Fluoride in tea: accumulation, dietary exposure, and future strategies for risk mitigation in food safety; a scoping review.
Level 5 - mechanism / opinion, no new human data
Scoping review of laboratory and dietary exposure studies (by design analogy, non-clinical)
PubMed 40504749 · doi:10.1080/10408398.2025.2516756
What was done
A scoping review synthesizing data from 88 global studies to evaluate fluoride bioaccumulation across tea plant parts, release rates under different brewing conditions, concentrations across tea types, and modeled dietary exposure risks.
What was found
Fluoride bioaccumulation was highest in mature leaves (808 µg/g) and lowest in roots (30.86 µg/g), showing a negative correlation with soil pH (rho = -0.76). Brewing time strongly correlated with fluoride release (r = 0.82, p < 0.001), with black tea bags reaching 6.01 mg/L at 30 minutes. Concentrations varied by type: brick tea (4.78 mg/L) > black tea (2.73 mg/L) > green tea (1.37 mg/L) > white tea (0.49 mg/L) > herbal tea (0.17 mg/L). Brick tea exceeded WHO guidelines across all age groups, while black tea posed risks for children aged 4 to 8 years (estimated daily intake 0.078 mg/kg/day) and adults in high-consumption regions.
Why it matters
This synthesis provides quantified exposure benchmarks across tea types and brewing methods to support consumer brewing guidance (such as steeping under 5 minutes) and food safety regulatory limits.
Limits
The review relies on modeled estimated daily intake rather than directly measured clinical health outcomes in human cohorts. Methodological quality, risk of bias, and geographic representation across the 88 included studies are not reported in the abstract.
Cited by
- supports Tea leaves concentrate fluoride from the soil, resulting in brewed tea containing approximately three parts per million of fluoride.