Glycine treatment decreases proinflammatory cytokines and increases interferon-gamma in patients with type 2 diabetes

J Endocrinol Invest. 2008 Aug;31(8):694-9. doi: 10.1007/BF03346417.


Background: Amino acids have been shown to stimulate insulin secretion and decrease glycated hemoglobin (A1C) in patients with Type 2 diabetes. In vitro, glycine reduces tumor necrosis factor (TNF)-alpha secretion and increases interleukin-10 secretion in human monocytes stimulated with lipopolysaccharide. The aim of this study was to determine whether glycine modifies the proinflammatory profiles of patients with Type 2 diabetes.

Materials/subjects and methods: Seventy-four patients, with Type 2 diabetes were enrolled in the study. The mean age was 58.5 yr, average age of diagnosis was 5 yr, the mean body mass index was 28.5 kg/m2, the mean fasting glucose level was 175.5 mg/dl and the mean A1C level was 8%. They were allocated to one of two treatments, 5 g/d glycine or 5 g/d placebo, po tid, for 3 months.

Results: A1C levels of patients given glycine were significantly lower after 3 months of treatment than those of the placebo group. A significant reduction in TNF-receptor I levels was observed in patients given glycine compared with placebo. There was a decrease of 38% in the interferon (IFN)-gamma level of the group treated with placebo, whereas that of the group treated with glycine increased up to 43%. These data showed that patients treated with glycine had a significant decrease in A1C and in proinflammatory cytokines and also an important increase of IFN-gamma.

Conclusion: Treatment with glycine is likely to have a beneficial effect on innate and adaptive immune responses and may help prevent tissue damage caused by chronic inflammation in patients with Type 2 diabetes.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cytokines / blood*
  • Cytokines / metabolism
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diabetes Mellitus, Type 2 / metabolism
  • Female
  • Glycine / administration & dosage
  • Glycine / pharmacology
  • Glycine / therapeutic use*
  • Humans
  • Hypoglycemic Agents / administration & dosage
  • Inflammation Mediators / blood
  • Inflammation Mediators / metabolism
  • Interferon-gamma / blood*
  • Interferon-gamma / metabolism
  • Interleukin-6 / blood
  • Male
  • Middle Aged
  • Placebos
  • Resistin / blood


  • Cytokines
  • Hypoglycemic Agents
  • IL6 protein, human
  • Inflammation Mediators
  • Interleukin-6
  • Placebos
  • Resistin
  • Interferon-gamma
  • Glycine