Gerobiotics and neuroprotection: effects on the gut-brain axis in age-related neurodegenerative diseases.

As the global population ages, effective strategies to attenuate or prevent neurodegenerative processes are becoming increasingly important. Gerobiotics, an emerging class of probiotic strains and their derived postbiotics, are considered promising geroprotective agents because of their potential to target fundamental mechanisms of aging, modulate the gut-brain axis, and attenuate age-related cognitive and functional decline. This review aims to synthesize existing evidence from preclinical and clinical studies on the neuroprotective effects of gerobiotics, with particular emphasis on ageing-related changes in gut microbiota composition, systemic inflammation, and the pathophysiology of neurodegenerative diseases. Preclinical animal studies show that gerobiotics ameliorate memory impairment, preserve synaptic integrity, and attenuate neuroinflammation. Furthermore, clinical results suggest improvements in cognitive performance, mood regulation, and gastrointestinal function, particularly in the early stages of neurodegenerative disorders and among individuals with mild cognitive impairment. The microbiota-gut-brain axis has emerged as a relevant therapeutic target, with gerobiotic supplementation representing a multidimensional approach to support healthy cognitive ageing and counteract neurodegenerative processes. The underlying mechanisms, manifested mostly through modulation of microbial metabolites, include the restoration of intestinal and blood-brain barrier integrity, the reduction of neuroinflammation, the enhancement of neurotrophic factors, and the modulation of immunological pathways. Although current evidence is promising, heterogeneity in probiotic strains, dosages, and study designs indicates the need for further rigorous investigation. Further well-designed, large-scale clinical studies are required to establish efficacy, optimize intervention protocols, and support the translation of gerobiotics into evidence-based clinical practice for the prevention and management of age-related neurodegenerative diseases.