Glutamine (symbol Gln or Q) is an α-amino acid that is used in the biosynthesis of proteins. Its side chain is similar to that of glutamic acid, except the carboxylic acid group is replaced by an amide. It is classified as a charge-neutral, polar amino acid. It is non-essential and conditionally essential in humans, meaning the body can usually synthesize sufficient amounts of it, but in some instances of stress, the body’s demand for glutamine increases, and glutamine must be obtained from the diet. It is encoded by the codons CAA and CAG.
In human blood, glutamine is the most abundant free amino acid.
The dietary sources of glutamine includes especially the protein-rich foods like beef, chicken, fish, dairy products, eggs, vegetables like beans, beets, cabbage, spinach, carrots, parsley, vegetable juices and also in wheat, papaya, Brussels sprouts, celery, kale and fermented foods like miso.
Glutamine plays a role in a variety of biochemical functions:
Protein synthesis, as any other of the 20 proteinogenic amino acids
Lipid synthesis, especially by cancer cells.
Regulation of acid-base balance in the kidney by producing ammonium
Cellular energy, as a source, next to glucose
Nitrogen donation for many anabolic processes, including the synthesis of purines
Carbon donation, as a source, refilling the citric acid cycle
Nontoxic transporter of ammonia in the blood circulation
Precursor to the neurotransmitter glutamate
Glutamine is marketed as medical food and is prescribed when a medical professional believes a person in their care needs supplementary glutamine due to metabolic demands beyond what can be met by endogenous synthesis or diet.
Ceasing glutamine supplementation in people adapted to very high consumption may initiate a withdrawal effect, raising the risk of health problems such as infections or impaired integrity of the intestine.
Studies support the positive effects of the chronic oral administration of the supplement on the injury and inflammation induced by intense aerobic and exhaustive exercise.
Burns. Administering glutamine through a feeding tube or intravenously (by IV) seems to reduce infections, shorten hospital stays, and improve wound healing in people with burns.
Critical illness (trauma). There is some evidence that glutamine keeps bacteria from moving out of the intestine and infecting other parts of the body after major injuries. However, not all evidence is consistent. It is not clear if glutamine reduces the risk of death in critically ill people. Some studies suggest that it might reduce the risk of death, while others do not.
Treating weight loss and intestinal problems in people with HIV/AIDs disease. Taking glutamine by mouth seems to help HIV/AIDS patients absorb food better and gain weight. Doses of 40 grams per day seem to produce the best effect.
Soreness and swelling inside the mouth, caused by chemotherapy treatments. Some evidence suggests that glutamine reduces soreness and swelling inside the mouth caused by chemotherapy. However, glutamine does not seem to have this effect for all chemotherapy patients. It is not clear which patients are likely to benefit. Some researchers suspect that chemotherapy patients who do not have enough glutamine to start with are most likely to be helped. Surgery. Giving glutamine intravenously (by IV) along with intravenous nutrition seems to improve immune function and reduce complications related to infections after major surgery. Also, giving glutamine intravenously (by IV) along with intravenous nutrition after a bone marrow transplant seems to reduce the risk of infection and improve recovery compared to intravenous nutrition alone. However, not all people who undergo major surgery or who receive bone marrow transplants seem to benefit from glutamine.