Nutraceuticals and the Microbiota–Gut–Brain Axis: A Pathway for Preventing Cognitive Decline

With the global rise in aging populations, cognitive impairment and neurodegenerative diseases, such as Alzheimer's disease (AD), present a growing public health issue. Current pharmacological treatments primarily target symptoms rather than underlying causes, necessitating the exploration of alternative preventive strategies. Nutraceuticals have emerged as promising candidates for neuroprotection due to their ability to modulate oxidative stress, neuroinflammation, and mitochondrial function. This narrative review aimed to evaluate the neuroprotective potential of nutraceuticals and their interactions with the microbiota-gut-brain axis in preventing age-related cognitive decline. A comprehensive search of the scientific literature using the PubMed, Scopus, and Web of Science databases was undertaken, focusing on publications during the period 2010-2025. Nutraceuticals, including vitamins, omega-3 fatty acids, coenzyme Q10, polyphenols, and isothiocyanates, exhibit neuroprotective properties through antioxidant, anti-inflammatory, and mitochondrial-support mechanisms. The gut microbiota plays a crucial role in regulating the bioavailability and efficacy of these compounds. Microbiome-based interventions, such as prebiotics, probiotics, and fecal microbiota transplantation demonstrate potential in modulating neuroinflammatory responses and supporting cognitive function. Nutraceutical and microbiome-targeted interventions represent promising, low-risk strategies for preventing cognitive decline. Their ability to modulate neuroinflammation and oxidative stress underscores their potential for future clinical applications. Further large-scale studies are needed to validate their efficacy and explore personalized approaches adapted to individual microbiome profiles.