STUDY: Excessive Oolong and Black Tea May Weaken the Bones

A Western traveler enjoying a cup of local tea in Mongolia. (Visit this interesting travel blog)

In this web site I try to share ALL the facts and research results about health effects of tea drinking, not just the good and positive ones. I believe that as a tea lover and web site owner I owe that level of impartiality and objectivity to my readers.

Here is one such news from Japan: due to the high level of fluorine found in oolong and black teas, excessive consumption of these varieties can weaken human bones.

However I'm not sure what constitutes "excessive" drinking. Over 10 cups a day would certainly fit the bill.

A research team headed by Dr. Tetsuo Shimmura of Toyama Institute of Health in Japan presented the results of his research at a meeting of Japan Society for Biomedical Research on Trace Elements in Tokyo recently, according to a Kyodo news agency story.

Japanese researchers found that the amount of fluorine in these two kinds of tea exceed the same amount in tap water by 70 percent, based on a "test population" of 130 tap water samples. The average fluorine in tap water was 0.8 milligrams per liter. In mineral water it's under 2 milligrams per liter.

However, we should also remember that the subjects in this study were selected from Inner Mongolian Autonomous Region (in China), a region historically known to consume much higher than average quantities of black tea. So I believe this was not as random a population sample as a scientific study deserves.

"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 is reported saying.

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