Gut sensing of food ingredients and interoception-mediated regulation of feeding and glucose metabolism.

Food intake not only provides pleasure through exteroceptive sensations such as taste and smell but also elicits beneficial physiological effects via interoceptive signals arising from the gastrointestinal tract and beyond. Among these interoceptive pathways, vagal sensory (vagal afferent) nerves play a central role in transmitting food-derived information to the brain. This review first outlines the anatomical and functional characteristics of vagal sensory nerves. It then examines how food-related signals, including mechanical stretching of the gastrointestinal wall, gastrointestinal and pancreatic hormones such as glucagon-like peptide-1, and microbial metabolites like short-chain fatty acids, are detected by vagal pathways. These inputs collectively regulate food intake, nutrient preferences, and systemic metabolism. Recent studies further suggest that vagal sensory nerves enable the brain to anticipate and adapt to the metabolic demands of food intake, serving as a key mechanism for maintaining homeostasis during rapid postprandial changes. Understanding the role of vagal afferents in sensing meal-derived signals and mediating gut-brain communication provides insights into how interoceptive pathways orchestrate energy balance and hold promise for developing therapeutic strategies for metabolic disorders such as obesity and diabetes.