Suspicion that tea may be to blame was raised by the fact that the common link between the patients was their very high tea consumption. Each person drank 1 to 2 gallons (3.8 to 7.6 litres) of tea daily over the past 10 to 30 years.
Previously studies had estimated that the fluoride content of black tea stood at between 1 and 5 milligrams per litre but Dr Gary Whitford and his colleagues at the Medical College of Georgia in the US decided to investigate further because of the anecdotal evidence of the common tea link between the skeletal fluorosis patients.
Their research, the findings of which were presented this week at the 2010 International Association of Dental Research Conference in Barcelona, indicate that there could be much more fluoride in tea than previously thought. Results of their investigation indicate that there could be as much as 9 milligrams of fluoride in a litre of tea.
Most published studies on fluoride in tea use a method of measurement that does not account for the fluoride that combines with aluminum to form aluminum fluoride in tea. So instead, Whitford and his team used a diffusion method, which breaks the aluminum-fluoride bond so that all fluoride in the tea samples can be extracted and measured.
He tested seven brands of store-bought black tea, steeping each for five minutes in deionized water, which contains no fluoride. The amount of fluoride in each sample was 1.4 to 3.3 times higher using the diffusion method than the traditional method.
Commenting on the results, Whitford was careful to point out that the results should not be a cause of concern for moderate or even relatively heavy tea drinkers. Indeed, interest in tea has bloomed in recent years, as research reveals the positive health benefits of constituents like polyphenols.
He said: “The additional fluoride from drinking two to four cups of tea a day won’t harm anyone; it’s the very heavy tea drinkers who could get in trouble.”
“The bottom line is to enjoy your favorite tea, but like everything else, drink it in moderation.”