Research

Hormonal

Adherence to a vegan diet increases circulating glycine levels despite lower dietary intake, mediated by the reduction of the gut pathobiont Bilophila wadsworthia and its glycine reductase pathway activity.

If you switch to a vegan diet, your body may naturally increase its levels of glycine, an amino acid linked to better insulin sensitivity and metabolic health. This happens not because you eat more glycine, but because your gut bacteria change to stop consuming it. You don't need to supplement glycine; simply adhering to a whole-food vegan diet appears to trigger this beneficial metabolic shift.

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Despite lower dietary glycine intake, vegan diet subjects exhibited elevated serum glycine levels linked to reduced abundance of the gut pathobiont Bilophila wadsworthia. Functional studies demonstrated that B. wadsworthia metabolizes glycine via the glycine reductase pathway and modulates host glycine availability.
Matthew M. Carter et al. · medRxiv · 2025

Why this rating

Strong human twin study data supported by in vitro and gnotobiotic mouse mechanistic validation.

Source

A gut pathobiont regulates circulating glycine and host metabolism in a twin study comparing vegan and omnivorous diets

Matthew M. Carter et al. · medRxiv · 2025

DOI 10.1101/2025.01.08.25320192

preprint · n=42Cited 2×
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DOI resolved against Crossref · corpus check 2026-06-10

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