IADR Abstract Archives
Fluoride Content in Green Tea
Objectives: Camelia sinensis, the tea plant, is a natural bioaccumulator of fluoride, which is uptaken and incorporated into the plant when it is grown in fluoride containing soil. The fluoride is released upon brewing the tea. This study measured the fluoride released from four Asian green teas.
Methods: Asian sencha variety loose leaf green teas were obtained from Sri Lanka, South Korea, China, and Japan. Each tea was brewed 20 times, each time using 2.5 grams of loose-leaf tea and 120 cm³ of deionized water. Brewing time was two minutes and brewed tea was analyzed using a fluoride probe. As control, the above process was done using deionized water without any tea. All reusable articles used in the experiment were cleaned using deionized water between experimental runs.
Results: The normality assumption was checked and violated so nonparametric measures were conducted in this analysis. Medians and interquartile ranges of fluoride concentrations were reported for each tea type; Chinese 6.83ppm (0.14), Korean 5.36ppm (0.10), Ceylon 3.58ppm (0.14), and Japanese 1.88ppm (0.14). A Kruskal-Wallis test found a significance difference between groups of tea (H=95.06, df=4, p-value<0.0001). Nonparametric post-hoc tests found significant differences between the Chinese tea, with both Ceylon and Japanese tea, and significant differences between Korean tea with Japanese tea. All teas were significantly different from the control group.
Conclusions: The Chinese tea had the highest amount of fluoride released while the Japanese had the lowest. Chinese tea was not significantly different though from the second highest, Korean, but was different than both Ceylon and Japanese tea. This study showed that teas from different countries varied in the amount of fluoride they contained. When considering a person’s daily fluoride intake, tea consumption habits and origin of tea should be evaluated.
Methods: Asian sencha variety loose leaf green teas were obtained from Sri Lanka, South Korea, China, and Japan. Each tea was brewed 20 times, each time using 2.5 grams of loose-leaf tea and 120 cm³ of deionized water. Brewing time was two minutes and brewed tea was analyzed using a fluoride probe. As control, the above process was done using deionized water without any tea. All reusable articles used in the experiment were cleaned using deionized water between experimental runs.
Results: The normality assumption was checked and violated so nonparametric measures were conducted in this analysis. Medians and interquartile ranges of fluoride concentrations were reported for each tea type; Chinese 6.83ppm (0.14), Korean 5.36ppm (0.10), Ceylon 3.58ppm (0.14), and Japanese 1.88ppm (0.14). A Kruskal-Wallis test found a significance difference between groups of tea (H=95.06, df=4, p-value<0.0001). Nonparametric post-hoc tests found significant differences between the Chinese tea, with both Ceylon and Japanese tea, and significant differences between Korean tea with Japanese tea. All teas were significantly different from the control group.
Conclusions: The Chinese tea had the highest amount of fluoride released while the Japanese had the lowest. Chinese tea was not significantly different though from the second highest, Korean, but was different than both Ceylon and Japanese tea. This study showed that teas from different countries varied in the amount of fluoride they contained. When considering a person’s daily fluoride intake, tea consumption habits and origin of tea should be evaluated.