Young at gut: How to modulate the microbiome for healthy ageing?

At the Microbiome Summit 2026, experts shared insights into how the gut microbiome can be modulated to support healthy ageing.

Gut microbiome in healthy vs unhealthy ageing

Young healthy adults have a relatively thick intestinal mucus layer and a core microbiome dominated by mucus-degrading Bacteroides. [Nat Aging 2022;2:869-871]

“Progressive thinning of the gut mucosal layer occurs in both healthy and unhealthy ageing. In healthy ageing and longevity, there is progressive loss of the Bacteroides-dominant core microbiota, accompanied by acquisition of a longevity-adapted subdominant fraction,” explained Professor Francis Chan of the Microbiota I-Centre (MagIC) and Department of Medicine & Therapeutics, Chinese University of Hong Kong (CUHK). [Nat Aging 2022;2:869-871; Curr Biol 2016;26:1480-1485]

In unhealthy older adults, the Bacteroides-dominant core taxa is retained, which contributes to increased inflammation, reduced intestinal barrier integrity, and disrupted immune cell function. [Nat Aging 2022;2:869-871; Genes Immun 2021;22:289-303] “Passage of harmful bacteria and their toxic metabolites through the impaired intestinal barrier may lead to central nervous system inflammation,” said Chan.

Can FMT reverse ageing?

“Faecal microbiota transplantation [FMT] from young mice to old mice, and from humans to mice, is shown to improve surrogate markers of healthy gut microbiome or reduce surrogate markers of ageing,” said Chan. [hLife 2023;1:8-11] “Ongoing studies in humans are exploring if genetic manipulation of unhealthy gut microbiome and the use of so-called antiageing agents, such as bile acids and short-chain fatty acids [SCFAs], can reverse the ageing process.” [iMetaOmics 2024;doi:10.1002/imo2.36]

“However, FMT from young to old individuals may not be a good thing. Putting a lot of Bacteroides into the elderly, particularly those who are unhealthy, may cause further damage to the already-thin gut mucosal layer,” he suggested.

How about diet and supplements?

“Diet is very important. It is shown to correct dysbiosis and contributes to healthy ageing,” said Chan. “The Mediterranean diet, for example, is a source of antiageing superfoods.”

“The high-fibre Mediterranean diet is rich in SCFAs and other metabolites that cross-feed other microbial populations in the gut to support stability of microbiome function. This stability is important for resilience against perturbations, including those associated with age-related diseases,” said Professor Eugene Chang of the Department of Medicine and Microbiome Medicine Programme, University of Chicago, US. [Nature 2025;642:747-755]

Prof Francis Chan (left), Prof Eugene Chang (right)

Soy intake also plays a role. A Japanese cross-sectional study in older community residents of the “longevity city”, Kyotango, showed significantly higher intake of soy and soy products in nonfrail vs frail individuals. [J Clin Biochem Nutr 2024;75:161-173]

“However, there are insufficient scientific data to support the use of prebiotics, probiotics, postbiotics, senolytics or senomorphics to reverse ageing,” said Chan.

Early life: Most important window of opportunity

“The gut microbiome during the first 2–3 years of life is the most important. Healthy ageing is very likely if we can manipulate and maintain a healthy early-life gut microbiome,” said Chan.

CUHK’s ongoing prospective longitudinal MOMmy study, initiated in 2019, evaluates how early-life microbiome can be manipulated to improve subsequent health through tracking of serial biological samples and clinical metadata from parents and their children in Hong Kong and mainland China. “Recent results showed delayed gut microbial maturation and a 46 percent increased incidence of atopic diseases in infants born during vs before the COVID-19 pandemic,” said Chan. [Gut Microbes 2025;17:2443117]