Short-chain fatty acids, on the other hand, improve hippocampal neuroprotection and plasticity and reduce Aβ plaques in AD models by activating G protein-coupled receptors (GPCRs) to stimulate enteroendocrine L cells to release glucagon-like peptide-1 (GLP-1) (Dalile et al., 2019). Here, GCG is linked to Alzheimer disease.