Pectic oligosaccharides reshape the gut microbiota-mediated intestinal vitamin B7 metabolic network to alleviate metabolic dysfunction-associated steatotic liver disease.

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a prevalent and severe global health burden closely associated with gut dysbiosis and systemic metabolic disorders. Pectic oligosaccharides (POS) are functional prebiotics with metabolic regulatory potential, yet their exact efficacy and microecological mechanisms against MASLD via the gut-liver axis are still unclear. In this study, multi-omics profiling of HFD-induced MASLD mice revealed that POS alleviates hepatic steatosis and improves lipid metabolism by enriching a core microbiota dominated by Phocaeicola dorei and reactivating its de novo vitamin B7 biosynthesis. Importantly, leveraging serum metabolomics from an external human MASLD cohort, we confirmed a severe systemic deficiency of VB7 and its precursors that strongly correlated with fasting glucose, insulin resistance, and hepatic injury. In summary, this study identified POS as an effective intervention to alleviate MASLD by restoring intestinal endogenous VB7 supply, providing a strong rationale for developing POS as a therapeutic prebiotic.