Tomato pectin ameliorates high-fat diet-induced hepatic lipid metabolism disorders by regulating gut microbiota

ABSTRACT Gut microbiota plays a pivotal role in protecting lipid metabolism and mitigating the risk of metabolic diseases. Bioactive dietary fibers, notably pectin, have been substantiated to exert extensive health benefits against metabolic diseases through the modification of gut microbiota. However, the mechanism underlying tomato pectin (TP)-mediated regulation of hepatic lipid metabolism and gut microbiota remains unclear. The aim of this research was to investigate the correlation between gut microbiota and metabolic adaptations observed in mice supplemented with TP while being fed a high-fat diet (HFD). The findings in our research revealed that TP supplementation alleviated hepatic steatosis and lipid metabolism disorders induced by HFD. Furthermore, TP administration increased gut microbiota diversity, promoting the abundance of beneficial bacteria (e.g., Bacteroides , Alistipes , and Alloprevotella ) while inhibiting the harmful or conditionally pathogenic bacterial populations (e.g., specific taxa within the Firmicutes phylum and Desulfobacterota ). Additionally, TP administration in HFD-fed mice improved the integrity of the intestinal barrier by maintaining the expression of tight junction proteins ( Claudin-1 , ZO-1 , Occludin ), mucins ( MUC1 ), and antimicrobial peptides ( Defb1 , Reg3 β ) compared with the HFD group. Besides, the antibiotic treatment showed an improvement in hepatic lipid metabolism disorders, and the intestinal barrier function of TP was contingent upon the gut microbiota. Overall, our findings demonstrate that TP exerts notable impacts on the gut microbiota composition in this HFD mouse model. Moreover, the improvement of hepatic steatosis and intestinal barrier function is mediated by TP-induced alterations in gut microbiota structure.