Recently, safety concerns have been raised about the use of A. municiphila as a probiotic, as its enrichment in neurodegenerative diseases (e.g., Alzheimer’s disease, multiple sclerosis) could contribute to the progression of neural pathologies by degrading mucin, increasing gut inflammation and permeability and finally leading to higher endotoxaemia, and systemic inflammation33,49. Here, MUC5AC is linked to Alzheimer disease.