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

Abstract

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.

Potential exposure and risk of fluoride intakes from tea drinks produced in Taiwan

“…The variation of the first four tea drinks was close to the variation of triplicate samples, while the large variation of pureh was mainly due to the low fluoride concentrations. In addition, previous study showed that fluoride infused from black tea did have higher variation compared to other tea drinks (%CV of black tea was up to 20%, Lung et al, 2003); this may account for high variation of black tea in this experiment. Thus, our results suggest that the use of glass tea makers or porcelain teapots would not affect fluoride levels in tea infusions for these tea leaves.…”

“…However, porcelain and pottery teapots are used in traditional tea making. It has been reported that there was no difference in fluoride concentrations by using glass or pottery tea makers (Lung et al, 2003). Thus, we only assessed fluoride levels in tea infusions in glass and porcelain containers.…”

An exposure and risk assessment for fluoride and trace metals in black tea

“…Hudaykuliev et al [21] reported a range of F content for Turkish teas as 88-289 mg/kg which corresponds to 0.8-2.6 mg/l infusion concentrations with the assumption of water-soluble fraction is 90%. Higher levels were reported from other parts of the world as 0.45-6.5 mg/l [7,10,11,18]. The highest concentrations (4.8-7.3 mg/l) occurred in brick tea infusions after 6 h of infusion [19].…”

“…The estimated mean daily tea intake in this study (0.49 l/day) is about half the assumed consumption by Kalayci and Somer [17], but it is approximately three times higher than Fernandez et al [30] assumption. Nevertheless, it is much less than the consumption rates (0.8-0.9 l/day) in Southern Asia [11,18].…”

“…While beneficial effects were investigated against cancer [1,2], vascular diseases [3], hypertension [4], and dental caries [5], tea was associated with dental [6] and skeletal [7] fluorosis, and Alzheimer's disease [8] due to accumulation of fluoride (F) and aluminum (Al), respectively, in the plant. The impact of tea drinks on human health has been observed, and trace elemental content of tea has been investigated in Southern Asian countries where tea is a traditional drink consumed in large quantities, such as in China [9], India [10], Taiwan [11], and Tibet [6] for fluoride, and in China [12], and Thailand [13] for aluminum and other trace elements. Recently, infusion fluoride concentrations of up to 6.5 mg/l [7] and brand name bottled tea concentrations of up to 4.1 mg/l [14] were measured in the US.…”