Abstract
In recent years, a growing number of health problems have been reported in which brain dysfunction is implicated, including eating behavior disorders such as overeating and appetite loss, metabolic abnormalities such as obesity and metabolic syndrome, and mental disorders such as anxiety and depression. However, many drugs that directly act on the brain must cross the blood-brain barrier, which often leads to off-target effects and undesirable side effects. In contrast, vagal sensory nerves transmit information from peripheral organs to the brain can modulate brain function by selectively targeting specific brain regions, thereby offering the potential for regulation with minimal side effects. Food intake is one of the key factors that activate vagal sensory nerves and induces postprandial physiological responses, including the generation of satiation and the suppression of excessive rises in blood glucose levels. In this review, we focus on functional food components that activate vagal sensory nerves, specifically the rare sugar d-allulose and the amino acid γ-aminobutyric acid (GABA), and summarize their physiological functions mediated through the vagal sensory nerve-to-brain axis.
