Gut health and microbiome modulation by the heat-killed postbiotic beLP1® in adults with excess weight: a randomized, placebo-controlled trial

Background Overweight is linked to gut microbiota dysbiosis and gastrointestinal (GI) symptoms that impair quality of life. Methods This 84-day randomized, double-blind, placebo-controlled study evaluated the gut-health effects of heat-killed Lactiplantibacillus plantarum (beLP1 ® ) in otherwise healthy adults (aged 18–45 years) within the BMI range of 25–35 kg/m 2 and a ≥3-month history of mild-to-moderate GI discomfort, confirmed by Gastrointestinal Symptom Rating Scale (GSRS). In this trail 140 adults were allocated in a 1:1 ratio to receive either daily beLP1 ® (>30 billion cells) ( n = 70) or placebo ( n = 70). A total of 103 participants completed the study without protocol deviations and were included in the primary per-protocol (PP) analysis (beLP1 ® : n = 49; Placebo: n = 54). This predefined analysis directly compares the beLP1 ® and placebo arms using analysis of covariance (ANCOVA), supplemented by two independent-sample Student’s t -tests. The primary endpoint was change in gastrointestinal symptoms via the GSRS, secondary endpoints included the Perceived Stress Scale (PSS), the Digestion-associated Quality of Life Questionnaire (DQLQ), Tumor Necrosis Factor-alpha (TNF-α), lipid parameters, Dual-Energy X-ray Absorptiometry (DEXA), and gut microbiome diversity by metagenomic Next-Generation Sequencing (NGS). Results Compared to placebo, beLP1 ® significantly reduced total Gastrointestinal Symptom Rating Scale (GSRS) scores at Day 42 ( p = 0.0215) and Day 84 ( p = 0.0394), with prominent improvements in abdominal pain ( p = 0.0205) and dyspeptic syndrome ( p = 0.0303) domains. Significant reductions in perceived stress ( p = 0.0004) and improvements in digestion-associated quality of life ( p = 0.0008) were concurrently achieved. Metagenomic analysis revealed a favorable modulation of the gut microbiota, characterized by an enrichment of several short-chain fatty acid-producing bacteria and a significant reduction in multiple opportunistic pathogens. No significant changes occurred in serum TNF-α, lipid profiles, or DEXA body composition metrics. Conclusion Overall, beLP1 ® safely and progressively alleviates GI symptoms, reduces stress, and optimizes microbiome composition in adults with excess weight. ClinicalTrials.gov: NCT05820737. Clinical trial registration https://clinicaltrials.gov/study/NCT05820737?cond=NCT05820 , identifier NCT05820737.