A taxonomy-based putative butyrate-producing gut bacteria profile was associated with better admission muscle health in older post-stroke rehabilitation patients, supporting a gut-muscle phenotype association but not microbial function or causality.
Key Findings
Results
A higher putative butyrate-producing gut bacteria profile was associated with greater handgrip strength in older post-stroke patients after adjustment for confounders.
β = 1.85 kg, 95% CI 0.61–3.09
Models adjusted for age, sex, comorbidity, premorbid function, nutritional risk, and inflammation
Study included 136 patients with mean age 78.7 years, 55.1% men
The six-genera profile was constructed using genus-level relative abundance with centered log-ratio transformation, standardization, and averaging
Results
A higher putative butyrate-producing gut bacteria profile was associated with greater skeletal muscle mass index (SMI) after adjustment.
β = 0.30 kg/m², 95% CI 0.07–0.54
SMI was one of four muscle health outcomes assessed
All models adjusted for age, sex, comorbidity, premorbid function, nutritional risk, and inflammation
Results
A higher putative butyrate-producing gut bacteria profile was associated with greater BMI-indexed appendicular skeletal muscle mass (ASM/BMI) after adjustment.
β = 0.04, 95% CI 0.01–0.07
ASM/BMI was assessed alongside handgrip strength and SMI as a muscle health outcome
Registry-based cross-sectional study design was used
Results
A higher putative butyrate-producing gut bacteria profile was associated with lower prevalence of sarcopenia.
Prevalence ratio 0.81 per standard deviation, 95% CI 0.71–0.93
Sarcopenia was defined by Asian Working Group for Sarcopenia 2025 criteria
80 of 136 patients (58.8%) had sarcopenia at admission
Patients with systemic antibiotic exposure within 4 weeks before stool sampling were excluded
Results
At the genus level, the strongest exploratory signals for the gut-muscle association were observed for Agathobacter and Butyricicoccus.
These genus-level findings were described as exploratory
The overall profile comprised six genera constructed from 16S rRNA gut microbiota data
The authors caution that these findings support a phenotype association, not microbial function or causality
Methods
The study population consisted of older post-stroke rehabilitation patients with a high prevalence of sarcopenia.
136 patients aged 65 years or older were included
Mean age was 78.7 years; 55.1% were men
58.8% (80/136) had sarcopenia by AWGS 2025 criteria
Patients were required to have 16S rRNA gut microbiota data and no systemic antibiotic exposure within 4 weeks before stool sampling
The study used a registry-based cross-sectional design
What This Means
This research examined whether the types of bacteria living in the gut — specifically those thought to produce a substance called butyrate — were linked to muscle health in older adults recovering from stroke. The study looked at 136 patients with an average age of nearly 79 years admitted for stroke rehabilitation. Researchers measured muscle strength (handgrip), muscle mass, and whether patients had sarcopenia (a condition of low muscle mass and strength common in older adults). They found that patients with a higher abundance of putative butyrate-producing gut bacteria had stronger grip strength, more muscle mass, and lower rates of sarcopenia, even after accounting for factors like age, nutrition, and inflammation. Nearly 59% of the patients had sarcopenia, highlighting how common muscle loss is in this vulnerable population.
Butyrate is a short-chain fatty acid produced when certain gut bacteria ferment dietary fiber, and it has been linked in other research to various health benefits including potential effects on muscle tissue. Two specific bacterial genera — Agathobacter and Butyricicoccus — showed the most notable associations with muscle health in exploratory analyses. However, the authors are careful to note that because this was a cross-sectional study (a snapshot in time), it cannot prove that these bacteria cause better muscle health; it only shows that the two are associated.
This research suggests there may be a connection between the gut microbiome and muscle health in older stroke patients — sometimes called a 'gut-muscle axis.' If future studies confirm this relationship, it could open doors to investigating whether dietary changes or probiotics that promote butyrate-producing bacteria might support muscle health in this vulnerable population. For now, the findings highlight an area worth further investigation but should not be interpreted as a clinical recommendation.
Yoshimura Y, Matsumoto A, Shimazu S, Yoneda K, Nagano F, Wakabayashi H, et al.. (2026). Putative Butyrate-Producing Gut Bacteria Profile and Muscle Health in Older Post-Stroke Patients.. Geriatrics & gerontology international. https://doi.org/10.1111/ggi.70869