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What is glutamine? What is its role and what are its benefits? For health as well as for sports performance, glutamine is a real ally. Nutrimuscle explains everything there is to know on the subject.
What is glutamine?
An amino acid belonging to the family of "conditionally essential" amino acids , glutamine is found in abundance in the body.
Daily diet provides 5 to 10 g, on average. It is found in meat, fish, eggs, seafood, legumes (lentils, chickpeas, flageolet beans, etc.), spinach, oilseeds (walnuts, almonds, hazelnuts) and dairy products.
The role of glutamine
It is the most abundant amino acid in the blood and muscles. It plays many roles in our body, including the immune system, protein synthesis, maintaining the integrity of the intestinal wall and acid-base balance. It contributes to joint and tendon health by helping to produce glucosamine, a component of cartilage.
Glutamine deficiency
Although our body is quite capable of producing it, certain factors can cause glutamine deficiencies. These factors include physiological stress (accident, burn, surgery, serious illness), but also high-intensity physical activity.
Indeed, in bodybuilders or athletes who train regularly, this amino acid is essential: the body's ability to synthesize it is much lower than the destruction caused by the effort. The drop in performance is linked to the decrease in plasma glutamine levels.
Effects on athletes
Reduce intestinal permeability: Chronic supplementation of this amino acid reduces exercise-induced intestinal permeability, and acute supplementation prevents the increase in this permeability during exercise (4).
Fight against catabolism: This amino acid helps fight against catabolism and accelerates muscle anabolism.
Alleviate muscle soreness: Chronic oral administration of can alleviate muscle tissue damage and inflammation induced by intense physical exertion (5).
Improve performance: According to one study, it appears that acute glutamine supplementation combined with maltodextrin, 2 hours before exercise, is more effective in preventing the decline in anaerobic power than the consumption of pure carbohydrate or glutamine in repeated episodes of the RAST protocol. Thus, carbohydrate and peptide glutamine supplementation improved the physical performance of athletes during repeated competitions (6).
Accelerate recovery: After exercise, reduced glutamine availability can be considered an overtraining syndrome. Increased availability may contribute to decreased inflammation and health benefits associated with optimal training. Thus, supplementation may improve immunocompetence after intense exercise (7).
A study of glutamine supplementation during a simulated wildfire showed that men and women who ingested it had a slower recovery time than participants who ingested a placebo. Indeed, their fatigue, cellular stress and perceived effort were less important. Supplementation therefore improves recovery after exercise (8).
Health benefits
In the elderly
Combating age-related diseases: According to a recent study, L-glutamine administration could represent an important therapeutic strategy to reduce muscle loss (sarcopenia) in catabolic and aging diseases (9).
Fight depression: Glutamine is thought to have antidepressant effects through increased blood glutamate levels and glutamatergic activity in the medial prefrontal cortex (10).
Strengthening immune defenses: It plays a role in the immune system, essential for the proliferation of lymphocytes (11).
In people with intolerances
Food intolerance: Glutamine may improve intestinal mucosal blood flow and reduce intestinal damage especially after burn injury, thereby reducing the permeability of the intestinal mucosa. (12).
In people with diabetes: Supplementation may reduce blood sugar levels in patients with type 1 diabetes (T1D), who do not have residual insulin secretion. (13).
Alcohol-related damage: This amino acid also improves intestinal and liver damage induced by alcohol in particular. (14).
In people with sickle cell disease: A study in patients with sickle cell disease showed that in children and adults with sickle cell anemia, the median number of painful crises over 48 weeks was lower in patients taking oral l-glutamine. (15).
In people wanting to lose weight
According to one study, glutamine administration reduced waist circumference and serum lipopolysaccharide levels in overweight volunteers . In the obese group, supplementation helped decrease waist circumference and serum insulin levels. In rats fed a high-fat diet, it reduced adiposity and improved insulin action. (16).
When and how to take glutamine?
Glutamine can be taken at different times, depending on the desired effects.
- Between meals or every 3 hours to fill anabolic gaps. (2 to 3 g)
- During training to regulate ammonia production linked to taking BCAA
- After training to speed up recovery (2 to 3 g).
- In the evening to limit proteolysis (6 capsules)
- At night to ensure a positive nitrogen balance (6 capsules + 8 BCAA capsules).
It is recommended to accompany it with a tempered carbohydrate drink.
Synergy
It is commonly believed that a high-protein diet provides sufficient levels of glutamine to meet sports needs. However, the opposite is true: the more protein you consume, the greater your glutamine needs. In fact, glutamine helps neutralize the acid released by amino acids. It is therefore recommended to supplement with glutamine when you exercise regularly.
Scientific references
(1) Phillips GC. Glutamine: the nonessential amino acid for performance enhancement. Curr Sports Med Rep. 2007 Jul;6(4):265-8.
(2) Yan B. Metabolomic investigation into variation of endogenous metabolites in professional athletes subject to strength-endurance training. J Appl Physiol. 2009 Feb;106(2):531-8.
(3) Gleeson M. Dosing and efficacy of glutamine supplementation in human exercise and sport training. J Nutr. 2008 Oct;138(10):2045S-2049S.
(4) Zuhl, M., Dokladny, K., Mermier, C., Schneider, S., Salgado, R., & Moseley, P. (2014). The effects of acute oral glutamine supplementation on exercise-induced gastrointestinal permeability and heat shock protein expression in peripheral blood mononuclear cells. Cell Stress And Chaperones, 20(1), 85-93. doi:10.1007/s12192-014-0528-1
(5) Raizel, R., & Tirapegui, J. (2018). Role of glutamine, as free or dipeptide form, on muscle recovery from resistance training: a review study. Nutrire, 43(1). doi:10.1186/s41110-018-0087-9
(6) Khorshidi-Hosseini, M., & Nakhostin-Roohi, B. (2013). Effect of Glutamine and Maltodextrin Acute Supplementation on Anaerobic Power. Asian Journal Of Sports Medicine, 4(2). doi:10.5812/asjsm.34495
(7) Agostini, F., & Biolo, G. (2010). Effect of physical activity on glutamine metabolism. Current Opinion In Clinical Nutrition And Metabolic Care, 13(1), 58-64. doi:10.1097/mco.0b013e328332f946
(8) Nava, R., Zuhl, M., Moriarty, T., Amorim, F., Bourbeau, K., & Welch, A. et al. (2019). The Effect of Acute Glutamine Supplementation on Markers of Inflammation and Fatigue During Consecutive Days of Simulated Wildland Firefighting. Journal Of Occupational And Environmental Medicine, 61(2), e33-e42. doi: 10.1097/jom.0000000000001507
(9) Girven, M., Dugdale, H., Owens, D., Hughes, D., Stewart, C., & Sharples, A. (2016). l-glutamine Improves Skeletal Muscle Cell Differentiation and Prevents Myotube Atrophy After Cytokine (TNF-α) Stress Via Reduced p38 MAPK Signal Transduction. Journal Of Cellular Physiology, 231(12), 2720-2732. doi:10.1002/jcp.25380
(10) Son, H., Baek, J., Go, B., Jung, D., Sontakke, S., & Chung, H. et al. (2018). Glutamine has antidepressive effects through increments of glutamate and glutamine levels and glutamatergic activity in the medial prefrontal cortex. Neuropharmacology, 143, 143-152. doi: 10.1016/j.neuropharm.2018.09.040
(11) Cruzat, V., Macedo Rogero, M., Noel Keane, K., Curi, R., & Newsholme, P. (2018). Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation. Nutrients, 10(11), 1564. doi: 10.3390/nu10111564
(12) Wang, Z. (2018). Effects of glutamine on intestinal mucus barrier after burn injury. American Journal Of Translational Research, 10(11), 3833-3846.
(13) Darmaun, D., Torres-Santiago, L., & Mauras, N. (2019). Glutamine and type 1 diabetes mellitus. Current Opinion In Clinical Nutrition And Metabolic Care, 1. doi: 10.1097/mco.0000000000000530
(14) Chaudhry, K., Shukla, P., Mir, H., Manda, B., Gangwar, R., & Yadav, N. et al. (2016). Glutamine supplementation attenuates ethanol-induced disruption of apical junctional complexes in colonic epithelium and ameliorates gut barrier dysfunction and fatty liver in mice. The Journal Of Nutritional Biochemistry, 27, 16-26. doi: 10.1016/j.jnutbio.2015.08.012
(15) Niihara, Y., Miller, S., Kanter, J., Lanzkron, S., Smith, W., & Hsu, L. et al. (2018). A Phase 3 Trial of l-Glutamine in Sickle Cell Disease. New England Journal Of Medicine, 379(3), 226-235. doi:10.1056/nejmoa1715971.
(16) Abboud, K., Reis, S., Martelli, M., Zordão, O., Tannihão, F., & de Souza, A. et al. (2019). Oral Glutamine Supplementation Reduces Obesity, Pro-Inflammatory Markers, and Improves Insulin Sensitivity in DIO Wistar Rats and Reduces Waist Circumference in Overweight and Obese Humans. Nutrients, 11(3), 536. doi: 10.3390/nu11030536
