Modulatory Effects of Tea Components with Different Fermentation Degrees on Fluoride Bioavailability in Rats

Tea offers health benefits, but some teas accumulate high fluoride (F), posing fluorosis risks. However, the roles of individual tea components in regulating F bioavailability remain unclear. This study investigated the effects of major tea constituents on F metabolism in male rats (n = 5/group) administered F (40 mg/L) alone or with graded doses of epigallocatechin gallate (EGCG, 150-450 mg/kg); theaflavins, thearubigins, and theabrownin (TFs, TRs, TB, 200-800 mg/kg each); tea polysaccharides (TPSs, 25-250 mg/kg); and calcium and aluminum (Ca, Al, 800-3200 µg/kg each) via gavage. Pharmacokinetic analysis of plasma F (0-480 min) and fecal F excretion were assessed. The result showed that high-dose EGCG (450 mg/kg) reduced C_max by 61.76% and total exposure (AUC_0-t) by 37.48% compared to the control, while significantly increasing fecal F by 26.79% (p < 0.05). TB (800 mg/kg) delayed F absorption by prolonging T_max from 18 to 30 min and reduced C_max by 35.38% (p < 0.05). TPS (250 mg/kg) decreased C_max by 51.72% and AUC_0-t by 24.38% (p < 0.05). Ca and Al (800-3200 µg/kg) reduced C_max by 39.19-69.62%, and low-dose aluminum (800 µg/kg) increased fecal F by 35.58% (p < 0.05). These findings elucidate distinct roles of tea constituents in mitigating F bioavailability, providing a scientific basis for tea safety assessment and dietary interventions against F overexposure.