Modified Coconut Pomace Insoluble Dietary Fiber Ameliorates Hyperglycemia via Gut Microbiota–Derived Butyrate and AMPK Activation in Type 2 Diabetes Rats

Abstract Dietary interventions for type 2 diabetes (T2DM) remain challenging. Insoluble dietary fiber (IDF) has gained attention for modulating gut microbiota and metabolic homeostasis. This study investigated the hypoglycemic effects of coconut pomace IDF before and after modification by ultrafine grinding combined with plasma-activated water treatment in a T2DM rat model. Modified coconut pomace fiber (UPCPF) ameliorated hyperglycemia, improved insulin sensitivity, and alleviated hepatic metabolic dysfunction. These effects were associated with remodeling of gut microbiota, particularly enrichment of Akkermansia and butyrate-producing bacteria, with increased fecal butyrate. Consistently, the expression of intestinal FFAR2, GCG, and PCSK1 was upregulated, resulting in enhanced GLP-1 secretion. Further analyses indicated AMPK activation, suppressed gluconeogenesis, and improved lipid metabolism. These findings indicate that UPCPF exerts metabolic benefits through modulation of the gut microbiota, increased butyrate production, and activation of AMPK signaling, providing a theoretical basis for the application of modified dietary fiber in metabolic disease management.