Prolonged consumption of tea, especially the oolong and black variety, could weaken human bones due to the presence of toxic fluorine in tea beverages, Japanese researchers say.

The researchers, including Tetsuo Shimmura, who is senior research scientist of Toyama Institute of Health in Toyama Prefecture, reported the existence of the chemical in beverages such as oolong tea and black tea at a meeting of Japan Society for Biomedical Research on Trace Elements in Tokyo recently, Kyodo news agency reported.

They confirmed that the fluorine content in tea exceeds the standard for tap water in terms of density in about 70 per cent of the 130 instances they analysed.

There is no criterion for the amount of fluorine in green tea, black tea and oolong tea beverages, but for raw water and tap water it is under 0.8 milligrams per liter and for mineral water it is under 2 milligrams per litre.

“In our study of people’s health in the Inner Mongolian Autonomous Region (in China), we found that the bones of those who consumed water and beverages containing high fluorine density over a long time could develop a propensity to break,” Shimmura said.

“They are not in any immediate risk. However, it is desirable that a standard be set and displayed for tea drinks.

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