Review: Do Horses Receive Optimum Amounts of Glutamine in Their Diets?

Authors

  • Michael I. Lindinger The Nutraceutical Alliance, Torrevieja, Alicante, 03185, Spain

DOI:

https://doi.org/10.30564/vsr.v2i1.1619

Abstract

In some species of growing mammals glutamine is an essential amino acid that, if inadequate in the diet, is needed for normal growth and development. It is thus sometimes considered to be a conditionally essential amino acid in some species. A review of studies that have measured L-glutamine concentrations ([glutamine]) in horses demonstrates that plasma [glutamine] has routinely been reported to be much lower (~330 µmol/L) than in other mammals (> 600 µmol/L). Plasma [glutamine] represents the balance between intestinal transport into the blood after hepatic first pass, tissue synthesis and cellular extraction. The hypothesis is proposed that sustained low plasma [glutamine] represents a chronic state of sub-optimal glutamine intake and glutamine synthesis that does not meet the requirements for optimum health. While this may be without serious consequence in feral and sedentary horses, there is evidence that provision of supplemental dietary glutamine ameliorates a number of health consequences, particularly in horses with elevated metabolic demands. The present review provides evidence that glutamine is very important (and perhaps essential) for intestinal epithelial cells in mammals including horses, that horses with low plasma [glutamine] represents a sub-optimal state of well-being, and that horses supplemented with glutamine exhibit physiological and health benefits.

Keywords:

Conditionally essential amino acid; Intestinal health; Immune health; Hypoglutaminemia; Skeletal muscle; Glutamine metabolism

References

[1] Smith RJ. Glutamine metabolism and its physiologic importance. JPEN J Parenter Enteral Nutr, 1990. 14(4 Suppl): 40S-44S. doi: 10.1177/014860719001400402

[2] Watford M. Glutamine and glutamate: Nonessential or essential amino acids? Animal Nutrition, 2015. 1(3): 119–122. doi: 10.1016/j.aninu.2015.08.008.

[3] Morris CR, Hamilton-Reeves J, Martindale RG, Sarav M, Ochoa Gautier JB. Acquired amino acid deficiencies: a focus on arginine and glutamine. Nutr Clin Pract, 2017. 32(1_suppl):30S-47S. doi: 10.1177/0884533617691250.

[4] Coqueiro AY, Rogero MM, Tirapegui J. Glutamine as an anti-fatigue amino acid in sports nutrition. Nutrients, 2019. 11(4). pii: E863. doi: 10.3390/nu11040863.

[5] Darmaun D, Torres-Santiago L, Mauras N. Glutamine and type 1 diabetes mellitus: is there a role in glycemic control? Curr Opin Clin Nutr Metab Care, 2019. 22(1): 91-95. doi: 10.1097/MCO.0000000000000530.

[6] Oliveira GP, de Abreu MG, Pelosi P, Rocco PR. Exogenous glutamine in respiratory diseases: myth or reality? Nutrients, 2016. 8(2): 76. doi: 10.3390/nu8020076.

[7] Ramadan S, Lin A, Stanwell P. Glutamate and glutamine: a review of in vivo MRS in the human brain. NMR Biomed, 2013. 26(12): 1630-1646. doi: 10.1002/nbm.3045.

[8] Wang B, Wu G, Zhou Z, Dai Z, Sun Y, Ji Y, Li W, Wang W, Liu C, Han F, Wu Z. Glutamine and intestinal barrier function. Amino Acids, 2015. 47(10): 2143-2154. doi: 10.1007/s00726-014-1773-4.

[9] Meynial-Denis D. Glutamine metabolism in advanced age. Nutr Rev, 2016. 74(4): 225-236. doi: 10.1093/nutrit/nuv052.

[10] Achamrah N, Déchelotte P, Coëffier M. Glutamine and the regulation of intestinal permeability: from bench to bedside. Curr Opin Clin Nutr Metab Care, 2017. 20(1): 86-91. doi: 10.1097/MCO.0000000000000339

[11] Kim MH, Kim H. The roles of glutamine in the intestine and its implication in intestinal diseases. Int J Mol Sci, 2017. 18(5). pii: E1051. doi: 10.3390/ijms18051051.

[12] Kim H. Glutamine as an immunonutrient. Yonsei Med J, 2011. 52(6): 892-897. doi: 10.3349/ymj.2011.52.6.892.

[13] Cruzat V, Macedo Rogero M, Noel Keane K, Curi R, Newsholme P. Glutamine: metabolism and immune function, supplementation and clinical translation. Nutrients, 2018. 10(11). pii: E1564. doi: 10.3390/nu10111564.

[14] NRC. 2007. Nutrient Requirements of Horses. 6th Revised Ed. National Academy Press, Washington, DC. https://nrc88.nas.edu/nrh/

[15] Graham PM, Ott EA, Brendemuhl JH, TenBroeck SH. The effect of supplemental lysine and threonine on growth and development of yearling horses. J Anim Sci, 1994. 72: 380–386. doi: 10.2527/1994.722380x

[16] Tanner SL, Wagner AL, Digianantonio RN, Harris PA, Sylvester JT, Urschel KL. Dietary crude protein intake influences rates of whole-body protein synthesis in weanling horses. Vet J, 2014. S1090-0233(14)00258-5. doi: 10.1016/j.tvjl.2014.06.002

[17] Graham-Thiers PM, Bowen LK. Effect of protein source on nitrogen balance and plasma amino acids in exercising horses. J Anim Sci, 2011. 89(3): 729-735. doi: 10.2527/jas.2010-3081.

[18] Manso Filho HC, Costa HE, Wang Y, McKeever KH, Watford M. Distribution of L-glutamine synthetase and an inverse relationship between L-glutamine synthetase expression and intramuscular L-glutamine concentration in the horse. Comp Biochem Physiol B Biochem Mol Biol, 2008. 150(3): 326-330. doi: 10.1016/j.cbpb.2008.03.015

[19] Manso Filho HC, McKeever KH, Gordon ME, Costa HE, Lagakos WS, Watford M. Changes in L-glutamine metabolism indicate a mild catabolic state in the transition mare. J Anim Sci, 2008. 86(12): 3424-3431. doi: 10.2527/jas.2008-1054

[20] Manso Filho HC, Costa HE, Wu G, McKeever KH, Watford M. Equine placenta expresses L-glutamine synthetase. Vet Res Commun, 2009. 33(2): 175-182. doi: 10.1007/s11259-008-9167-2

[21] van den Hoven R, Bauer A, Hackl S, Zickl M, Spona J, Zentek J. Changes in intramuscular amino acid levels in submaximally exercised horses - a pilot study. J Anim Physiol Anim Nutr (Berl), 2010. 94(4): 455-464. doi: 10.1111/j.1439-0396.2009.00929.x.

[22] Rogers PA, Fahey GC Jr, Albert WW. Blood metabolite profiles of broodmares and foals. Equine Vet J, 1984. 16(3): 192-196. doi: 10.1111/j.2042-3306.1984.tb01902.x

[23] Mastellar SL, Moffet A, Harris PA, Urschel KL. Effects of threonine supplementation on whole-body protein synthesis and plasma metabolites in growing and mature horses. Vet J, 2016. 207: 147-153. doi: 10.1016/j.tvjl.2015.09.026

[24] Hackl S, van den Hoven R, Zickl M, Spona J, Zentek J. Individual differences and repeatability of post-prandial changes of plasma-free amino acids in young horses. J Vet Med A Physiol Pathol Clin Med, 2006. 53(9): 439-444. doi: 10.1111/j.1439-0442.2006.00862.x

[25] Zicker SC, Vivrette S, Rogers QR. Concentrations of amino acids in plasma from 45- to 47-week gestation mares and foetuses (Equus caballus). Comp Biochem Physiol, 1994. 108B: 173–179. doi: 10.1016/0305-0491(94)90063-9

[26] Mundi MS, Shah M, Hurt RT. When is it appropriate to use glutamine in critical illness? Nutr Clin Pract, 2016. 31(4): 445-450. doi: 10.1177/0884533616651318

[27] Wu G, Wu Z, Dai Z, Yang Y, Wang W, Liu C, Wang B, Wang J, Yin Y. Dietary requirements of "nutritionally non-essential amino acids" by animals and humans. Amino Acids, 2013. 44(4): 1107-1113. doi: 10.1007/s00726-012-1444-2.

[28] Xi P, Jiang Z, Zheng C, Lin Y, Wu G. Regulation of protein metabolism by L-glutamine: implications for nutrition and health. Front Biosci, 2011. 16: 578-597. doi: 10.2741/3707

[29] Albrecht J, Sidoryk-Wegrzynowicz M, Zielinska M, Aschner M. Roles of L-glutamine in neurotransmission. Neuron Glia Biology 2010. 6(4): 263–276. doi: 10.1017/S1740925X11000093

[30] Watford M. L-glutamine metabolism and function in relation to proline synthesis and the safety of L-glutamine and proline supplementation. J Nutr, 2008. 138(10): 2003S-2007S. doi: 10.1093/jn/138.10.2003S

[31] Lacey JM, Wilmore DW. Is L-glutamine a conditionally essential amino acid? Nutr Rev, 1990. 48(8): 297-309. DOI: 10.1111/j.1753-4887.1990.tb02967.x

[32] Lobley GE, Hoskin SO, McNeil CJ. L-glutamine in animal science and production. J Nutr, 2001. 131(9 Suppl):2525S-2531S; discussion 2532S-2534S. doi: 10.1093/jn/131.9.2525S

[33] Fürst P, Pogan K, Stehle P. L-glutamine dipeptides in clinical nutrition. Nutrition, 1997. 13(7-8): 731-737. doi: 10.1016/s0899-9007(97)83035-3

[34] Zuhl MN, Lanphere KR, Kravitz L, Mermier CM, Schneider S, Dokladny K, Moseley PL. Effects of oral glutamine supplementation on exercise-induced gastrointestinal permeability and tight junction protein expression. J Appl Physiol, 2014. 116: 183–191. doi: 10.1152/japplphysiol.00646

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

[36] Bertolo RF, Burrin DG. Comparative aspects of tissue L-glutamine and proline metabolism. J Nutr, 2008. 138(10): 2032S-2039S. doi: 10.1093/jn/138.10.2032S

[37] Brasse-Lagnel C, Lavoinne A, Husson A. Control of mammalian gene expression by amino acids, especially L-glutamine. FEBS J, 2009. 276(7): 1826-1844. doi: 10.1111/j.1742-4658.2009.06920.x

[38] Ruth MR, Field CJ. The immune modifying effects of amino acids on gut-associated lymphoid tissue. J Anim Sci Biotechnol, 2013. 4(1): 27. doi: 10.1186/2049-1891-4-27

[39] Miron N, Cristea V. Enterocytes: active cells in tolerance to food and microbial antigens in the gut. Clin Exp Immunol, 2012. 167(3): 405-412. doi: 10.1111/j.1365-2249.2011.04523.x.

[40] MacFie J, McNaught C. L-glutamine and gut barrier function. Nutrition, 2002. 18(5): 433-434. doi: 10.1016/s0899-9007(02)00766-9

[41] Domeneghini C, Di Giancamillo A, Bosi G, Arrighi S. Can nutraceuticals affect the structure of intestinal mucosa? Qualitative and quantitative microanatomy in L-glutamine diet-supplemented weaning piglets. Vet Res Commun, 2006. 30(3): 331-342. doi: 10.1007/s11259-006-3236-1

[42] dos Santos Rd, Viana ML, Generoso SV, Arantes RE, Davisson Correia MI, Cardoso VN. L-glutamine supplementation decreases intestinal permeability and preserves gut mucosa integrity in an experimental mouse model. J Parenter Enteral Nutr, 2010. 34(4): 408-413. doi: 10.1177/0148607110362530

[43] Sukhotnik I, Khateeb K, Mogilner JG, Helou H, Lurie M, Coran AG, Shiloni E. Dietary glutamine supplementation prevents mucosal injury and modulates intestinal epithelial restitution following ischemia-reperfusion injury in the rat. Dig Dis Sci, 2007. 52(6): 1497-1504. doi: 10.1007/s10620-006-9629-8

[44] Mittendorfer B, Volpi E, Wolfe RR. Whole body and skeletal muscle glutamine metabolism in healthy subjects. Am J Physiol Endocrinol Metab, 2001. 280(2):E323-33. doi: 10.1152/ajpendo.2001.280.2.E323

[45] Rogero MM, Tirapegui J, Pedrosa RG, Pires ISSO, Castro IA. Plasma and tissue L-glutamine response to acute and chronic supplementation with L-glutamine and L-alanyl-L-glutamine in rats. Nutr Res, 2004. 24: 261–270. doi.org/10.1016/j.nutres.2003.11.002

[46] Wong AW, Magnuson BA, Nakagawa K, Bursey RG. Oral subchronic and genotoxicity studies conducted with the amino acid, L-glutamine. Food Chem Toxicol, 2011. 49(9): 2096-2102. doi: 10.1016/j.fct.2011.05.023

[47] Urschel KL, Geor RJ, Hanigan MD, Harris PA. Amino acid supplementation does not alter whole-body phenylalanine kinetics in Arabian geldings. J Nutr, 2012. 142(3): 461-469. doi: 10.3945/jn.111.149906.

[48] Urschel KL, Geor RJ, Waterfall HL, Shoveller AK, McCutcheon LJ. Effects of leucine or whey protein addition to an oral glucose solution on serum insulin, plasma glucose and plasma amino acid responses in horses at rest and following exercise. Equine Vet J Suppl, 2010. 38:347-54. doi: 10.1111/j.2042-3306.2010.00179.x.

[49] Manso Filho HC, McKeever KH, Gordon ME, Manso HE, Lagakos WS, Wu G, Watford M. Developmental changes in the concentrations of L-glutamine and other amino acids in plasma and skeletal muscle of the Standardbred foal. J Anim Sci, 2009. 87(8): 2528-2535. doi: 10.2527/jas.2009-1845

[50] Silver M, Fowden AL, Taylor PM, Knox J, Hill CM. Blood amino acids in the pregnant mare and fetus: the effects of maternal fasting and intrafetal insulin. Exp Physiol, 1994. 79(3): 423-433. doi: 10.1113/expphysiol.1994.sp003777

[51] Blikslager AT. Treatment of gastrointestinal ischemic injury. Vet. Clin. North Am. Equine Pract, 2003. 19(3): 715-727. doi: 10.1016/j.cveq.2003.08.004

[52] Wu G. Functional amino acids in growth, reproduction, and health. Adv Nutr, 2010. 1(1): 31-37. doi: 10.3945/an.110.1008

[53] Routledge NB, Harris RC, Harris PA, Naylor JR, Roberts CA. Plasma L-glutamine status in the equine at rest, during exercise and following viral challenge. Equine Vet J Suppl, 1999. 30: 612-616. doi: 10.1111/j.2042-3306.1999.tb05295.x

[54] Jahn P, Liska I, Hanak J, Snow D, Greenhaff P, Dobias P, Kostelecka B, Skalicky J. Effects of exercise and metabolic alkalosis on selected plasma amino acid concentrations in Thoroughbred racehorses. In Equine Exercise Physiology 3, 1991. pp 380-385. ISBN: 9163006677

[55] Robson PJ, Alston TD, Myburgh KH. Prolonged suppression of the innate immune system in the horse following an 80 km endurance race. Equine Vet J, 2003. 35: 133–137. doi: 10.2746/042516403776114144

[56] Lagranha CJ, Levada-Pires AC, Sellitti DF, Procopio J, Curi R, Pithon-Curi TC. The effect of L-glutamine supplementation and physical exercise on neutrophil function. Amino Acids, 2008. 34(3): 337-346. doi: 10.1007/s00726-007-0560-x

[57] Walsh NP, Gleeson M, Shephard RJ, Gleeson M, Woods JA, Bishop NC, Fleshner M, Green C, Pedersen BK, Hoffman-Goetz L, Rogers CJ, Northoff H, Abbasi A, Simon P. Position statement. Part one: Immune function and exercise. Exerc Immunol Rev, 2011. 17: 6-63.

[58] Newsholme P. Why is L-glutamine metabolism important to cells of the immune system in health, postinjury, surgery or infection? J Nutr, 2001. 131 (9 Suppl): 2515S-2522S; discussion 2523S-2524S. doi: 10.1093/jn/131.9.2515S

[59] Newsholme EA, Calder PC. The proposed role of L-glutamine in some cells of the immune system and speculative consequences for the whole animal. Nutrition, 1997. 13(7-8): 728-730. doi: 10.1016/s0899-9007(97)83034-1

[60] Peters LW, Smiet E, de Sain-van der Velden MG, van der Kolk JH. Amino acid utilization by the hindlimb of warmblood horses at rest and following low intensity exercise. Vet Q, 2013. 33(1):20-44. doi: 10.1080/01652176.2013.775833.

[61] Westermann CM, Dorland L, Wijnberg ID, de Sain-van der Velden MG, van Breda E, Barneveld A, de Graaf-Roelfsema E, Keizer HA, van der Kolk JH. Amino acid profile during exercise and training in Standardbreds. Res Vet Sci, 2011. 91(1): 144-149. doi: 10.1016/j.rvsc.2010.08.010

[62] Hackl S, van den Hoven R, Zickl M, Spona J, Zentek J. The effects of short intensive exercise on plasma free amino acids in standardbred trotters. J Anim Physiol Anim Nutr (Berl), 2009. 93(2): 165-173. doi: 10.1111/j.1439-0396.2007.00801.x

[63] Nostell KE, Essén-Gustavsson B, Bröjer JT. Repeated post-exercise administration with a mixture of leucine and glucose alters the plasma amino acid profile in Standardbred trotters. Acta Vet Scand, 2012. 54:7. doi: 10.1186/1751-0147-54-7.

[64] Miller PA, Lawrence LM. The effect of dietary protein level on exercising horses. J Anim Sci, 1988. 66(9): 2185–2192. doi: 10.2527/jas1988.6692185x

[65] Waller A, Lindinger MI. Time course and magnitude of fluid and electrolyte shifts during recovery from high-intensity exercise in Standardbred racehorses. Equine and Comparative Exercise Physiology, 2005. 2(2); 77–87. doi: 10.1079/ECP200557

[66] Harris RC, Harris PA, Routledge NB, Naylor JR, Wilson AM. Plasma L-glutamine concentrations in the horse following feeding and oral L-glutamine supplementation. Equine Vet J Suppl, 2006. 36: 637-642. doi: 10.1111/j.2042-3306.2006.tb05618.x

[67] van den Hoven R, Bauer A, Hackl S, Zickl M, Spona J, Zentek J. A preliminary study on the changes in some potential markers of muscle-cell degradation in sub-maximally exercised horses supplemented with a protein and amino acid mixture. J Anim Physiol Anim Nutr (Berl), 2011. 95(5): 664-675. doi: 10.1111/j.1439-0396.2010.01097.x

[68] Matsui A, Ohmura H, Asai Y, Takahashi T, Hiraga A, Okamura K, Tokimura H, Sugino T, Obitsu T, Taniguchi K. Effects of amino acid and glucose administration following exercise on the turnover of muscle protein in the hind limb femoral region of thoroughbreds. Equine Vet J Suppl, 2006. 36: 611–616. DOI: 10.1111/j.2042-3306.2006.tb05613.x

[69] King N, Suleiman MS. Effect of regular training on the myocardial and plasma concentrations of taurine and alpha-amino acids in thoroughbred horses. Amino Acids, 1998. 15(3): 241-251. doi: 10.1007/bf01318863

[70] Li X, Rezaei R, Li P, Wu G. Composition of amino acids in feed ingredients for animal diets. Amino Acids, 2011. 40(4): 1159-1168. doi: 10.1007/s00726-010-0740-y

[71] Woodward AD, Nielsen BD, Liesman J, Lavin T, Trottier NL. Protein quality and utilization of timothy, oat-supplemented timothy, and alfalfa at differing harvest maturities in exercised Arabian horses. J Anim Sci, 2011. 89(12):4081-92. doi: 10.2527/jas.2010-3825

[72] Johnson RJ, Hart JW. Influence of feeding and fasting on plasma free amino acids in the equine. J Anim Sci, 1974. 38(4): 790-794. doi: 10.2527/jas1974.384790x

[73] Russell MA, Rodiek AV, Lawrence LM. Effect of meal schedules and fasting on selected plasma free amino acids in horses. J Anim Sci, 1986. 63(5): 1428-1431. doi: 10.2527/jas1986.6351428x

[74] Watford M, Reeds PJ. Glutamate metabolism in the gut. Forum Nutr, 2003. 56: 81-82.

[75] Duckworth DH, Madison JB, Calderwood-Mays M, Souba WW. Arteriovenous differences for L-glutamine in the equine gastrointestinal tract. Am J Vet Res, 1992. 53(10): 1864-1867.

[76] Salloum RM, Duckworth D, Madison JB, Souba WW. Characteristics of L-glutamine transport in equine jejunal brush border membrane vesicles. Am J Vet Res, 1993. 54(1): 152-157.

[77] Hintz HF. Digestive physiology of the horse. S Afr Vet Assoc, 1975. 46(1): 13-17.

[78] Merediz EF, Dyer J, Salmon KS, Shirazi-Beechey SP. Molecular characterisation of fructose transport in equine small intestine. Equine Vet J, 2004. 36(6): 532-538. doi: 10.2746/0425164044877378

[79] Cehak A, Burmester M, Geburek F, Feige K, Breves G. Electrophysiological characterization of electrolyte and nutrient transport across the small intestine in horses. J Anim Physiol Anim Nutr (Berlin), 2009. 93(3): 287-294. doi: 10.1111/j.1439-0396.2008.00882.x

[80] Dyer J, Al-Rammahi M, Waterfall L, Salmon KS, Geor RJ, Bouré L, Edwards GB, Proudman CJ, Shirazi-Beechey SP. Adaptive response of equine intestinal Na+/glucose co-transporter (SGLT1) to an increase in dietary soluble carbohydrate. Pflugers Arch, 2009. 458(2): 419-430. doi: 10.1007/s00424-008-0620-4

[81] Rasoamanana R, Darcel N, Fromentin G, Tomé D. Nutrient sensing and signaling by the gut. Proc Nutr Soc, 2012. 71(4): 446-455. doi: 10.1017/S0029665112000110

[82] Lindinger MI, Ecker GL. Gastric emptying, intestinal absorption of electrolytes and exercise performance in electrolyte-supplemented horses. Exp Physiol, 2013. 98(1): 193-206. doi: 10.1113/expphysiol.2012.065185

[83] Woodward AD, Holcombe SJ, Steibel JP, Staniar WB, Colvin C, Trottier NL. Cationic and neutral amino acid transporter transcript abundances are differentially expressed in the equine intestinal tract. J Anim Sci, 2010. 88(3): 1028-1033. doi: 10.2527/jas.2009-2406

[84] Woodward AD, Fan MZ, Geor RJ, McCutcheon LJ, Taylor NP, Trottier NL. Characterization of L-lysine transport across equine and porcine jejunal and colonic brush border membrane. J Anim Sci, 2012. 90(3): 853-862. doi: 10.2527/jas.2011-4210

[85] Blachier F, Boutry C, Bos C, Tomé D. Metabolism and functions of L-glutamate in the epithelial cells of the small and large intestines. Am J Clin Nutr, 2009. 90(3):814S-821S. doi: 10.3945/ajcn.2009.27462S

[86] Lindinger MI, Anderson SC. Seventy day safety assessment of an orally ingested, L-glutamine-containing oat and yeast supplement for horses. Regul Toxicol Pharmacol, 2014. 70(1): 304-311. doi: 10.1016/j.yrtph.2014.07.011

[87] Food and Nutrition Board. Protein and amino acids, Chapter 10. In: Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). A Report of the Panel on Macronutrients, Subcommittees on Upper Reference Levels of Nutrients and Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. 2005. The National Academies Press, 589 – 768.

[88] Shao A, Hathcock JN. Risk assessment for the amino acids taurine, L-glutamine and L-arginine. Regul Toxicol Pharmacol, 2008. 50(3): 376-399. doi: 10.1016/j.yrtph.2008.01.004

[89] Wischmeyer PE. L-glutamine: mode of action in critical illness. Crit Care Med, 2007. 35: S541–S544. doi: 10.1097/01.CCM.0000278064.32780.D3

[90] Ward E, Picton S, Reid U, Thomas D, Gardener C, Smith M, Henderson M, Holden V, Kinsey S, Lewis I, Allgar V. Oral glutamine in paediatric oncology patients: a dose finding study. Eur J Clin Nutr, 2003. 57(1): 31-36. doi: 10.1038/sj.ejcn.1601517

[91] Ziegler TR, Benfell K, Smith RJ, Young LS, Brown E, Ferrari-Baliviera E, Lowe DK, Wilmore DW. Safety and metabolic effects of L-glutamine administration in humans. JPEN J Parenter Enteral Nutr, 1990. 14(4 Suppl): 137S-146S. doi: 10.1177/0148607190014004201

[92] Holecek M. Side effects of long-term L-glutamine supplementation. J Parenter Enteral Nutr, 2013. 37(5): 607-616. doi: 10.1177/0148607112460682.

[93] Wang L, Maher TJ, Wurtman RJ. Oral L-glutamine increases GABA levels in striatal tissue and extracellular fluid. FASEB Journal, 2007. 21: 1227–1232. doi: 10.1096/fj.06-7495com

[94] Borges Dock-Nascimento D, Aguilar-Nascimento JE, Caporossi C, Sepulveda Magalhães Faria M, Bragagnolo R, Caporossi FS, Linetzky Waitzberg D. Safety of oral L-glutamine in the abbreviation of preoperative fasting: a double-blind, controlled, randomized clinical trial. Nutr Hosp, 2011. 26(1): 86-90.

[95] Galera SC, Fechine FV, Teixeira MJ, Coelho ZC, de Vasconcelos RC, de Vasconcelos PR. The safety of oral use of L-glutamine in middle-aged and elderly individuals. Nutrition, 2010 26(4): 375-381. doi: 10.1016/j.nut.2009.05.013

[96] NIH. 2018. http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=cd3fb572-c5b1-43da-aea2-31208985f544#section-8.3; accessed Dec. 30, 2019.

[97] Mastellar SL, Coleman RJ, Urschel KL. Controlled trial of whole body protein synthesis and plasma amino acid concentrations in yearling horses fed graded amounts of lysine. Vet J, 2016. 216: 93-100. doi: 10.1016/j.tvjl.2016.07.007

[98] Miller-Graber PA, Lawrence LM, Kurcz E, Kane R, Bump K, Fisher M, Smith J. The free amino acid profile in the middle gluteal before and after fatiguing exercise in the horse. Equine Vet J, 1990. 22(3): 209-210. doi: 10.1111/j.2042-3306.1990.tb04249.x

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