Fluoride contents in tea and soil from tea plantations and the release of fluoride into tea liquor during infusion

Fung, K. F.; Zhang, Z. Q.; Wong, Jonathan W C; Wong, Ming Hung

doi:10.1016/s0269-7491(98)00187-0

Cited by 206 publications

(140 citation statements)

References 8 publications

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“…If the leaves were rinsed for 0.5 min, the corresponding fluoride levels were lungjing (n=8) pouchong (n=8) tienguanyin (n=9) oolung (n=9) pureh ( (Fung et al, 1999), varied infusible fluoride contents in tea leaves from different growing areas are anticipated. Among these six kinds of tea drinks, pureh had the largest variation.…”

Section: Fluoride Concentration In Six Kinds Of Tea Drinksmentioning

confidence: 99%

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

Lung

Cheng

2007

J Expo Sci Environ Epidemiol

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Tea is the second most commonly consumed drink in the world. Excess fluoride intakes from tea drinks may cause health effects. This work assesses infusible fluoride levels in popular tea sold in Taiwan and evaluates potential exposure factors. Lungjing, pouchong, tienguanyin, oolong, pureh, and black tea specimens were purchased from different counties in Taiwan. Fluoride levels were evaluated in one complete cycle of tea making as well as at different calcium carbonate contents in water, with glass or porcelain teapots, and with/without adding sugar. Oolong tea leaves in each manufacturing step were also analyzed for infusible fluoride. Potential fluoride intakes and risks are estimated based on a national survey. Among six kinds of tea, black tea had the highest fluoride concentrations (8.6472.96 mg/l), whereas pureh (1.9772.70 mg/l) had the lowest levels. Higher percentages of infusible fluoride can be rinsed away from tea leaves curved lengthways compared to those curved end-to-end in the first 2.5 min. The use of glass or porcelain teapots and calcium carbonate content (up to 400 mg/l) in water would not affect infusible fluoride levels, whereas adding sugar increased the infusible fluoride in the first few minutes. In addition, it was found that the critical step during the manufacturing process affecting the percentage of infusible fluoride was ball rolling rather than fermentation. Furthermore, intakes of high amounts (Z5 l/week) of certain tea may result in excess risks of dental or skeletal fluorosis. Tea lovers could be exposed to excess fluoride and may be at risk of fluorosis.

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Section: Fluoride Concentration In Six Kinds Of Tea Drinksmentioning

confidence: 99%

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

Lung

Cheng

2007

J Expo Sci Environ Epidemiol

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“…The variations among leaf and bagged tea samples were much greater than the variation in duplicate samples. Since soil fluoride content would affect fluoride concentration in tea plantations (Fung et al, 1999 ), varied dissolvable fluoride contents in tea leaves from different growing areas were anticipated. Packaged tea samples had the least variation among them, probably due to their mass production process.…”

Section: Fluoride In Different Kinds Of Tea Drinksmentioning

confidence: 99%

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

Lung

Hsiao

Chiang

2003

J Expo Sci Environ Epidemiol

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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.

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Sofuoğlu

Kavcar

2008

Journal of Hazardous Materials

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Exposure and associated health risks for fluoride and trace metals in black tea were estimated. Fifty participants were randomly recruited to supply samples from the tea that they drink, and self-administer a questionnaire that inquired about personal characteristics and daily tea intake. Analyzed trace metals included aluminum, arsenic, barium, cadmium, cobalt, chromium, copper, manganese, nickel, strontium, and zinc. Fluoride and four metals (Al, Cr, Mn, Ni) were detected in all samples while barium was detected only in one sample. The remaining metals were detected in >60% of the samples. Fluoride and aluminum levels in instant tea bag samples were greater than in loose tea samples (p < 0.05) while the differences in elemental concentrations of loose and pot bag tea samples were not significant. Median and 90th percentile daily tea intake rates were estimated as 0.35 and 1.1 l/day, respectively. Neither fluoride nor aluminum levels in black tea were found to associate with considerable risks of fluorosis and Alzheimer's disease, respectively. However, carcinogenic risk levels for arsenic were high; R > 1.0 × 10 −6 even at the median level. According to sensitivity analysis, daily tea intake was the most influencing variable to the risk except for arsenic for which the concentration distribution was of more importance.

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Fluoride contents in tea and soil from tea plantations and the release of fluoride into tea liquor during infusion

Cited by 206 publications

References 8 publications

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

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

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

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

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