Green tea has been hailed as a health hero recently, credited with speeding metabolism and promoting weight loss, warding off colds and flu, and even protecting against tooth decay. But its greatest value, according to doctors and researchers, is its powerful punch against serious diseases, most notably cardiovascular disease. In fact, one study of more than 40,000 men and women in Japan found that green-tea drinkers outlived their tea-shunning counterparts by a measure of 16 percent over 11 years. Is this popular beverage, enjoyed widely in Asian countries such as Japan and gaining momentum in Western societies, really the key to living longer?

It may very well be, according to experts. Green tea, which is made with unfermented leaves, has high levels of disease-fighting antioxidants called polyphenols. Polyphenols work to neutralize disease-causing free radicals that alter cells. A recent small study in Greece found that just three to four cups of green tea daily improves the functioning of the lining of cardiac blood vessels, making them more pliable and able to withstand changes in blood pressure. It also may be effective against the formation of blood clots, a big cause of heart attacks. And studies show that green tea lowers total cholesterol while raising levels of HDL, or "good" cholesterol-all things that can help you live longer.

But green tea's wonders are not limited to the heart and vascular system. People may be able to keep their diabetes under control with the help of green tea. And according to the University of Maryland Medical Center, studies reveal a reduced risk of several cancers in green-tea drinkers:

Bladder cancer. One study of women who drank black tea and powdered green tea found a lower incidence of bladder cancer. Another study showed that bladder-cancer patients who drank green tea had significantly better five-year survival rates.

Breast cancer. While it may not be effective in late-stage cancer, evidence seems to point to a protective effect among women with early-stage breast cancer. Women in several studies who drank lots of green tea experienced less spreading of their cancer and fewer recurrences.

Ovarian cancer. In one Chinese study, women with ovarian cancer who drank at least one cup of green tea daily lived longer than those who didn't. The more tea they drank, the longer they lived.

Other cancers reported to be affected by green tea include esophageal, lung, pancreatic, prostate, skin and stomach cancers.

Given the purported health benefits of this beverage, it stands to reason that enjoying it on a regular basis may help you live a longer, healthier life. What better reason to put on the kettle and indulge in a cup now?