Human exposure to fluoride from tea (Camellia sinensis) in a volcanic region-Canary Islands, Spain.
Level 5 - mechanism / opinion, no new human data
Laboratory chemical analysis and exposure modeling with no direct human clinical data.
PubMed 32740848 · doi:10.1007/s11356-020-10319-9
What was done
Fluoride concentrations were measured in 90 commercial tea samples using potentiometry with a selective fluoride ion electrode. Investigators modeled theoretical human dietary exposure from consuming two 250 mL cups of tea brewed with local tap water from La Laguna (Canary Islands, Spain) and compared the results against the European Food Safety Authority (EFSA) Tolerable Upper Intake Level (UL).
What was found
Mixed tea samples contained the highest mean fluoride levels at 2.82 ± 1.11 mg/L, followed by black tea at 2.28 ± 0.79 mg/L. Modeled consumption of two 250 mL cups per day of mixed or black tea prepared with local tap water contributed 74.4% and 63.6%, respectively, of the 2.5 mg/day EFSA UL for children aged 4 to 8 years.
Why it matters
In volcanic areas where tap water contains baseline fluoride, regular tea consumption can supply a major fraction of a child's upper safe intake limit, increasing potential fluorosis risks.
Limits
This was an in vitro analytical and exposure-modeling study with no human biomarker measurements (such as urinary fluoride) or clinical health assessments. Total fluoride exposure across all other dietary and non-dietary sources was not measured.
Cited by
- supports Tea leaves concentrate fluoride from the soil, resulting in brewed tea containing approximately three parts per million of fluoride.