drinking group. Of 18 animals drinking polyphenols, only eight developed arthritis, compared with 17 of 18 mice in the control group. According to the investigators: "Based on our data, it is tempting to suggest that green tea in general, and the polyphenols present therein in particular, may prove to be a useful supplement/addition with other agents for the treatment of arthritis."