In the case of an intestinal flora imbalance [123], these mechanisms could be mediated by cytokines or certain chemicals such as gastrointestinal hormones (e.g., CCK), neurotransmitters (e.g., 5-HT), or the secretion of metabolites (e.g., from short-chain fatty acids), causing autonomic nervous system disorders and leaky gut syndrome, ultimately leading to long-term neurological disorders [124]. Here, CCK is linked to nervous system disorder.