The impact of gut microbiome modulation on anthropometric indices in metabolic syndrome: an umbrella review

Background: Metabolic syndrome (MetS) is a complex disorder characterized by a cluster of metabolic risk factors. Recent research highlights the gut microbiome's role in metabolic regulation, suggesting that modulation through probiotics, prebiotics, and synbiotics may provide a novel approach to managing MetS. This umbrella review aims to integrate insights from existing meta-analyses to explore how changes in gut microbiota influence key body measurement indicators in individuals with MetS. Methods: A systematic search of PubMed, Scopus, and Web of Science databases identified meta-analyses that assessed the impact of probiotics, prebiotics, or synbiotics on anthropometric indices in MetS patients. Results: The results indicated that microbial therapy leads to a significant reduction in body mass index (BMI) (SMD: -0.22; 95% CI: -0.35 to -0.09; P < 0.01) and waist circumference (WC) (SMD: -0.47; 95% CI: -0.80 to -0.15; P < 0.01). However, microbial therapy did not significantly affect body fat mass (SMD: -0.30; 95% CI: -0.64 to 0.02; P = 0.06), body fat percentage (SMD: -0.29; 95% CI: -0.62 to 0.03; P = 0.07), waist-to-hip ratio (SMD: -0.09; 95% CI: -0.46 to 0.28; P = 0.63), and weight (SMD: -0.06; 95% CI: -0.21 to 0.08; P = 0.37). Conclusions: Gut microbial modulation, mainly through probiotics and synbiotics, shows promise in reducing BMI and WC in MetS patients. However, its effects on other anthropometric indices remain uncertain, warranting further high-quality research to fully understand microbial interventions' therapeutic potential.