Green tea, native to China and India, has been consumed and hailed for its health benefits for centuries globally, but has only recently gained popularity in the US. It is made from un-oxidized leaves and is one of the less processed types of tea (with white tea the least) and therefore contains one of the most beneficial polyphenols.
Green tea is the best food source of a group called catechins. In test tubes, catechins are more powerful than vitamins C and E in halting oxidative damage to cells and appear to have other disease-fighting properties. Studies have found an association between consuming green tea and a reduced risk for several cancers, including, skin, breast, lung, colon, esophageal, and bladder.
1. Anti-Cancer Benefits
The study of green tea and cancer prevention is still in early stages, but the results are promising. Researchers suspect that polyphenols in green tea help kill cancer cells and stop their progression, an important role to prevent various cancers.
In a study of 472 women with breast cancer, those who drank the most green tea experienced the least spread of the disease. Researchers also found that women in the early stages of breast cancer who drank at least five cups of green tea every day during their diagnoses were less likely to have the disease recur after the completed treatment.
In looking at more than 35,000 women in the Iowa Women’s Health study, those who drank two or more cups of tea a day were almost 30 percent less likely to develop colon cancer than those who rarely drank tea.
One Chinese study found that men who drank more than three cups of tea a day reduced their risk of prostate cancer by 70 percent. In skin cancer studies, lab animals that were given green tea developed 1/10th as many tumors as animals that were given water.
2. Lowers Cholesterol Levels
Research shows that green tea lowers total cholesterol and raises HDL (“good”) cholesterol in both animals and humans. One population-based clinical 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 cholesterol from being absorbed in the intestine and also help the body get rid of cholesterol. In another small study of male smokers, researchers found that green tea significantly reduced blood levels of harmful LDL cholesterol.
3. Benefits on Diabetes
Green tea has been used traditionally to control blood sugar levels. Animal studies suggest that green tea may help prevent the development of type 1 diabetes and slow the progression once it has developed. In people with type 1 diabetes, their bodies make little or no insulin, which helps convert glucose or sugar into energy. Green tea may help regulate glucose in the body.
4. Protects Liver
Population-based clinical studies have shown that men who drink more than 10 cups of green tea per day are less likely to develop liver problems. 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 liver tumors in mice.
Results from several animal and human studies suggest that one of the polyphenols in green tea, known as catechin, may help treat viral hepatitis, an inflammation of the liver. In these studies, catechin was used by itself in very high amounts. It is not clear whether green tea, which has a lower concentration of catechins, would have the same benefits.
5. Soothes Arthritis
To cut down on aches and pains, try to sip four cups of green tea a day. The tea contains quercetin, a chemical compound that acts as a powerful anti-inflammatory and antioxidant. In a recent study conducted at Case Western Reserve University, researchers gave mice the equivalent of four cups of green tea a day, then gave them a substance that would normally produce rheumatoid arthritis. The tea-drinking mice were far less likely to develop arthritis than mice that drank water. According to the Iowa Women’s Health Study, women who drank more than three cups of tea a day were 60 percent less likely to develop rheumatoid arthritis than non tea drinkers. Other research has found that tea’s polyphenols—antioxidant properties—are also anti-inflammatory and improve arthritis-related immune responses.
6. Boosts Brain Functions
Researchers from the Netherlands confirmed in a recent study that two green tea compounds, L-theanine and caffeine, can significantly boost levels of attention and alertness, building on what is already known about tea’s brain benefits. Green tea is less likely to make you jittery and anxious than other energy-boosting drinks, because it contains lower levels of caffeine than other teas or coffee. In another study published in the American Journal of Clinical Nutrition, researchers discovered that drinking just one cup of green tea a day made people age 55 and older 38 percent less likely to experience a decline in their mental abilities. Drinking a second cup daily made them 54 percent less likely to show mental declines.
7. Alzheimer’s Disease
Evidence of a positive link between drinking green tea and Alzheimer’s disease is weak. A 2010 laboratory study using animal cells found that a green tea preparation rich in antioxidants protected against the nerve cell death associated with dementia and Alzheimer’s disease. Whether these lab results can be reproduced in human trials remains to be seen. As such, the findings do not conclusively show that green tea combats Alzheimer’s disease.
8. Skin Benefits
A University of Miami study found that even a mild dose of green tea’s antimicrobial and antioxidant compounds erased almost two-thirds of pimples from people with mild to moderate acne when used twice daily for six weeks. To benefit, make a cup of green tea, let cool, and use as a face wash, or lay the tea bag directly on the skin to act as a compress for particularly bad pimples. For oily skin, mix peppermint tea with the green tea for an oil blasting wash; and to calm inflamed skin, add chamomile to green tea for a soothing rinse.
9. Urinary Tract Infections
Drinking 2 to 3 cups of green tea daily can help clear up a urinary tract infection. The tea contains antioxidants that one study found can reduce bladder inflammation. Other studies have shown that green tea drinkers have a 40 percent lower incidence of UTIs than those who did not drink green tea.
10. Relieves Allergies
Green tea is rich in flavonoids, plant chemicals that protect against inflammation. For struggles with allergies, try drinking a few cups of tea a day and see if the sinus inflammation goes down.
11. Reduces Puffy Eyes
Some herbalists claim that tea bag compresses speed the healing of a black eye, but to calm puffy tissues, take two wet green tea bags, place them on tired or swollen eyes, and lie down for 15 to 20 minutes as the tea soothes and refreshes.
12. Reduces Asthma Symptoms
The antioxidant quercetin, found in green tea, has been shown to inhibit the release of inflammatory substances from mast cells, which are involved in allergic responses. (This is how some asthma drugs work.) Try drinking two cups of green tea day to keep asthma symptoms at bay.
13. Anti-Stress Benefits
Green tea is lower in caffeine than most other teas, so you may be able to drink the five cups a day that lowered psychological stress in a large group of Japanese people in a recent study done at Sendai’s Tohoku University Graduate School of Medicine. The researchers didn’t identify any particular component of green tea that might have been soothing, but animal studies suggest that one compound, EGCC, had both sedative and hypnotic effects that tamp down the body’s production of stress chemicals.
14. Bone Health Benefits
Routine tea consumption, especially for more than 10 years, has been associated with decreasing the risk of osteoporotic fractures. It’s thought that tea helps diminish bone loss through antioxidant and anti-inflammatory activity. Additionally, tea’s health-promoting properties are thought to suppress the breakdown of bone while increasing the amount and activity of bone building cells.
15. Guards against Hepatitis
Viral hepatitis is often triggered by high levels of iron in the liver. Green tea lowers iron levels throughout the body, so may have a direct anti-viral effect against certain strains of hepatitis.