Fluoride in tea: accumulation, dietary exposure, and future strategies for risk mitigation in food safety; a scoping review

Tea, the world's most consumed nonalcoholic beverage after water, naturally accumulates fluoride (F-) from the soil. This scoping review synthesizes data from 88 global studies to evaluate F- levels in tea and associated health risks. Findings reveal F- bioaccumulation follows mature leaves (808 µg/g) > stems > buds > roots (30.86 µg/g). Brewing time strongly correlates with F- release (r = 0.82, p < 0.001), with black tea bags reaching 6.01 mg/L after 30 min. Fermentation and smaller leaf particles further elevate F-, while soil pH shows negative correlation (ρ = -0.76). F- concentrations vary significantly by tea 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 consumption exceeds WHO guidelines across all age groups, while black tea poses risks for children (4-8 years: EDI 0.078 mg/kg/day) and adults in high-consumption regions. Excessive intake may cause dental/skeletal fluorosis, chronic kidney disease, and acute toxicity (headache, vomiting). These findings highlight the need for monitoring F- intake in high-risk populations, optimizing brewing practices (<5 min), and developing standardized regulations for tea products. Balanced approaches should ensure adequate F- intake in deficient regions while mitigating risks in endemic fluorosis areas.