Green Tea May Prevent Kidney Stones
Study Shows Compound in Green Tea Extract May Block Formation of Kidney Stones
WebMD News Archive
Nov. 20, 2009 -- Drinking green tea may help prevent painful kidney stones.
A new study shows compounds in green tea extract make it more difficult for
certain kidney stones to form.
Kidney stones affect about 5% of the world's population. They occur when
abnormally high concentrations of minerals, such as calcium, accumulate in the
urinary tract and clump together to form crystals and potentially painful
Most kidney stones contain calcium, and the most common stone type is
calcium oxalate. Chinese researchers found that green tea extract bonds to
calcium oxalate and makes the resulting crystals a different shape, which makes
them less likely to clump together and form large kidney stones.
The smaller crystals and stones are then passed harmlessly through the
In the study, published in CrystEngComm, Xudong Li of Sichuan
University in Chengdu, China, and colleagues examined the effects of green tea
concentrate on calcium oxalate crystallization using a variety of advanced
scanning and imaging techniques.
The results showed that as the amount of green tea extract applied
increased, the calcium oxalate crystals became flatter and flatter.
Researchers say flatter crystals form less stable kidney stones that break
up more easily.