OSAKA - The ingredient that makes black tea bitter helped prevent bones from breaking in experiments with mice, researchers from Osaka University and elsewhere have said in a report carried in the Feb. 24 issue of the online edition of the Nature Medicine science journal.
The researchers said in the report that they want the findings to lead to the development of preventive medicine for osteoporosis.
Bones have osteoblast cells, which make the hard tissues of calcium, and osteoclast cells, which destroy old bone tissues. A bone's strength is maintained by a balance of these cells.
When a person grows old, this balance can fail, leading to osteoporosis.
Researchers including Osaka University Prof. Masaru Ishii and Assistant Prof. Keizo Nishikawa gave polyphenol, an ingredient found in black tea that gives off a bitter taste and helps determine the colour of the tea, to mice suffering from osteoporosis as a result of having excessive osteoclast cells.
When they injected the mice with polyphenol once every three days, the mice were found to have fewer osteoclast cells, and their bone strength recovered to normal levels.
However, the study also showed that a person weighing 60 kilograms would need to drink 60 cups of black tea at one time to expect the same effect shown in the experiment with mice. Drinking a normal amount of black tea does not seem to improve bone strength.
"If a medicine or a supplement using polyphenol is developed, I think it could contribute to preventing osteoporosis," Nishikawa said.Speech