Health Benefits of Green Tea

Green tea is made from unfermented leaves and reportedly contains the highest concentration of powerful antioxidants called polyphenols. Antioxidants are substances that scavenge free radicals -- damaging compounds in the body that alter cells, tamper with DNA (genetic material), and even cause cell death.  Free radicals occur naturally in the body, but environmental toxins (including ultraviolet rays from the sun, radiation, cigarette smoke, and air pollution) also give rise to these damaging particles.  Scientists believe that free radicals contribute to the aging process as well as the development of a number of health problems including cancer and heart disease.  Antioxidants such as polyphenols in green tea can neutralize free radicals and may reduce or even help prevent some of the damage they cause. http://www.umm.edu/altmed/articles/green-tea-000255.htm

High Cholesterol and Green Tea Health Benefits

Research shows that green tea lowers total cholesterol and raises HDL ("good") cholesterol in both animals and people.  One population-based study found that men who drink green tea are more likely to have lower total cholesterol than those who do not drink green tea.  Results from one animal study suggest that polyphenols in green tea may block the intestinal absorption of cholesterol and promote its excretion from the body.  In another small study of male smokers, researchers found that green tea significantly reduced blood levels of harmful LDL cholesterol.  http://www.umm.edu/altmed/articles/green-tea-000255.htm

Cancer and Green tea Health Benefit

In scientific literature, epidemiologic studies have linked reduced rates of certain cancers to cultures in Asia where green tea is a popular drink and the health benefits of green tea are well known.  A chemical in green tea had been reported to have anticarcinogenic functions.  Green tea, unlike black tea, is not subjected to high temperatures in the drying process.  As a result, it contains much more abundant levels of a polyphenol called epigallocatechin 3-gallate (EGCG) than are found in black tea. EGCG had been found to inhibit experimental tumor growth in animals. http://discoverysedge.mayo.edu/green_tea/index.cfm

Bladder Cancer and Green Tea Health Benefits

Only a few studies have examined the relationship between bladder cancer and green tea consumption.  In one study that compared people with and without bladder cancer, researchers found that women who drank black tea and green tea were less likely to develop bladder cancer.  A follow-up study by the same group of researchers revealed that bladder cancer patients (particularly men) who drank green tea had a substantially better 5-year survival rate than those who did not, clearly demonstrating the health benefits of drinking green tea. http://www.umm.edu/altmed/articles/green-tea-000255.html

Breast Cancer and Green Tea Health Benefit

Studies to investigate the health benefits of green tea suggest that polyphenols in green tea inhibit the growth of breast cancer cells.  In one study of 472 women with various stages of breast cancer, researchers found that women who consumed the most green tea experienced the least spread of cancer (particularly premenopausal women in the early stages of breast cancer).  They also found that women with early stages of the disease who drank at least 5 cups of tea every day before being diagnosed with cancer were less likely to suffer recurrences of the disease after completion of treatment.  Due to this study alone, all women should drink green tea every day. http://www.umm.edu/altmed/articles/green-tea-000255.html

Ovarian Cancer and Green Tea Health Benefits

In a study conducted on ovarian cancer patients in China and green tea health benefits, researchers found that women who drank at least one cup of green tea per day survived longer with the disease than those who didn’t drink green tea.  In fact, those who drank the most green tea, lived the longest. http://www.umm.edu/altmed/articles/green-tea-000255.html

Pancreatic Cancer and Green Tea Health Benefit

In one large-scale study researchers compared green tea drinkers with non-drinkers and found that those who drank the most tea were significantly less likely to develop pancreatic cancer.  This was particularly true for women -- those who drank the most green tea were half as likely to develop pancreatic cancer as those who drank less tea.  Men who drank the most tea were 37% less likely to develop pancreatic cancer.  Further studies in animals and people are needed before researchers can recommend green tea for the prevention of pancreatic cancer. http://www.umm.edu/altmed/articles/green-tea-000255.htm

Prostate Cancer and Green Tea Health Benefits

Laboratory studies have found that even green tea extracts have health benefits and prevent the growth of prostate cancer cells in test tubes.  In a large study conducted in Southeast China researchers found that the risk of prostate cancer declined with increasing frequency, duration and quantity of green tea consumption.  However, both green and black tea extracts also stimulated genes that cause cells 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. http://www.umm.edu/altmed/articles/green-tea-000255.htm

Skin Cancer and Green Tea Health Benefit

If you like to be in the sun, you better drink green tea every day! The main polyphenol in green tea is epigallocatechin gallate (EGCG).  Scientific studies suggest that EGCG and green tea polyphenols have anti-inflammatory and anti-cancer properties that may help prevent the onset and growth of skin tumors. http://www.umm.edu/altmed/articles/green-tea-000255.htm

Stomach Cancer and Green Tea Health Benefits

Laboratory studies have found that green tea polyphenols inhibit the growth of stomach cancer cells in test tubes.  In two studies that compared the health benefits of green tea drinkers with non-drinkers, researchers found that people who drank green tea were about half as likely to develop stomach cancer and gastritis (inflammation of the stomach) as those who did not drink green tea. http://www.umm.edu/altmed/articles/green-tea-000255.htm

Inflammatory Bowel Disease (IBD) and Green Tea Health Benefit

Green tea may help reduce inflammation associated with Crohn's disease and ulcerative colitis, the two types of IBD.  If green tea proves to be helpful for preventing colon cancer, this would be an added benefit for those with IBD because they are at risk for colon cancer. http://www.umm.edu/altmed/articles/green-tea-000255.html

Diabetes and Green Tea Health benefit

Green tea has been used traditionally to control blood sugar in the body.  Animal studies suggest that green tea may help prevent the development of type 1 diabetes and slow the progression once it has developed.  People with type 1 diabetes produce little or no insulin, a hormone that converts glucose (sugar), starches, and other foods into energy needed for daily life.  Green tea may help regulate glucose in the body. http://www.umm.edu/altmed/articles/green-tea-000255.htm

Liver Disease and Green Tea Health Benefit

Population-based studies have shown that men who drink more than 10 cups of green tea per day are less likely to develop disorders of the liver.  Green tea also seems to protect the liver from the damaging effects of toxic substances such as alcohol.  Animal studies have shown that green tea helps protect against the development of liver tumors in mice. http://www.umm.edu/altmed/articles/green-tea-000255.htm

Results from several animal and human studies suggest that one of the polyphenols present in green tea, known as catechin, may help treat viral hepatitis (inflammation of the liver from a virus).  In these studies, catechin was isolated from green tea and used in very high concentrations.  It is not clear whether green tea (which contains a lower concentration of catechins) confers these same benefits to people with hepatitis.

Weight Loss and Green Tea Health Benefit

Studies suggest that green tea extract may boost metabolism and help burn fat.  One study confirmed that the combination of green tea and caffeine improved weight loss and maintenance in overweight and moderately obese individuals.  However, a second study found that weight maintenance following weight loss was not affected by green tea.  Some researchers speculate that substances in green tea known as polyphenols, specifically the catechins, are responsible for the herb's fat-burning effect. http://www.umm.edu/altmed/articles/green-tea-000255.htm

Two large prospective studies found that the risk of developing symptomatic kidney stones decreased by 8% in women and 14% in men for each 8-ounce (235 mL) mug of tea consumed daily.  A study in rats concluded that the antioxidants in green tea may be involved in inhibiting calcium oxalate precipitation and thus kidney stone formation.  The implications of these findings for individuals with a previous history of calcium oxalate stone formation are unclear.  High fluid intake, including tea intake, is generally considered the most effective and economical means of preventing kidney stones.  However, tea consumption has been found to increase urinary oxalate levels in healthy individuals, and some experts continue to advise people with a history of calcium oxalate stones to limit tea consumption. http://lpi.oregonstate.edu/infocenter/phytochemicals/tea/