Glutamine

Glutamine is a non-essential amino acid that plays a crucial role in various bodily functions, including protein synthesis, immune system function, and digestive health[1][4]. It is the most abundant naturally occurring amino acid in the human body and can directly cross the blood-brain barrier, making it one of the few amino acids with this ability[1].

Nutrition and Conditionally Essential Status

Glutamine is obtained through the catabolism of proteins in foods and is usually synthesized by the body in sufficient amounts[1]. However, in certain situations such as growth, wound healing, or severe illness, the body's demand for glutamine increases, and it becomes conditionally essential, meaning it must be obtained from the diet[1].

Sickle Cell Disease

The U.S. Food and Drug Administration (FDA) has approved L-glutamine oral powder, marketed as Endari, to reduce severe complications of sickle cell disease in people aged five years and older with the disorder[1]. Clinical trials have shown that L-glutamine oral powder can reduce hospital visits, hospitalizations, and days in the hospital for sickle cell crises, as well as the occurrence of acute chest syndrome, a life-threatening complication of sickle cell disease[1].

Forms and Administration

Glutamine can be administered in its free form or bonded with another amino acid, known as the dipeptide form[2]. Dipeptides such as l-alanyl-l-glutamine (Ala-Gln) have been shown to reduce infectious complications, length of hospital stay, and mortality in critically ill patients when given parenterally[2].

Immune Function and Metabolism

Glutamine is a key player in immune cell function, particularly during infection and high catabolism[2]. It is converted into glutamate, aspartate, and alanine by undergoing partial oxidation to CO2, and can be used as a precursor for the synthesis of other amino acids[2].

Supplements and Side Effects

Glutamine supplements are available, but their benefits for healthy individuals are unclear[3][4][5]. The only FDA-approved use of glutamine is to reduce serious complications of sickle cell disease[3][4]. Some research suggests that taking glutamine may provide benefits in treating certain conditions, but more research is needed to understand its potential benefits[4][5]. Common side effects of L-glutamine oral powder include constipation, nausea, headache, abdominal pain, cough, pain in the extremities, back pain, and chest pain[1].

In summary, glutamine is an amino acid that plays a vital role in various bodily functions, including protein synthesis, immune system function, and digestive health. While it is usually synthesized by the body in sufficient amounts, it can become conditionally essential in certain situations. Its use as a supplement is approved for reducing complications of sickle cell disease, but its benefits for healthy individuals are unclear and require further research.

Citations:

[1] https://en.wikipedia.org/wiki/Glutamine

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6266414/

[3] https://www.mayoclinic.org/drugs-supplements/glutamine-oral-route/description/drg-20064099

[4] https://my.clevelandclinic.org/health/articles/glutamine

[5] https://www.healthline.com/nutrition/glutamine