Intestinal microbiome in normal ageing, frailty and cognition decline

Abstract

Purpose of reviewThe intestinal microbiome modulates the risk of several age-related chronic diseases and syndromes, including frailty and neurodegenerative diseases. Herein we provided an update on the influence of gut microbiota on physical and cognitive performance in older age and suggest microbiota-targeted interventions for healthy ageing. Recent findingsLow uniqueness index of the gut microbiome and high representation of Bacteroides are independently associated with mortality in older individuals, while the centenarian microbiome is characterized by high abundance of Lactobacilli and Bifidobacteria. Frailty syndrome, sarcopenia and cognitive decline are associated with reduced faecal microbiota biodiversity, reduced abundance of bacteria able to synthetize short-chain fatty acids (SCFA), including Faecalibacterium prausnitzii, and reduced faecal butyrate levels. Dietary intervention, especially involving Mediterranean diet, and exercise training seem to be associated with improved biodiversity of the microbiota, increased capacity of SCFA synthesis and, probably, protection against the onset of frailty and cognitive decline.

Probiotics: Bridging the interplay of a healthy gut and psychoneurological well‐being

“…These findings highlight the bidirectional relationship between gastrointestinal disorders and psychological well‐being, emphasizing the importance of addressing both aspects in treatment approaches. To evaluate this relationship, a clinical study by Strasser and Ticinesi (2023) assessed the effectiveness of cognitive‐behavioral therapy (CBT) in reducing both gastrointestinal symptoms and psychological distress in patients with IBS. The study found that CBT significantly improved both the severity of gastrointestinal symptoms and psychological well‐being, suggesting that addressing psychological factors can positively impact gastrointestinal disorders.…”

Dementia, infections and vaccines: 30 years of controversy

“…Nevertheless, despite the limitations of studies published heretofore, there is a consensus that patients with MCI or dementia have a different fecal microbiota composition compared to healthy controls [ 69 ]. Secondly, in most, although importantly, not all studies, AD and MCI patients exhibit reduced representation of bacterial taxa producing SCFAs, and increased representation of Bacteroidetes [ 70 , 71 ] .…”

Gut microbiota in relation to frailty and clinical outcomes

“…In this scenario, frailty has started to be an urgent concern in a soon-to-beageing society. To date, several recent studies have suggested an involvement of the gut microbiota in the pathophysiology of frailty [8,28,29] (see also Table 1). Furthermore, a cross-sectional analysis in a community-dwelling cohort of 728 female twins found that a high frailty index was associated with reduced levels of SCFA-producing microbes with anti-inflammatory properties, such as Faecalibacterium prausnitzii, and increased proportions of proinflammatory members of the Enterobacteriaceae family [30].…”

“…In this context, the debate is still open on whether changes in the gut microbiota profile during ageing (which encompasses the main factors listed earlier) are to be considered dysbiosis or vice versa adaptation to the aged condition, also considering the recent identification of potential longevity signatures in the microbiota of extremely long-lived people [7]. However, it remains a fact that particularly unbalanced gut microbial profiles can be established in the elderly, which have been associated with the onset and progression of age-related disorders, one of which is frailty syndrome [8] (Fig. 1).…”