Tea and bone health: Findings from human studies, potential mechanisms, and identification of knowledge gaps.

The population of the developed world is aging. With this aging population, strategies for prevention rather than treatment of chronic disease, such as osteoporosis, are essential for preserving quality of life and reducing health care costs. Tea is the second most consumed beverage in the world and is a rich source of flavonoids that may benefit bone health. There is strong evidence from human studies that habitual tea consumption is positively associated with higher BMD at multiple skeletal sites, while the association with fracture risk is less clear. Fracture studies demonstrate a reduction or no difference in fragility fracture with tea consumption. There are key questions that need to be answered in future studies to clarify if higher consumption of tea not only supports a healthy BMD, but also reduces the risk of fragility fracture. And if the latter relationship is shown to exist, studies to elucidate mechanisms can be designed and executed. This review discusses findings from epidemiological studies as well as potential mechanisms by which flavonoids in tea may mediate an effect, and identifies key knowledge gaps in this research area.