Unveiling the neuroprotective impact of virgin olive oil ingestion via the microbiota–gut–brain axis

The gut–brain axis, a complex system of two-way communication between both organs, plays a key role in overall health. This comprehensive review explores the possible neuromodulatory effects upon consumption of virgin olive oil (VOO) via changes in the gut microbiota. The components found in VOO, such as polyphenols and monounsaturated fatty acids, and their function in influencing the composition of the gut microbiota, focusing on those known to possess neuroactive characteristics, based on a thorough analysis of the literature were investigated. Studies suggest that these compounds, such as hydroxytyrosol and ferulic acid, may protect against neuronal death and inhibit amyloid-β plaques (Aβ) formation. Furthermore, preclinical and clinical research indicates that VOO may promote the growth of beneficial bacteria, such as Lactobacillus and Bifidobacterium, and increase the production of short-chain fatty acids (SCFAs). These changes could be related to improved cognitive function, mood regulation, and neuroprotection. However, limitations of these studies (short duration of studies, the variability in VOO composition and the lack of standardized methodologies) need to be overcome. Furthermore, the limited number of human trials and incomplete understanding of the gut–brain axis make it difficult to establish causality and clinical application of the findings. For this reason, future research should focus on long-term clinical trials with larger cohorts, standardised characterisation of VOO and on exploring the synergistic effects with other dietary components. Furthermore, mechanistic studies should aim to uncover the molecular pathways involved in the gut–brain axis to develop specific dietary interventions for neurological and neurodegenerative disorders.