Fluoride concentrations in three types of commercially packed tea drinks in Taiwan

Tea is a popular drink around the world. It is also one of the major sources of fluoride intake. The objectives of this study were to assess fluoride concentrations in popular non-, semi-, and full-fermented tea drinks sold on the Taiwan market. Concentration differences among three types of commercially available tea drinks (tea leaf, tea bag, and packaged tea beverage) were explored. Several influential factors in intake concentrations were evaluated. The acute threshold intake (ATI) and allowable daily intake (ADI) of those tea drinks were also estimated. For each commercial type, samples from the most popular tea in one particular fermentation degree (non, semi, and full) were randomly purchased and analyzed for fluoride concentrations. Fluoride levels in different rounds of tea, in different containers, and with different ratios of water and tea leaf were also assessed. In total, 132 tea samples were analyzed. The mean fluoride concentrations in leaf tea without the first round, leaf tea with the first round, bagged tea, and packaged tea were 7.04, 7.79, 5.37, and 25.7 mg/l, respectively. Most of the intake concentrations in those samples exceeded 4 mg/l F, the lower bound of fluoride levels reported in the literatures to be associated with a lower IQ in children and a higher risk of bone fracture. Fluoride concentrations in packaged tea were the highest among the three types of commercially available tea. For studied leaf and bagged tea, almost a constant amount of fluoride was infused from the same amount of tea leaf regardless of the water volume. Besides this, making tea with glass or pottery tea makers would not affect fluoride intake concentrations. Acute intoxication is unlikely to occur. However, tea lovers in high fluoride content areas shall consider limit their consumption of tea drinks to avoid potential chronic effects.