Dietary Carbohydrates and the Intestinal Barrier: Emerging Insights into NF-κB Modulation and Health Outcomes

The intestinal barrier is essential for maintaining mucosal homeostasis, and its dysfunction, often mediated by aberrant nuclear factor-kappa B (NF-κB) activation, is closely linked to chronic inflammation. Dietary carbohydrates modulate this barrier primarily through microbial fermentation and metabolite-mediated signaling. This review synthesized current evidence on how carbohydrate structure, including degree of polymerization, branching, and chemical modifications, influenced gut microbiota, short-chain fatty acid (SCFAs) production, and NF-κB regulation. Interestingly, glycemic carbohydrates promote barrier disruption and chronic inflammation by enhancing NF-κB activation, while nonglycemic carbohydrates such as oligosaccharides, fibers, and resistant starch strengthen the gut barrier and suppress inflammatory pathways through beneficial microbiota shifts and SCFAs production. Mechanistic insights are supported by both preclinical and emerging clinical data, although human evidence remains limited and heterogeneous in the dose–response and population outcomes. The review also highlights recent advances in carbohydrate engineering, which show promise for precision modulation of the carbohydrate–microbial metabolites–NF-κB–barrier axis. Future research directions are outlined, including the development of functional carbohydrates tailored for personalized nutrition and techno-functional hybrids. These findings support dietary strategies and functional food innovations targeting carbohydrate structure to optimize gut health and reduce inflammation-driven diseases through the precise regulation of NF-κB signaling pathways.