Integrated Gut Microbiota and Metabolomic Profiling Reveals Key Associations between Amino Acid Levels and Gut Microbial Composition in Patients with Obesity

Qi MusenWang Li^*

• Liaoning University of Traditional Chinese Medicine, Shenyang, China

Introduction: Obesity is an increasingly serious global health concern and is closely associated with gut dysbiosis and metabolic imbalance. Despite the considerable research conducted on the gut microbiota and metabolism over recent years, studies focusing on their correlation with obesity remain limited. In this study, we sought to characterize the gut microbiota and serum metabolic profiles of patients with obesity, aiming to identify potential biomarkers and therapeutic targets for this condition, and explore possible links between altered amino acid levels and gut microbial composition in its pathophysiology. The findings may offer novel insights into obesity prevention and treatment through microbiota modulation or amino acid regulation. Results: Significant differences in microbial composition were observed across multiple taxonomic levels between the controls and patients with obesity. At the phylum level, Proteobacteria was enriched in the obesity group. At the class level, Gammaproteobacteria and Erysipelotrichia were found to be enriched in obesity. At the order level, enrichment was observed for Enterobacteriales and Erysipelotrichia . At the family level, Enterobacteriaceae showed enrichment in obesity. Finally, at the genus level, Escherichia-Shigella was enriched in obesity, while at the species level, Bacteroides fragilis and Parabacteroides distasonis were noted to be enriched. Metabolomic analysis revealed that in patients with obesity, the abundance of carnosine , creatinine , and cystine was significantly increased compared with that in the controls; in contrast, that of ornithine , citrulline , glycine , and serine was significantly decreased. This suggested that these metabolites may have potential as early diagnostic biomarkers for obesity. Conclusions: Obesity is associated with coordinated shifts in specific gut taxa and serum metabolites, with measurable effect sizes and strong discriminatory performance. Modulating amino acid levels or gut microbiota composition may represent a promising strategy for obesity prevention and treatment.