Amelioration on the glycolipid metabolism by short-chain inulin-fortified rice flour is mediated via gut microbiota remodeling with enhanced colonic fermentation and SCFA production.

The high glycemic index and rapid digestibility of refined rice flour pose challenges for blood glucose management, particularly for individuals with diabetes. This study investigated the efficacy of inulin-fortified rice flour in improving glycolipid metabolism in diabetic mice and elucidated the underlying mechanisms. Inulin with varying degrees of polymerization (DP) was screened using in vitro starch digestion and fecal fermentation, and the optimal formulation was then evaluated in db/db diabetic mice and normal mice. Supplementation with 10% short-chain inulin (SI; DP ≤ 10) significantly reduced the starch hydrolysis rate and estimated glycemic index (eGI) by 19.4% and 15.1%, respectively. In an 8-week animal study, diabetic mice fed the SI-fortified rice flour diet exhibited improved fasting blood glucose levels, enhanced glucose tolerance, and reduced dyslipidemia. Histopathology confirmed the alleviation of hepatic steatosis and pancreatic islet injury. Mechanistically, SI remodeled gut microbiota by enriching Muribaculaceae, Lactobacillus, and the butyrate-producing family Lachnospiraceae, while decreasing the Firmicutes-to-Bacteroidetes ratio. Consistently, SI markedly elevated cecal acetate and propionate concentrations by 45.9% and 55.2%, respectively. Collectively, short-chain inulin-fortified rice flour effectively alleviates glucose and lipid metabolic disorders, at least partially, by synergistically modulating gut microbiota composition and boosting short-chain fatty acid production. This presents a viable strategy for designing precision nutritional staple foods tailored to diabetic populations.