Plasma glycine decelerates biological aging via the redox-inflammatory axis: A large-scale study modulated by sex and dietary patterns

Huan Xu and colleagues analyzed UK Biobank data to examine plasma glycine and biological aging measured with Klemera-Doubal Method residuals. Higher glycine was associated with lower biological-age residuals. The reported coefficient was -0.729 (95% CI -0.815 to -0.643). Mediation analyses attributed 3.9% to 25.6% of the association to inflammatory and oxidative-stress markers. Dietary context modified the association in men. Among men consuming a pro-inflammatory and pro-oxidative diet, the coefficient was -0.757 (95% CI -1.294 to -0.220). With an anti-inflammatory and anti-oxidative diet, it was -0.939 (95% CI -1.402 to -0.476). The interaction p value was 0.014. No comparable interaction appeared in women. This is an exposure analysis, not a glycine supplementation trial. It cannot show that taking glycine slows aging or improves survival. The result is still relevant because it connects an available amino acid to an established biological-age metric and proposes a redox-inflammatory pathway. The diet interaction argues against treating glycine as a context-free longevity molecule. The paper supports hypothesis generation and trial design, not a supplement recommendation.

Plasma glycine negatively correlated with biological aging, partly through modulation of the redox-inflammatory axis. The male-specific vulnerability to pro-oxidative and pro-inflammatory diets highlights that glycine's efficacy is contingent upon a favorable nutritional context. These results support for precision interventions integrating glycine optimization with anti-inflammatory dietary patterns to extend healthy longevity.