Tier 4 — mechanistic

De Novo Glycine Synthesis Is Reduced in Adults With Morbid Obesity and Increases Following Bariatric Surgery

Tan HC, Hsu JW, Tai ES, Chacko S, Wu V, Lee CF, Kovalik JP, Jahoor F
Frontiers in endocrinology 2022 13:900343

Bibliography

PubMed
PMID 35757406
PubMed Central
PMC9219591
DOI
10.3389/fendo.2022.900343
Trial registry
View on ClinicalTrials.gov Registered trial — results not yet published in a peer-reviewed journal.
Funding
National Medical Research Council Transition Award, NMRC/TA/0063/2018.
Competing interests
The authors declared no relevant commercial or financial relationships.

Study snapshot

DesignHuman observational study
ModelAdult humans
Sample21 adults with morbid obesity and 21 healthy-weight controls; 17 reassessed after surgery
InterventionStable-isotope measurements before and 6 months after bariatric surgery; no therapeutic glycine intervention
DurationCross-sectional comparison and 6-month follow-up
EndpointsDe novo glycine synthesis; Plasma glycine; Insulin resistance

What the study showed, in plain terms

Tracer measurements suggest that obesity-associated low glycine can reflect reduced synthesis. Glycine synthesis and concentration increased after bariatric surgery alongside metabolic improvement.

Key findings

  • Adults with obesity had lower glycine synthesis and circulating glycine than controls.
  • Seventeen participants were reassessed after surgery.

What this study can and cannot tell us

Surgery changes weight, diet and many metabolic processes simultaneously.

The findings do not prove that giving glycine reproduces the effects of weight loss.

Related papers in the corpus

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Gannon MC et al. · The American journal of clinical nutrition · 2002
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Effect of glycine on insulin secretion and action in healthy first-degree relatives of type 2 diabetes mellitus patients
González-Ortiz M et al. · Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme · 2001
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Glycine treatment decreases proinflammatory cytokines and increases interferon-gamma in patients with type 2 diabetes
Cruz M et al. · Journal of endocrinological investigation · 2008
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Oral supplementation with glycine reduces oxidative stress in patients with metabolic syndrome, improving their systolic blood pressure
Díaz-Flores M et al. · Canadian journal of physiology and pharmacology · 2013
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Metabolic impact of dietary glycine supplementation in individuals with severe obesity
Tan HC et al. · Scientific reports · 2025
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Low serum glycine strengthens the association between branched-chain amino acids and impaired insulin sensitivity assessed before and after weight loss in a population with pre-diabetes: The PREVIEW_NZ cohort
Lim JJ et al. · Clinical nutrition (Edinburgh, Scotland) · 2024

Editorial review

Reviewed by the Biohack Blueprint research team

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