Understanding specialized biomedical knowledge can be particularly challenging, posing significant barriers to the acquisition and use of medical information especially by patients. In this study, a methodology for drafting patient-centered explanations of concepts related to the gut-brain axis and related medical conditions is proposed. The explanations are specifically intended for patients affected by neurodegenerative diseases, who are experiencing cognitive decline. The methodology consists of the following steps: 1) the drafting of specialized definitions in the form of intensional definitions, which enable the structured representation of domain-specific knowledge, and 2) the simplification of specialized definitions into patient-centered explanations. In particular, explanations intended for patients are formulated using popular terms and plain language, considered as two complementary strategies aimed at enhancing the comprehension of specialized biomedical knowledge. This work lays the foundation for the future development of a terminology resource specifically designed to collect and systematically represent knowledge related to the gut-brain axis and associated health conditions.