Green, black and oolong are all made from the same plant. The difference is in the way they are processed. Green tea is made from unfermented leaves and contains the highest concentration of powerful antioxidants called polyphenols. Antioxidants scavenge free radicals. Free radicals are compounds that cause damage in the body. Cell alteration, cell death and tampering with DNA are some of the detrimental effects of free radicals. Although free radicals do occur naturally in the body environmental toxins will promote their presence. Air pollution, cigarette smoke, radiation and exposure to ultra-violet rays from the sun are a few environmental factors that increase free radicals. Free radicals are believed to contribute to the aging process as well as a number of other health problems. Antioxidants like polyphenols in green tea can neutralize free radicals and can reduce or prevent some of the damage they cause.

In eastern medicine green tea has been used as a stimulant, diuretic, astringent, to improve heart health, regulating body temperature and blood sugar, promoting digestion, flatulence and improving mental processes.

Health Conditions That May Benefit From Green Tea

Extensive scientific studies have shown that green tea may be useful for many common health ailments. Human, animal and laboratory experiments have resulted in a wide range of potential health benefits to consuming green tea or some form of it.

Studies on green tea and atherosclerosis or specifically coronary heart disease have suggested that the antioxidants in green tea may help prevent its development. However the U.S.D.A. has rejected a petition from tea makers to include a claim on their labels that green tea can help prevent heart disease.

Research has shown that green tea lowers total cholesterol and raises HDL (good) cholesterol in animals and people. Studies have shown that men who drink green tea are more likely to have lower total cholesterol than men who don’t drink green tea. Another study suggested that male smokers who drink green tea have reduced levels of harmful LDL cholesterol than male smokers who don’t drink green tea. One animal study has suggested that polyphenols in green tea may block the intestinal absorption of cholesterol and promote it’s elimination from the body.

Green tea has shown promising results in clinical studies of its effect on cancer. In countries where they consume a large amount of green tea cancer rates tend to be low. While it is not possible to determine if green tea consumption is responsible for these lower rates of cancer, there have been promising results that suggest polyphenols may play a role in preventing cancer. In addition to helping to prevent cancer green tea can have a positive influence on the severity, recovery, remission and survival rate of quite a lot of types of cancer. It is also believe that polyphenols kill cancerous cells. Clinical studies have shown that green tea has various benefits associated with each of the following types of cancers: bladder, breast, ovarian, colorectal, esophageal, lung, pancreatic, prostate, skin and stomach

Green tea has been shown to help reduce inflammation associated with ulcerative colitis and Crohn’s disease, the two types of inflammatory bowel disease or IBD. Should green tea be proven to prevent colon cancer it will be an added benefit to IBD sufferers as they are at a greater risk for colon cancer.

Green tea has long been used to control blood sugar. Green tea may help prevent the development of type I diabetes and slow the progression once it has developed. Green tea may help regulate glucose. For those suffering from borderline diabetes green tea extract powder has been shown to lower the hemoglobin A1c level.

Liver disorders are less likely to develop in men who consume more than ten cups of green tea per day. Green tea has been shown to protect the liver from the damaging effects of toxic substances like alcohol. Green tea has also shown promise for the prevention of liver tumors in mice. Studies suggest that one of the polyphenols found in green tea, catechin, may help treat viral hepatitis. Catechin in very high concentrations was given to people suffering from viral hepatitis, it is not clear if green tea lower in catechin would have the same benefit.

Green tea may boost metabolism and help burn fat. Studies show that a combination of green tea and caffeine improved weight loss and maintenance in overweight and moderately obese people. Researchers suspect that it is the catechin that is responsible for the herb’s fat burning effect.

Others conditions include tooth decay, arthritis, genital warts and symptoms of colds and influenza.

Available Forms

Some commonly available forms of green tea supplements are dried leaves in capsules, standardized extracts and liquid extracts made from leaves and leaf buds. An average cup of green tea contains between 50-150 mg of polyphenols.

Recommended Amounts

For adults the recommended amount is two to three cups of green tea per day. This results in 240-320 mg of polyphenols. If using standardized green tea extract 100-750 mg per day is the recommended dose.

There are no scientific reports on the effects of green tea on children; therefore there are no recommended amounts. Use caution when giving children green tea in any amount.

Precautions

People with heart problems, kidney disorders, stomach ulcers, psychological disorders, pregnancy or breastfeeding should limit their intake of green tea. People who drink excessive amounts of caffeine (including the caffeine in green tea) for extended periods of time may experience insomnia, irritability, heart palpitations and dizziness. Caffeine consumption should be limited if not stopped.

Possible Interactions

If you are taking any of the following medications you should not drink green tea or take green tea extract, powder or capsules without first consulting your doctor. Possible interactions include increased or decreased effects of the medication, negative psychological effects and dangerous changes in blood pressure to name the most common. Here is the list of medications to avoid while using green tea:

Adenosine, antibiotics, beta-lactam, benzodiazepines, beta-blockers, propranolol and metropolis, blood thinning medications (Including Aspirin), chemotherapy, clozapine, ephedrine, lithium, monoamine oxidase inhibitors (MAOIs), oral contraceptives and phenylpropanolamine