The role of microbiota modulation in preventing Alzheimer's disease- a review.

Alzheimer’s disease (AD) is the most common form of dementia, and its incidence is projected to triple worldwide over the next 25 years. The most prevalent form, late-onset Alzheimer’s disease (LOAD), develops in genetically predisposed individuals exposed to environmental risk factors. Hallmarks of AD include accumulation of amyloid-β (Aβ), neurofibrillary tangles (NFTs), neuroinflammation, and mitochondrial dysfunction, resulting in oxidative stress, impaired glucose metabolism, and cognitive decline. Such metabolic disruptions result in early cerebral glucose hypometabolism and other metabolic disruptions, including altered lipid and branched-chain amino acid profiles. Recent evidence suggests that gut microbiota alterations, although individually variable, are a consistent and influential factor in AD progression via inflammatory and metabolic pathways. This narrative review explores therapeutic interventions targeting the gut-brain axis, including fecal microbiota transplantation (FMT), probiotic and antibiotic treatments, and dietary strategies such as the ketogenic and Mediterranean diets, as well as nutritional compounds such as omega-3 fatty acids. The aim is to evaluate the latest findings in both preclinical and clinical studies to identify multi-targeted, microbiota-based approaches for the prevention and management of AD.