What is glutamine?

Cancers treated or prevented: All cancers currently treated with chemotherapy or radiation

Delivery routes: Glutamine can be taken orally by capsules, powder, or tablets. In the clinical setting, glutamine can be part of an enteral liquid formula given by feeding tube through the nose, stomach, or small intestine. Glutamine can also be given intravenously.

How this compound works: Although glutamine is found largely as a component of proteins (skeletal muscle in particular), it serves a variety of functions in the body. Stress conditions such as injury, burns, critical illness, or high-intensity exercise cause a greatly increased need for glutamine. Glutamine is considered a conditionally essential amino acid under these stress conditions, since dietary supplementation of glutamine is necessary. The gastrointestinal tract is the largest user of glutamine, particularly as a source of energy. Glutamine is important in wound healing and helps to mobilize components of the immune system. It also helps to maintain the integrity of the intestinal lining to prevent entry of bacteria and fungi.

Cancer cells have a great demand for glutamine as an energy source; this can deplete glutamine stores in muscle and other body tissues. Laboratory studies indicate that glutamine is necessary for the functioning of T lymphocytes and natural killer cells, which are components of the immune system. The depletion of body glutamine, therefore, could compromise the role of the immune system in the protection against cancer. Some researchers were concerned about supplementing cancer patients with glutamine, thinking that supplementation could increase tumor growth. Such supplementation has been found, however, to increase glutamine stores in the body and to improve intestinal and immune function.

In addition, studies have indicated that glutamine may alleviate the side effects of chemotherapy and radiation therapy. Glutamine supplementation has resulted in decreased intestinal mucosa ulceration and mouth inflammation. Peripheral neuropathy (numbness in extremities, motor weakness) often limits chemotherapeutic dosages. Glutamine may reduce the severity of neurological disorders, thereby permitting more effective dosages. Researchers believe that glutamine may work by restoring cellular levels of glutathione, a molecule that contains a sulfur group which binds to drugs and carcinogens. Glutamine supplementation increases the glutathione level in the body, thereby helping to reduce toxic drug levels. Glutamine supplementation has been shown to increase the accumulation of the chemotherapeutic drug methotrexate inside tumor cells, thereby increasing its killing effect.

Side effects: Since glutamine is so abundant in the body, even doses of up to 21 grams daily are well tolerated. Side effects are mainly gastrointestinal and include constipation and bloating.

Bibliography

Farkas, Etelka, and Maxim Ryadnov. Amino Acids, Peptides and Proteins. Cambridge: Royal Society of Chemistry, 2014. Digital file.

Gaurav, Kumar, et al. "Glutamine: A Novel Approach to Chemotherapy Induced Toxicity." Indian Journal of Medical and Paediatric Oncology 33.1 (2012): 13–20. Print.

Hensley, Christopher T., Ajla T. Wasti, and Ralph J. DeBerardinis. "Glutamine and Cancer: Cell Biology, Physiology, and Clinical Opportunities." Journal of Clinical Investigation 123.9 (2013): 3678–84. Print.

Topkan, Erkan, et al. "Influence of Oral Glutamine Supplementation on Survival Outcomes of Patients Treated with Concurrent Chemoradiotherapy for Locally Advanced Non-Small Cell Lung Cancer." BMC Cancer 12.1 (2012): 502–11. Print.

Yang, Lifeng, et al. "Metabolic Shifts toward Glutamine Regulate Tumor Growth, Invasion and Bioenergetics in Ovarian Cancer." Molecular Systems Biology 10.5 (2014). Print.