L-glutamine

Glutamine/Nutrient depletion:

  • Amino acidsAmino acids: In human research, glutamine supplementation altered levels of other amino acids, including a decrease in glycine, proline, and arginine (179) or an increase in glycine, arginine, alanine, or ornithine (180; 51; 181). In human and animal research, glutamine supplementation increased plasma taurine (182). In human research, nonessential amino acids did not appear to increase following glutamine supplementation (183). Other studies showed no effect on amino acids in general (184). Fish determined that glutamine-enriched tube feeding and TPN can result in similar profiles for most plasma amino acids at carefully matched doses (185).
  • AnestheticsAnesthetics: General anesthesia resulted in a decrease in muscle glutamine in human research (125).
  • CarbohydrateCarbohydrate: During exercise, a low carbohydrate diet resulted in decreased plasma glutamine in untrained men (176).
  • GlucoseGlucose: Glutamine increased insulin-mediated glucose disposal in trauma patients (68) and altered glucose homeostasis during and after exercise (187). In animal research, glutamine induced insulin resistance in adipose tissue, improving insulin signaling in liver and muscle (188). Also, increased glutamine availability blunted the effect of insulin action on glucose production and enhanced insulin-mediated glucose utilization (189).
  • GlutamineGlutamine: In human research, glutamine supplementation resulted in increases in glutamine in some (2; 95; 5; 71; 179; 3; 72; 105; 36; 190; 51; 181; 107) but not all (19; 59; 39; 191) studies. In human research, gut mucosal and muscle glutamine also increased with supplementation (192; 193). In animal research, glutamine increased muscle and plasma glutamine, but not tumor levels of glutamine (129).
  • Low-carbohydrate dietLow-carbohydrate diet: During exercise, a low-carbohydrate diet resulted in decreased plasma glutamine in untrained men (176).