Modulation of the microbiota-gut-brain axis by bioactive food, prebiotics, and probiotics decelerates the course of Alzheimer's disease

Abstract It is evident that nowadays, the percentage of aged population is constantly increasing worldwide in the developed and nondeveloped countries. In addition, there is more evidence that aging is the main risk factor to develop Alzheimer ´s disease (AD), a neurodegenerative condition that impairs memory and cognitive performance. Among the principal pathological hallmarks for AD, are protein aggregation in the brain, which are associated with inflammation and neuronal dysfunction and currently, there are no disease-modifying drugs to prevent or cure AD. However, recent studies have explored the impact of the Mediterranean diet and bioactive food to prevent or delay the onset of dementia. Bioactive food ingestion has strong antioxidant and antiinflammatory effects, and notably, bioactive food also modulates gut microbiota (GM) composition. GM is altered in AD, and patients show a dominant proinflammatory profile compared to age-matched control subjects. It is known that ingestion of bioactive food, prebiotics, or probiotics modulates GM composition and improves cognitive scores in predemented and demented subjects. This review aims to outline the mechanism of action of bioactive food, prebiotics, and probiotics in the prevention of dementia through the modulation of the microbiota-gut-brain axis. We provide documented evidence that bioactive food, an accessible diet with minimal side effects, can decelerate the rate of neurodegeneration in the aging population.