Tier 2 — strong

Gut barrier and microbiota changes with glycine and branched-chain amino acid supplementation in chronic haemodialysis patients

Genton L, Pruijm M, Teta D, Bassi I, Cani PD, Gaïa N, Herrmann FR, Marangon N, Mareschal J, Muccioli GG, Stoermann C, Suriano F, Wurzner-Ghajarzadeh A, Lazarevic V, Schrenzel J
Journal of cachexia, sarcopenia and muscle 2021 12(6):1527-1539

Bibliography

PubMed
PMID 34535959
PubMed Central
PMC8718035
DOI
10.1002/jcsm.12781
Trial registry
View on ClinicalTrials.gov Registered trial — results not yet published in a peer-reviewed journal.
Funding
Swiss National Science Foundation, Alfred and Alice Lachmann Foundation and Fresenius Kabi Deutschland; additional FNRS support is listed in the source.
Competing interests
Reported relationships include nutrition/renal-industry grants, fees and travel support, plus microbiome-company cofounding and patents for certain investigators.

Study snapshot

DesignMulticenter randomized double-blind crossover trial; gut-barrier and microbiota report
ModelAdult humans
Sample37 randomized; 36 started and had baseline measurements; 27 compliant completers in the per-protocol analysis
InterventionGlycine 14 g/day (7 g twice daily) versus BCAA 14 g/day in malnourished hemodialysis patients
DurationTwo 4-month supplementation periods separated by a 1-month washout; 9 months total
EndpointsGut permeability; Cytokines and appetite mediators; Fecal microbiota; Fecal IgA

What the study showed, in plain terms

This companion publication examines gut and inflammatory outcomes from the same dialysis nutrition study. It did not find broad improvements in the measured gut-barrier or cytokine outcomes.

Key findings

  • Neither supplement established improvement in circulating cytokines, appetite mediators, intestinal permeability, endocannabinoids or fecal IgA.
  • Overall microbiota composition and diversity remained stable.
  • The decreases in Lacticaseibacillus paracasei and Bifidobacterium dentium occurred during BCAA supplementation; they are not evidence of a glycine-induced microbiome benefit.

What this study can and cannot tell us

Shares participants with the fat-free-mass report; it is not a second independent trial.

Small compliant-completer analysis in dialysis cannot establish gut benefits for healthy adults.

Related papers in the corpus

Tier 2
The effect of enteral glycine on plasma glycine and muscle structure, size, and function in the critically ill: A randomized controlled trial
Ali Abdelhamid Y et al. · Clinical nutrition (Edinburgh, Scotland) · 2025
Tier 2
Glycine increases fat-free mass in malnourished haemodialysis patients: a randomized double-blind crossover trial
Genton L et al. · Journal of cachexia, sarcopenia and muscle · 2021
Tier 2
The effect of arginine or glycine supplementation on gastrointestinal function, muscle injury, serum amino acid concentrations and performance during a marathon run
Buchman AL et al. · International journal of sports medicine · 1999
Tier 4
An Update of the Promise of Glycine Supplementation for Enhancing Physical Performance and Recovery
Ramos-Jiménez A et al. · Sports (Basel, Switzerland) · 2024
Tier 3
High-Intensity Interval Training Combined with Glycine Supplementation Drives Ferroptosis Resistance to Counteract Skeletal Muscle Atrophy in Aging Mice
Ni PS et al. · Medicine and science in sports and exercise · 2025
Tier 2
The effect of glycine administration on the characteristics of physiological systems in human adults: A systematic review
Soh J et al. · GeroScience · 2024

Editorial review

Reviewed by the Biohack Blueprint research team

Last verified

Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction