Foodborne Carbon Dots Trigger Appetite Suppression: Mechanistic Insights from the Microbiota-Gut-Brain Axis

Foodborne carbon dots (FCDs) are an overlooked ingestible nanoscale food substance, and the potential ingestion risks associated with persistent dietary preferences need to be clearly articulated. In this study, the effects of FCDs and glucose CDs on feeding behavior in mice were elucidated from the perspectives of gut microbiome, metabolic flow monitoring, and metabolomics. The results demonstrated that persistent intake of FCDs (25 mg/kg/day) for 30 days significantly caused diminished appetite. Mechanistic findings suggested that FCDs were involved in the regulation of appetite reduction through the microbiota-gut-brain axis. FCDs induce perturbations in the gut microbiota, leading to increased levels of intestinal inflammation. In addition, the intake of FCDs was directly involved in microbial metabolism to generate SCFAs, activate intestinal GPR-41/43, promote the release of glucagon-like peptide, and further stimulate the hypothalamus to significantly downregulate the expression of AGRP and upregulate the expression of POMC, ultimately leading to the reduction of appetite. Moreover, intake of FCDs regulates intestinal fatty acid metabolism, amino acid metabolism, and other factors affecting the level of health of the organism. The present work highlights the impact of dietary intake of source FCDs on ingestion, providing unique perspectives on the potential health threats of FCDs.