Compendium of the most significant studies with reference to properties, intake, effects.

Holecek M. Side effects of long-term glutamine supplementation. JPEN J Parenter Enteral Nutr. 2013 Sep;37(5):607-16. doi: 10.1177/0148607112460682.

Abstract. Some people consume chronically glutamine (GLN) in high quantities (~40 g/d), although a number of biochemical pathways and cellular functions may be negatively affected. The following side effects of GLN supplementation are discussed...

Gleeson M. Dosing and efficacy of glutamine supplementation in human exercise and sport training. J Nutr. 2008 Oct;138(10):2045S-2049S. doi: 10.1093/jn/138.10.2045S.

Abstract. Some athletes can have high intakes of l-glutamine because of their high energy and protein intakes and also because they consume protein supplements, protein hydrolysates, and free amino acids. Prolonged exercise and periods of heavy training are associated with a decrease in the plasma glutamine concentration and this has been suggested to be a potential cause of the exercise-induced immune impairment and increased susceptibility to infection in athletes.

Reeds PJ, Burrin DG. Glutamine and the bowel. J Nutr. 2001 Sep;131(9 Suppl):2505S-8S; discussion 2523S-4S. doi: 10.1093/jn/131.9.2505S. 

Abstract. Since the pioneering work of Windmueller and Spaeth, the importance of glutamine to the support of intestinal mucosal metabolic function has become generally accepted. Nevertheless, the mechanisms underlying this role still remain obscure. This paper explores a number of questions...

Kim H. Glutamine as an immunonutrient. Yonsei Med J. 2011 Nov;52(6):892-7. doi: 10.3349/ymj.2011.52.6.892.

Abstract. Dietary supplementation with nutrients enhancing immune function is beneficial in patients with surgical and critical illness. Malnutrition and immune dysfunction are common features in hospitalized patients. Specific nutrients with immunological and pharmacological effects, when consumed in amounts above the daily requirement, are referred to as immune-enhancing nutrients or immunonutrients. Supplementation of immunonutrients is important especially for patients with immunodeficiency, virus or overwhelming infections accompanied by a state of malnutrition. Representative immunonutrients are arginine, omega-3 fatty acids, glutamine, nucleotides, beta-carotene, and/or branched-chain amino acids.

Cruzat V, Macedo Rogero M, Noel Keane K, Curi R, Newsholme P. Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation. Nutrients. 2018 Oct 23;10(11):1564. doi: 10.3390/nu10111564.

Abstract. Glutamine release to the circulation and availability is mainly controlled by key metabolic organs, such as the gut, liver, and skeletal muscles. During catabolic/hypercatabolic situations glutamine can become essential for metabolic function, but its availability may be compromised due to the impairment of homeostasis in the inter-tissue metabolism of amino acids.

Wischmeyer PE. The glutamine debate in surgery and critical care. Curr Opin Crit Care. 2019 Aug;25(4):322-328. doi: 10.1097/MCC.0000000000000633.

Abstract. Purpose of review: Glutamine (GLN) is a versatile amino acid, long believed to have important implications in ICU and surgical patients. An extensive body of data examining GLN supplementation of TPN demonstrated a consistent signal of improved outcomes. However, recently signals of risk have come from two large-scale multicenter trials evaluating GLN (and other nutrients) at high dose and as primary pharmaconutrients, not as supplementation to complete nutrition. These trials indicate a risk of increased mortality when GLN is given to patients in shock, renal failure, and early in acute phase of critical care.

Kawakami I, Yoshino H, Fukumoto W, Tamai M, Okamura S, Osako Y, Sakaguchi T, Inoguchi S, Matsushita R, Yamada Y, Tatarano S, Nakagawa M, Enokida H. Targeting of the glutamine transporter SLC1A5 induces cellular senescence in clear cell renal cell carcinoma. Biochem Biophys Res Commun. 2022 Apr 20;611:99-106. doi: 10.1016/j.bbrc.2022.04.068.

Abstract. In recent years, cancer metabolism has attracted attention as a therapeutic target, and glutamine metabolism is considered one of the most important metabolic processes in cancer. Solute carrier family 1 member 5 (SLC1A5) is a sodium channel that functions as a glutamine transporter....