A Green Tea Extract-Rich Confection in Healthy and Metabolic Syndrome Adults Decreases Small Intestinal Permeability in Association With Lower Gut Inflammation

Abstract Objectives Poor gut health, including increased intestinal permeability and inflammation, enhances cardiometabolic risk. Catechin-rich green tea extract (GTE) alleviates cardiometabolic complications in obese rodents by limiting gut permeability and inflammation, but whether these benefits occur in humans is not known. We hypothesized that the anti-inflammatory activities of GTE would decrease gut barrier dysfunction in persons at heightened cardiometabolic risk. Methods In a randomized, double-blind, placebo-controlled crossover study, persons with metabolic syndrome (MetS) and healthy persons completed two 4-wk interventions in which they received placebo or GTE confections (890 mg/d total catechins) while following a low-polyphenol diet. At wk 4, participants provided fecal samples for ELISA-based measures of inflammatory proteins. 24-h urine samples were also collected for LC/MS analysis of non-digestible sugars following the ingestion of lactulose (LAC), mannitol (MAN), sucralose (SUC), and erythritol (ERY). Data were analyzed by repeated measures ANOVA and linear regression controlling for within-subject repeated measures. Results MetS (n = 21; 40 ± 3 y; 35.2 ± 1.0 kg/m2) and healthy (n = 19; 34 ± 2 y; BMI = 22.3 ± 0.4 kg/m2) adults completed the study with no adverse effects, no changes in liver function tests, and > 95% compliance based on returned confections. Urinary SUC/ERY was unaffected by GTE and health status, but urinary LAC/MAN was lower (P = 0.043) in GTE compared with placebo regardless of health status. Fecal myeloperoxidase and calprotectin did not differ by health status, but were lower (P = 0.03–0.05) in response to GTE regardless of health status, and were positively correlated with each other (r = 0.75; P < 0.001). Fecal calprotectin and myeloperoxidase were both positively correlated with LAC/MAN ratio (r = 0.39–0.42; P = 0.01–0.02). Conclusions Interim findings of this study support that dietary GTE decreases small intestinal permeability in association with lower gut inflammation, which may help to explain its known cardiometabolic benefits. Funding Sources USDA-NIFA (2019–67,017-29,259), USDA-HATCH, and the Ohio Agricultural Research and Development Center at The Ohio State University.