Tea increases bone mineral density.

Wu CH, Yang YC, Yao WJ, et al: Epidemiological evidence of increased bone mineral density in habitual tea drinkers. Arch Intern Med 2002; 162:1001-1006

Habitual tea consumers of six years or more have higher total body, lumbar spine, and hip bone mineral density than do nonhabitual tea drinkers, with the greatest benefit seen after ten years. Possible reasons include the inhibition of bone resorption in vivo and the effects of polyphenols, tannins, flavonoids, and dietary fluoride, which can alleviate osteoporotic progression. Tea contains more than 4,000 chemical compounds that can affect the human body, including polyphenols known to help prevent cardiovascular disease, atherosclerosis, and cancer. These results were found in a recent study of 1,037 male and female tea-drinkers in Taiwan. Habitual tea drinkers were defined as those who drank tea "habitually once a week for at Least six months." No difference was found among those who had green (nonfermented), oolong (partially fermented), or black (fermented) tea. After water, tea is the most regularly consumed drink by most adults in the world, and further study is needed to determine if populations other than Asians see the same results.