Chinese teas exhibited the highest fluoride content, measuring at 6.83 ppm.
Consequently, one typical 240 ml beverage cup of Chinese green tea would contain 1.6 mg of fluoride, surpassing more than twice the quantity found in drinking two liters of water fluoridated at 0.7 ppm.
A standard tea cup (6 oz - 177 ml) would contain 1.20 mg of fluoride.
A small 100ml traditional Chinese tea cup would contain as much fluoride as if one were to drink one liter of fluoridated water (4 x 8 oz glasses).
This quantity is likely to increase even more with an extended steeping time (Mazurek et al., 2023).
Ing ME, Magnuson BE, Frantz DL - "Fluoride Content in Asian Produced Green Teas" J Can Dent Assoc 87:l3 (2021)
https://jcda.ca/l3
Abstract
Background:
This study determined the fluoride content of green tea from various parts of Asia, where green tea originates.
Methods
We brewed 2.5 g each of 4 types of green tea (from China, South Korea, Japan and Sri Lanka) using deionized water heated to boiling. Water was cooled to 71°C, then tea was steeped for 2 minutes. This process was repeated 20 times, thus providing 20 samples for each tea type. In addition, 20 control samples of deionized water were brewed to the same specifications. Samples were analyzed using a fluoride probe, and statistical power was calculated.
Results:
The tea samples from different countries varied in the amount of fluoride they contained. The Chinese sample contained the most fluoride, while the Japanese sample contained the least. Means and interquartile ranges of fluoride concentration were calculated for each sample: Sri Lanka 3.58 ppm (0.1425), Chinese 6.83 ppm (0.140), South Korean 5.36 ppm (0.0975), Japanese 1.88 ppm (0.1375) and control 0.33 ppm (0.0078).
Conclusions:
The origin of tea and environmental factors, such as pollution, groundwater, air and the soil in which it was grown appear to directly affect the amount of fluoride that accumulates in the plants. Considering the fluoride content revealed by this study, green tea consumption habits should be taken into account when prescribing adjunct fluoride therapy as part of a preventative program for patient care.
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Mazurek A, Kowalska G, Włodarczyk-Stasiak M, Wyrostek J, Kowalski R - "The Influence of the Preparation of Tea Infusion on the Content of Fluoride and the Assessment of Health Risk for the Consumer in Poland" Applied Sciences 13(8):5075 (2023) https://doi.org/10.3390/app13085075
https://www.mdpi.com/2076-3417/13/8/5075