By Dr. Liji Thomas, MD Reviewed by Lauren Hardaker Apr 1 2026 From Mediterranean diets to probiotics, scientists reveal how reshaping the gut microbiome could help protect brain function, while highlighting why timing may be critical for slowing cognitive decline.  Study: The association between gut microbiota and cognitive decline: A systematic review of the literature. Image credit: Toa55/Shutterstock.com The gut-brain axis is gaining importance as a modulator of brain functional health. A