Impact of Citrus Pectin on Gut Microbiota Metabolism Dysbiosis Induced by Transient Alternating High-Fat Diet

Pectin, as an important component of dietary fiber, plays a crucial regulatory role in maintaining the homeostasis of gut microbiota. The transient alternate high-fat diet (TAHD) is a dietary pattern that alternates between 3 days of a low-fat diet (LFD) and 3 days of a high-fat diet, aiming to simulate daily dietary habits. In this study, we investigated the temporal dynamics of gut microbiota and short-chain fatty acids (SCFAs) in response to citrus pectin (CP, 3% (w/w)) supplementation under TAHD. CP effectively reduced the abundance of the phylum Bacillota and promoted the phylum Bacteroidota. During the LFD phase, CP significantly increased Faecalibaculum_rodentium colonization abundance (3.76-fold within 1 day; P < 0.05) and promoted SCFA biosynthesis. In addition, the synergistic intervention of CP enhanced the thermogenic metabolism of the host by activating the mRNA expression levels of thermogenesis-related genes (such as UCP1, etc.) in brown adipose tissue. This series of studies systematically elucidated the molecular mechanism by which CP improves host metabolic homeostasis by optimizing the structure of the gut microbiota from the perspective of the microbiome-metabolism axis, providing an important theoretical basis for the application of dietary fiber in the prevention and treatment of metabolic diseases.