Effects of Probiotics and Postbiotics against Cognitive Frailty In Vivo: A Narrative Review

Abstract

Cognitive frailty (CF), a geriatric syndrome that is marked by the coexistence of frailty and cognitive impairments without the presence of dementia, increases the risk of harmful health outcomes especially amongst the older adults. Given that there remains no approved therapy that addresses CF, the continuous growth of global ageing population raises the need for non-pharmacological approach that is able to address both cognitive and physical vulnerability together rather than in isolation. There is growing evidence that positions the gut as the biological interface that influences the brain and the muscles through interconnected immune, endocrine, metabolic, and barrier-related pathways. In this context, dietary modifications using probiotics or postbiotics have gained considerable attention for their potential in attenuating processes underlying CF by reshaping gut microbial composition and function. The present review aimed at uncovering the roles probiotics and postbiotics against CF (including its individual cognitive and physical components) along with their mechanisms that are mediated through the gut-brain axis and gut-muscle axis based on the current evidence. This review featured in vivo studies on various probiotic strains and postbiotic preparations that conferred a measurable improvement in neuroprotection, memory and behavioural changes, muscle/ bone function and homeostasis, anti-/pro-inflammatory biomarkers, gut health amongst others. The consolidated evidence supports probiotics or postbiotics as supportive or adjunctive therapy to prevent or mitigate the progression of CF. More importantly, this review provides a framework to inform future translational research and rational development of targeted interventions aimed at promoting healthy ageing.