Abstract
This study aimed to measure the fluoride concentrations of successive infusions of tea steeped from the same tea bag, with relative risk of fluorosis in mind. 250 ml infusions of 37 different tea brands were steeped with deionized distilled water at an initial temperature 85°C. For each different tea brand, after 10 minutes the first infusion was emptied and 250 ml of fresh deionized distilled water at 85°C was added to the original tea bag; this step was repeated at the 30 minute mark as well, with the experiment ending at the 50 minute mark. All infusions were analyzed for fluoride concentration using a fluoride ion-specific electrode and millivolt meter. Caffeinated teas (n=19) had a mean fluoride concentration of 1.32 µg/ml (SD±0.81) for the first infusion, which reduced to 0.34 µg/ml (SD±0.18) for the second infusion and then 0.14 µg/ml (SD±0.06) for the third infusion. Decaffeinated teas (n=7) had a mean fluoride concentration of 3.10 µg/ml (SD±0.64) for the first infusion, which reduced to 0.64 µg/ml (SD±0.16) for the second infusion and then 0.21 µg/ml (SD±0.05) for the third infusion. Herbal teas (n=11) had a mean fluoride concentration of 0.03 µg/ml (SD±0.02) for the first infusion, which reduced to 0.03 µg/ml (SD±0.01) for the second infusion and then 0.02 µg/ml (SD±0.01) for the third infusion. Successive tea infusions from the same bag contain lower fluoride concentrations than the first. First infusions of tea, specially non-herbal, present a higher risk for fluorosis than successive infusions.
Keywords: Decaffeinated tea, fluoride, fluoride in tea, fluorosis, herbal tea, tea.
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