Regular Black Tea Kombucha Consumption is Associated with Improved Insulin Resistance and Increased ADIPOQ Expression in Adults with Obesity: A Pre-Post Clinical Trial

Abstract

Kombucha is a fermented beverage obtained by a Symbiotic Culture of Bacteria and Yeast (SCOBY). Although in vitro and animal studies suggest that kombucha has anti-inflammatory and anti-obesogenic properties, no clinical trials have confirmed that. In this pre-post clinical intervention study, we aimed to evaluate whether regular black tea kombucha consumption would impact metabolic, inflammatory, and oxidative stress markers; body weight and composition; and obesity-associated genes in individuals with and without obesity. This study follows the Transparent Reporting of Evaluations with Nonrandomized Designs (TREND) guidelines. Individuals with normal weight (Group 1; n=20) and with obesity (Group 2; n=16) received 200 mL of black tea kombucha for 8 weeks. Blood and subcutaneous adipose tissue (SAT) were collected at baseline (T0) and after 8 weeks of intervention (T8). Most inflammatory (hs-CRP, IFN-γ, TNF-α, and IL-4, IL-6, IL-8, IL-10, and IL-12p70) and oxidative stress markers (FRAP, MDA, and NO) showed significant changes over time following the intervention. However, interaction analyses revealed that responses to kombucha consumption differed between groups for only a limited number of variables: body weight, conicity index, HOMA-IR, and hs-CRP. An upregulation of the gene ADIPOQ in the SAT (p=0.0481) was also observed, alongside a positive correlation between BMI and PPAR (r=0.58; p=0.030), and between HOMA-IR and both NFκB (r=0.73; p=0.002) and SREBF1 (r=0.66; p=0.010). In conclusion, metabolic and inflammatory pathways may respond differently to kombucha consumption depending on obesity status. The results are mainly attributed to the high number and diversity of phenolic compounds identified in the black tea kombucha, which confer a high antioxidant capacity to the beverage.