Health Benefits of Glycine

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Glycine is a versatile amino acid with numerous health benefits. Its roles in enhancing immune function, improving metabolic health, protecting muscle tissue, mitigating aging effects, and preventing disease highlight its potential as a valuable dietary supplement. Further research is warranted to fully elucidate the mechanisms underlying these benefits and to explore its applications in clinical settings.

Glycine, a non-essential amino acid, has been extensively studied for its diverse health benefits. This article explores the various ways in which glycine contributes to health, focusing on its roles in immunity, metabolism, muscle function, and disease prevention.

Glycine and Immune Function

Glycine has been shown to play a significant role in regulating mucosal immunity and the intestinal microbial composition. A study on weaned piglets demonstrated that dietary supplementation with 2% glycine improved the intestinal immunological barrier function and altered the microbial composition favorably. This led to enhanced growth performance and a reduction in pathogenic bacteria1. Additionally, glycine treatment in patients with Type 2 diabetes resulted in decreased levels of proinflammatory cytokines and increased levels of interferon-γ, suggesting a beneficial effect on both innate and adaptive immune responses2.

Glycine and Metabolic Health

Glycine supplementation has been found to have a positive impact on metabolic health. In a study involving patients with Type 2 diabetes, glycine treatment significantly lowered glycated hemoglobin (A1C) levels and reduced proinflammatory cytokines, which are often elevated in metabolic disorders2. Furthermore, glycine has been shown to alleviate lipopolysaccharide (LPS)-induced intestinal injury in piglets by maintaining mTOR signaling and suppressing AMPK, TLR4, and NOD signaling pathways, thereby improving energy status and protein synthesis3.

Glycine and Muscle Function

Glycine has protective effects on muscle tissue, particularly in conditions of stress such as ischemia-reperfusion injury. In a canine model, glycine preserved muscle function, decreased edema, and reduced muscle necrosis following ischemia-reperfusion injury4. Additionally, glycine supplementation in piglets challenged with LPS enhanced muscle protein mass by maintaining Akt-mTOR-FOXO1 signaling and suppressing TLR4 and NOD2 signaling, which are involved in inflammatory responses5.

Glycine and Aging

Glycine, when combined with N-acetylcysteine (GlyNAC), has been shown to improve several age-related defects in older adults. A randomized clinical trial demonstrated that GlyNAC supplementation improved glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, and physical function, thereby addressing multiple hallmarks of aging6.

Glycine and Disease Prevention

Glycine has potential chemopreventive properties. In a study on rats, dietary glycine significantly inhibited the development of liver tumors caused by the peroxisome proliferator WY-14,643. Glycine prevented the formation of small, medium, and large tumors, indicating its effectiveness in reducing cancer risk8. Additionally, glycine supplementation in diabetic rats inhibited aldose reductase activity, which is implicated in the development of diabetic cataracts, thereby offering protective effects against this complication7.