It was once commonly thought that tea had the opposite effect, that is, that it caused dehydration, but researchers at King's College in London have debunked that notion.

Although it is true that high doses of caffeine have a dehydrating effect, caffeine-containing beverages still provide a net gain of fluid, said Dr. Carrie Ruxton, the Public Health Nutritionist who led the study.

Tea is high in flavonoids, or polyphenol antioxidants, which protect cells. Researchers believe they help guard against heart disease and cancer. Tea may also help prevent bone loss and tooth decay.

Though three cups of tea have been found to be beneficial, four or more cups -- even as many as six to nine, the amount consumed by some tea-loving Brits -- can do even more good, the latest research suggests.

However, those tea-loving types tend to be in the over-40 segment of the population. Younger people in the UK are drinking less tea and likely consuming more soft drinks instead.

The researchers' findings are published in the European Journal of Clinical Nutrition.

The National Center for Complementary and Alternative Medicine, part of the US National Institutes of Health, lists some of the benefits of green tea: