BACKGROUND: Current pharmacological treatments for metabolic dysfunction-associated steatotic liver disease (MASLD) are often accompanied by adverse side effects. Consequently, probiotics, prebiotics, and synbiotics, which are bioactive compounds from fermented foods and offer fewer side effects, have garnered significant attention as alternative therapeutic strategies. OBJECTIVE: This study aims to assess the efficacy of microbial therapies-probiotics, prebiotics, and synbiotics-in managing MASLD and to identify the optimal treatment modality for various clinical indicators through a comprehensive umbrella review of meta-analyses. METHODS: A thorough literature search was conducted across PubMed, Web of Science, EMBASE, Cochrane Library, and Scopus to identify 23 meta-analyses over 18,999 MASLD patients as of November 2024. RESULTS: The findings indicate that microbial treatments positively influence levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), homeostasis model assessment of insulin resistance (HOMA-IR), insulin, tumour necrosis factor-alpha (TNF-α), C-reactive protein (CRP), and body mass index (BMI) in MASLD patients. Notably, probiotics were most effective in reducing TC, ALT, AST, GGT, insulin, TNF-α, and BMI
prebiotics were most effective in reducing TG
and synbiotics were most effective in reducing LDL-C, HOMA-IR, and CRP. CONCLUSION: Our study provides robust evidence for microbial treatments of MASLD, enabling targeted interventions for different indicators.