Catechin Bioavailability Is Reduced in Obese Persons Without Altering Gut Microbial-Derived Valerolactones Following Consumption of a Green Tea Extract Confection

Objectives Green tea extract (GTE) protects against obesity in rodents by reducing gut permeability that otherwise provokes endotoxemia-mediated inflammation. However, whether obesity affects catechin bioavailability and microbial metabolism is unknown. We hypothesized that obesity will reduce catechin bioavailability by increasing microbial biotransformation of catechins. Methods Obese persons (n = 10 M/7F; 33.5 ± 0.7 kg/m2) and age-matched healthy persons (n = 10 M/9F; 21.7 ± 0.4 kg/m2) completed a pharmacokinetics (PK) trial in which a GTE confection [290 mg epigallocatechin gallate (EGCG), 87 mg epigallocatechin (EGC), 39 mg epicatechin (EC), 28 mg epicatechin gallate (ECG)] was ingested prior to collecting plasma at 0, 0.25, 0.5, 1, 2, 3, 5, 8, 10, and 12 h and urine from 0–4, 4–8, 8–12, and 12–24 h. Stool samples were collected and gut permeability was assessed prior to the 12-h PK trial. Plasma and urinary catechin/catechin-derived microbial metabolites were assessed following enzymatic hydrolysis by LC-MS. Results Regardless of health status, relative bioavailability, based on plasma area under the curve (AUC0–12 h), of GTE catechins were: EGCG > EGC > ECG > EC. However, obese persons had 24–27% lower plasma AUC0–12 h for the four catechins compared to lean persons (P < 0.05). They also had 18–36% lower maximum plasma concentrations (Cmax) of GTE catechins but 12 h plasma catechin concentrations were unaffected by obesity status (P > 0.05). 3ʹ,4ʹ-γ-valerolactone (3,4-VL) was detected in the plasma of all participants, while 3ʹ,4ʹ,5ʹ-γ-valerolactone (3,4,5-VL) was detected in 74% and 82% of lean and obese persons, respectively. Plasma AUC0–12 h for these VL metabolites did not differ by obesity status. EGC, EC, 3,4-VL, and 3,4,5-VL, but not EGCG and ECG, were primarily present in urine and urinary total VLs were increased compared with total urinary catechins. However, 24-h urinary excretion of catechins and VLs were unaffected by obesity. Conclusions Obesity reduces GTE catechin bioavailability and Cmax independent of any change in VL metabolite appearance or urinary elimination of catechins, suggesting a gut-level mechanism that limits catechin absorption. Funding Sources Supported by USDA-NIFA and the Foods for Health Discovery Theme at The Ohio State University.