Glutamine is the most abundant amino acid in the body, most of it is stored in the muscles, but is also found in the brain, lungs, liver and blood. It is a nonessential amino acid because it can be produced by another amino acid, glutamic acid, and may be considered conditionally essential because in times of stress (such as an intense workout) the body alone can not cope with its synthesis.
The cells of the small intestine, kidney cells and cells of the immune system are major consumers of glutamine , they use it as an energy substrate.
Glutamine supplements are recommended for sport because it was found that this substance prevents muscle catabolism, boosts protein synthesis, increases the reserves of glycogen, helps recovery after a heavy exercise and stimulates the immune system. Under conditions of metabolic stress it is noted a decrease in plasma glutamine levels. During intense exercise the muscles release glutamine in the blood, which causes a depletion of about 35 % of the reserves of glutamine. In this situation the skeletal muscles undergo a degradation (an explanation secondary to this process is the necessity of providing glutamine to the cells of the body).
A study conducted by the National Institute of Sports Medicine of Bucharest and presented to the National Conference of Sports Medicine (October 2005) followed the evolution of biochemical and functional parameters after 12 weeks of intense training and daily supplementation of glutamine. In this study participated 20 athletes who have been practicing aerobics and with an average age of 20 years. They were divided into 2 groups. To those of the first group were given fruit juices with Glutamine, 1 gram per every kg per body weight per day, while the second group received only simple juices. Both groups followed the same type of workout and diet. There were followed several parameters: Creatine Kinase (CK), lactate dehydrogenase (LDH or LD), Tone Muscle, Electromyography (EMG) , growth hormone (GH), cortisol, and thyrotropin (TSH).
In the case of the athletes that received glutamine it was noticed an important reduction in the enzymatic level of CK and of the LDH after exercising and a higher yield of muscle activity. There has been noticed a better muscle tone in repose mode. In the other group there were no such changes. The group that received glutamine showed the following improvements in functional neuromuscular factors: increased contraction strength and motor speed. It was also observed increased levels of growth hormone (GH).
The conclusion of the researchers from INMS was that the “Glutamine supplementation is beneficial to make a significant contribution to achieve a high level of training and metabolic recovery after intense exercise.” The use of glutamine manifests these effects not only in the case of athletes of aerobics but for all cases of the training of athletes who workout for increased strength.
It is absolutely necessary that the L-glutamine both in free form to be bio available.