Microbiota remodeling after bariatric surgery: Procedure-specific dynamics and metabolic implications

Table 1 Summary of gut microbiota remodeling after bariatric surgery and associated metabolic implications

Aspect	Roux-en-Y gastric bypass	Sleeve gastrectomy	Metabolic implications
Overall microbiota remodeling	Profound and extensive restructuring	Moderate but consistent remodeling	Contributes to sustained metabolic improvement
Dominant taxonomic shifts	Enrichment of facultative anaerobes and aero-tolerant taxa; reduction of obligate anaerobes	Enrichment of mucin-degrading and lactic acid-producing taxa	Alters microbial metabolic capacity
Microbial diversity dynamics	Often reduced early, followed by partial recovery or long-term reconfiguration	Generally stable or mildly increased over time	Diversity alone not predictive of outcomes
Bile acid-microbiota interaction	Markedly altered bile acid pools and signaling	Moderate changes in bile acid metabolism	Activation of FXR/TGR5 pathways improves glucose homeostasis
Carbohydrate metabolism	Reduced intestinal glucose absorption and altered fermentation	Improved glycemic regulation via microbial-host interaction	Enhances insulin sensitivity
Gut hormone modulation	Strong stimulation of GLP-1 and PYY secretion	Moderate incretin response	Supports appetite control and metabolic regulation
Vitamin and micronutrient handling	Greater disruption of microbial vitamin utilization	Less pronounced alterations	May contribute to postoperative deficiencies
Long-term microbiota stability	Persistent, surgery-specific microbial signatures	Relatively conserved long-term profiles	Influences durability of metabolic benefits

GLP-1: Glucagon-like peptide-1; PYY: Peptide YY.