Exploring and comparing the anti-obesity mechanisms of defatted rice bran total dietary fiber, insoluble dietary fiber, and soluble dietary fiber based on multi-omics technologies

This study aimed to investigate the anti-obesity mechanisms of rice bran total dietary fiber (RDF), rice bran insoluble DF (RIDF), and rice bran soluble DF (RSDF) from defatted rice bran. RDF, RIDF, and RSDF exhibited excellent anti-obesity effects, mainly reflected in lipid adsorption in vitro, reduction of body weight, inhibition of adipose tissue accumulation, improvement of dyslipidemia, and repair of histopathological damage. More importantly, the analysis of multi-omics results revealed that the regulation of intestinal microbiota, amino acid metabolism, and lipid metabolism were the critical pathways for the anti-obesity effects of RDF, RIDF, and RSDF. However, RIDF was involved in lipid metabolism through alanine, aspartate, and glutamate metabolism and exhibited a more favorable regulatory effect on gut microbiota. In contrast, RSDF impacted metabolic pathways dominated by tryptophan and cholesterol metabolism and excelled in immune and inflammatory amelioration. RIDF and RSDF together constitute RDF, with the latter integrating the tendencies of RIDF and RSDF in terms of intestinal microbiota and hepatic gene expression. However, RDF exhibited significant differences in metabolic regulation compared to RIDF and RSDF, particularly concerning tryptophan metabolism. These findings demonstrated that RIDF and RSDF have distinct mechanisms in obesity management, and that both contributed differently to the anti-obesity effect of RDF. This study provides experimental evidence for the development of different types of DF from defatted rice bran as personalized anti-obesity dietary supplements. It also offers new insights for future precision nutrition interventions involving DF. Defatted rice bran total dietary fiber, insoluble dietary fiber, and soluble dietary fiber have notable improvement effects on obese mice. However, their potential anti-obesity mechanisms share similarities and differences, which contributes to the advancement of personalized dietary development in the future.image