Sequential Infusions of Black Tea: Multi-Element Exposure Trade-Offs of Discarding the First Brew

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Abstract
Sample-level data preserving dependence among sequential tea infusions remain scarce. This secondary analysis examined a CC BY 4.0 dataset containing 34 black teas with three linked sequential infusions per sample. We reconstructed the cumulative element mass after consuming all three infusions versus discarding the first. The primary hazard index (HI) excluded Pb because no health-protective threshold can be established; Pb exposure and a legacy Pb-based HI were reported separately. At 10 g dry tea/day and 65 kg body weight, the median Pb-excluded HI decreased from 0.419 (IQR 0.258–0.497) to 0.260 (0.157–0.326), with a mean relative reduction of 37.1% (95% bootstrap CI 34.4–39.8%). No sample exceeded HI = 1, but this does not establish safety. When beverage volume was held at 80 mL, the mean HI reduction was only 5.7% (1.5–9.7%), showing that much of the apparent benefit reflected lower consumed volume. The total-As-based As HQ remained below one. Total-As cancer screening decreased by 35.9%; however, the proportion above 10−4 ranged from 0% to 64.7% across assumed inorganic-As fractions of 10–100%, demonstrating strong speciation dependence. Discarding the first infusion also reduced the estimated brewed yields of Cu, Se, and Zn by amounts equivalent to 2.4% of the adult Cu RDA, 2.5% of the Se RDA, and 0.4–0.5% of the Zn RDA; these estimates describe elemental yield in the beverage rather than absorbed nutrient intake. Overall, discarding the first infusion reduces estimated hazard indices primarily through decreased beverage volume rather than selective removal of toxic elements. Because extraction kinetics heavily depend on preparation techniques—such as traditional two-pot brewing—and regional tea chemistry, these findings cannot be directly extrapolated to Turkish teas. Instead, this study establishes a standardized exposure framework that highlights a critical knowledge gap and underscores the need for paired empirical studies evaluating local cultivars under authentic preparation practices.
Funding Information
  • Recep Tayyip Erdogan Üniversitesi (020260090070665)

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