Why tea is good for you

You've probably heard it said more than once: drinking tea is good for you. It's easy to dismiss these claims as nothing more than a marketing ploy, but scientific studies have been carried out proving that yes, drinking tea does have beneficial effects on your health.

Tea is rich in polyphenols, chemicals that have antioxidant properties. Antioxidants may protect the body against some common health problems and certain effects of aging. The most widely studied polyphenol are flavonoids, which are also found in fruits, red wine and chocolate.

In his book "Tea and Health," Fang Zhou lists the organic compounds in tea as protein, amino acids, alkaloids, polyphenols, carbohydrates, organic acid, fats and lipids, vitamins (A, B1, B2, B5, B11, C, D, E, K, P) and enzymes.

Here's what the latest studies have found about tea and its beneficial effects on health:

Against heart disease. Green tea helps reduce an important rick factor for heart disease. In a study conducted at the Athens Medical School in Greece, researchers found that drinking green tea improves the function of endothelial cells lining the circulatory system. Endothelial dysfunction is one of the risk factors for heart disease.

Dr. Charalambos Vlachopoulos, one of the researchers involved in the study, said that flavonoids in green tea could have more potent antioxidants than black tea because there has been no oxidisation.

Dr. Vlachopoulos also cited recent studies showing that tea had “potent anticarcinogenic effects” because of its antioxidant properties. Polyphenols can block the action of enzymes that cancers need for growth and they can deactivate the Epigallocatechin-3-gallate, or EGCG is the polyphenol most strongly related to cancer prevention.

Lowers cholesterol. According to the University of Maryland Medical Center, green tea lowers total cholesterol and raises the level of good cholesterol. One study showed that men who drink green tea are likely to have lower total cholesterol than those who do not drink green tea. One animal-base study suggested that polyphenols in tea may block the intestinal absorption of cholesterol and promote its excretion from the body.

Against dementia. The American Journal of Clinical Nutrition cited a 2006 study that showed elderly Japanese people who drank more than 2 cups of green tea per day were at lower risk for dementia. The study tested cognitive functions among the subjects.

Against the effects of aging. Polyphenols in tea have been found to be 18 times more effective than Vitamin E in defending the body against the effects of aging. According to Fang, 1 gram of tea equals 8 milligrams of SOD (super oxide dismutase), an important anti-oxidant.

For the skin. Tea polyphenols help protect the skin against ultraviolet rays. Tea extracts have also been found to help treat damaged skin in cancer patients, a study conducted by Frank Pajonk from the University of California in Los Angeles and his colleagues from the University of Frieburg in Germany showed. Tea's high polyphenol content likely helps reduce inflammation, the study said.

For weight loss. In clinical trials conducted by the University of Geneva and the University of Birmingham, green tea has been found to raise metabolic rates and speed up fat oxidation. Catechin polyphenols in tea also raise the rate at which calories are burned, which could be beneficial for weight loss.

Boosts mental alertness. Human trials conducted in September 2007 found that the amino acid L-theanine, found exclusively in tea plants, can help boost mental alertness. John Fox, PhD, professor of neuroscience, biology and psychology at City College of the City University of New York, found that theamine affects the brain's neurotransmitters and increases alpha brain-wave activity, resulting in a calmer yet more alert state of mind.

Tea also contains caffeine, which has been linked to a reduction in the likelihood of Parkinson's disease and a temporary increase in short term memory.

Boosts the immune system. Brigham and Women's Hospital found in a 2003 study that theanine could help improve the body's immune system response when fighting infection. Theanine could boost the disease-fighting capacity of gamma delta T cells. Black tea drinkers showed up to five times more anti-bacterial proteins in their blood samples.

Lowers stress hormone levels. A study by University College of London researchers found that drinking black tea lowers stress hormone levels. Just 50 minutes after a high stress event, regular black tea drinkers, who have been rinking 4 cups of black tea daily for a month, had a 20 percent more drop in cortisol levels than the control group. Blood platelet activation, which is linked to blood clotting and the risk of heart attacks, was also lower for tea drinkers.

Against bad breath. Researchers at the University of Illinois at Chicago found that polyphenols prevent the growth of bacteria responsible for causing bad breath.