From dysbiosis to longevity: a narrative review into the gut microbiome's impact on aging

Abstract

Aging has become an important public health concern with the accelerated aging of the global population. The rising impetus to extend lifespan as well as healthspan has drawn attention to the gut microbiome, an indispensable yet modifiable determinant of the aging process. This narrative review addresses the complex interaction between the gut microbiome and aging, synthesizing findings in logical order. Evidence from model organisms supports the causal influence of gut microbes on host aging and longevity. Developmental evolution of the human gut microbiome throughout life stages reflects its adaptive nature affected by diet, lifestyle, hormone levels, and immune function, regulating aging through the gut-muscle and the gut-brain axes in late life. Signature characteristics of the long-lived gut microbiome, including increased diversity, elevated beneficial taxa, and enhanced gut homeostasis, lead to strategies to extend longevity. Intake of fiber, regular exercise, and pro-/pre-/postbiotic supplements are potential interventions on the gut microbiome to foster vitality in later years. Centering on these connected topics, this review identifies questions warranting investigation, with potential to improve therapeutic strategies for healthy aging.

Keywords: Eubionts; Gut barrier; Gut microbiome; Gut-brain axis; Gut-muscle axis; Healthy aging; Inflammation; Longevity; Pathobionts.

Fig. 1

The human gut microbiome characteristics at different life stages. The characteristics are presented with key terms in bold typeface, following the order of compositional features, factors for modulation, and enriched metabolic function or metabolite profiles. Reconfiguration denotes the transitional stage involving the substitution of butyrate-producing taxa, where its success steers the elderly gut microbiome towards healthy aging, or vice versa, towards unhealthy aging. The icons were sourced from Flaticon.com, with credit to the following icon artists: Metami septiana, dwiangga.icon, Freepik, Eucalyp, kliwir art, mia elysia, and anilofex

Fig. 2

Mechanistical contributions of the gut microbiome to the aging process. As people age, immunosenescence occurs with a concomitant decline in gut barrier integrity and an onset of low-grade inflammation, leading to inflammaging, which contributes to gut dysbiosis then a decrease in SCFA production, further exacerbating inflammaging. The dysbiotic gut microbiome accelerates the aging process, contributing to muscle loss via the gut-muscle axis, leading to frailty, and inducing neuroinflammation through the gut-brain axis, resulting in cognitive decline. The icons were sourced from Flaticon.com, with credit to the following icon artists: Culmbio, C-mo Box, Freepik, Hat Tech, and Dewi Sari

Fig. 3

Potential interventions to modify the gut microbiome for healthy aging. The gut microbiome is largely modulated by dietary patterns, with high-fiber and Mediterranean diets showing benefits in promoting healthy aging. Moderate caloric restriction should be practiced cautiously due to the risk of muscle loss. Regular exercise with moderate intensity is also recommended. Probiotics supplementation offers beneficial effects that vary depending on heterogenous trial designs. Lastly, emerging approaches, including prebiotic and postbiotic supplementation and phage therapy, require further clinical trials to validate their safety and efficacy. The icons were sourced from Flaticon.com, with credit to the following icon artists: Culmbio, Icongeek26, Becris, Freepik, Iconjam, bsd, spacepixel, and anilofex