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Amino acids – Guidelines on Parenteral Nutrition, Chapter 4

Aminosäuren – Leitlinie Parenterale Ernährung, Kapitel 4

Review Article Special Issue

  • J. Stein - Dept. Internal Medicine, University of Frankfurt, Germany
  • H. J. Boehles - Dept. of Paediatrics, Johann-Wolfgang-Goethe University of Frankfurt, Germany
  • I. Blumenstein - Dept. Internal Medicine, University of Frankfurt, Germany
  • C. Goeters - Dept. of Anaesthesiology and Operative Intensive Medicine, University of Munster, Germany
  • R. Schulz - Clinic for Geriatrics, St. Marien-Hospital, Cologne, Germany
  • Working group for developing the guidelines for parenteral nutrition of The German Association for Nutritional Medicine

GMS Ger Med Sci 2009;7:Doc24

doi: 10.3205/000083, urn:nbn:de:0183-0000832

Received: January 14, 2009
Published: November 18, 2009

© 2009 Stein et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Protein catabolism should be reduced and protein synthesis promoted with parenteral nutrion (PN). Amino acid (AA) solutions should always be infused with PN. Standard AA solutions are generally used, whereas specially adapted AA solutions may be required in certain conditions such as severe disorders of AA utilisation or in inborn errors of AA metabolism. An AA intake of 0.8 g/kg/day is generally recommended for adult patients with a normal metabolism, which may be increased to 1.2–1.5 g/kg/day, or to 2.0 or 2.5 g/kg/day in exceptional cases. Sufficient non-nitrogen energy sources should be added in order to assure adequate utilisation of AA. A nitrogen calorie ratio of 1:130 to 1:170 (g N/kcal) or 1:21 to 1:27 (g AA/kcal) is recommended under normal metabolic conditions. In critically ill patients glutamine should be administered parenterally if indicated in the form of peptides, for example 0.3–0.4 g glutamine dipeptide/kg body weight/day (=0.2–0.26 g glutamine/kg body weight/day). No recommendation can be made for glutamine supplementation in PN for patients with acute pancreatitis or after bone marrow transplantation (BMT), and in newborns. The application of arginine is currently not warranted as a supplement in PN in adults. N-acetyl AA are only of limited use as alternative AA sources. There is currently no indication for use of AA solutions with an increased content of glycine, branched-chain AAs (BCAA) and ornithine-α-ketoglutarate (OKG) in all patients receiving PN. AA solutions with an increased proportion of BCAA are recommended in the treatment of hepatic encephalopathy (III–IV).

Keywords: amino acids, branched-chain amino acids (BCAA), dipeptide, amino acid metabolism (first pass)


Ein Proteinkatabolismus soll bei parenteraler Ernährung (PE) vermindert und anabole Stoffwechselprozesse gefördert werden. Standard-Aminosäure (AS)-Lösungen werden empfohlen, falls nicht in Sondersituationen z. B. bei schweren AS-Verwertungsstörungen oder bei angeborenen Stoffwechselstörungen spezifisch adaptierte AS-Lösungen eingesetzt werden müssen. Für erwachsene Patienten in ausgeglichenem Stoffwechselzustand wird eine AS-Zufuhr von 0,8 g/kg/Tag empfohlen, die auf 1,2–1,5 g/kg/Tag oder in Ausnahmefällen auch auf 2,0–2,5 g/kg/Tag gesteigert werden kann. Zur Gewährleistung einer angemessenen Utilisation von AS sollten ausreichend Nicht-Stickstoff-Energieträger zugegeben werden. Das angestrebte Verhältnis zwischen Stickstoff- und Energiezufuhr (Stickstoff-Kalorien-Verhältnis) sollte unter Normalbedingungen 1:100–1:130 (g N:kcal) bzw. 1:16–1:21 (g AS:kcal) betragen. Glutamin sollte parenteral bei kritisch Kranken, sofern indiziert, in Form von Peptiden verabreicht werden, wie z.B. 0,3–0,4 g Glutamin-Dipepetid/kg KG/Tag (entsprechend 0,2–0,26 g Glutamin/kg KG/Tag). Für Patienten mit akuter Pankreatitis, nach Knochenmarkstransplantation sowie für Neugeborene kann derzeit keine Empfehlung für eine Glutaminsupplementierung mit der PE ausgesprochen werden. Der Einsatz von Arginin als Supplement in der PE beim Erwachsenen ist derzeit nicht gerechtfertigt. Den N-azetylierten AS kommen als alternative Aminosäurenquellen zur Zeit nur eine begrenzte Bedeutung zu. Für eine generelle Verwendung von AS-Lösungen mit einem erhöhten Gehalt von Glyzin und verzweigtkettigten AS (VKAS) wie auch für Ornithin-α-Ketoglutarat (OKG) besteht keine gesicherte Indikation. Die Wirksamkeit von AS-Lösungen mit erhöhtem Anteil an VKAS in der Behandlung der hepatischen Enzephalopathie (III–IV) wird empfohlen.

Schlüsselwörter: Aminosäuren, verzweigtkettige Aminosäuren, Dipeptide, Aminosäuremetabolismus

Amino acid intake


An important objective of parenteral nutrition (PN), in addition to meeting energy requirements, is to maintain vital organ structure and function. Protein catabolism should be decreased and protein synthesis promoted.

Amino acids (AA), the building blocks in protein synthesis, are classified as dispensable, indispensable, and conditionally dispensable AA and their precursors (Table 1 [Tab. 1]). Recommended AA supplies with PN are generally based on oral/enteral intake recommendations (Table 2 [Tab. 2]), but data from animal studies [1], [2], [3] and clinical trials [4] point to different AA needs with parenteral and enteral supply.


Indication and contraindication

  • AA should always be infused with PN (A).
  • Contraindications to the infusion of standard AA solutions are inborn errors of AA metabolism (e.g. phenylketonuria, maple syrup urine disease, cystinuria) as well as severe disorders of AA utilisation (e.g. severe liver dysfunction). Specially adapted AA solutions should be used when necessary (A).


AA solutions are an essential part of complete PN for the maintenance of nitrogen homeostasis [5].

Contraindications to the infusion of standard AA solutions are inborn errors of AA metabolism (cf. chapter “Neonatology/Paediatrics” as well as severe disorders of AA utilisation such as severe liver dysfunction (cf. chapters “Gastroenterology” and “Hepatology” or renal disorders (cf. chapter “Parenteral nutrition in patients with renal failure” Specially adapted AA solutions should be used in these situations.


Amino acid solutions

  • None of the presently available AA solutions meet all the physiological requirements of dispensable and indispensable AA.


Crystalline AA solutions used presently in PN contain between 3.5 and 15% of weight as AAs (osmolarity 450 to 1450 mosmol/l) (Table 3 [Tab. 3] and Table 4 [Tab. 4]). None of the currently available solutions provide ideal quantities of indispensable and dispensable AA [6] because of either poor solubility of individual AA (tyrosine, cysteine) or instability in aqueous solutions (e.g. glutamine dissociates into pyroglutamate and ammoniac). Dipeptide solutions, which have recently become available, allow for an improvement in the intravenous administration of larger amounts of some AA (see below) in the form of complete solutions or supplements.


Basic adult requirements

  • An AA intake of 0.8 g/kg/day is recommended for an adult patient on total PN with a normal metabolism and normal organ functions, irrespective of age and sex (B). Depending on metabolic requirements, this can be increased to 1.2–1.5 g/kg/day (A), or to 2.0 or 2.5 g/kg/day (C) in exceptional cases.
  • Sufficient non-nitrogen energy sources should be added in order to guarantee optimum utilisation of AA. A nitrogen calorie ratio between 1:130 and 1:170 (g N/kcal) or 1:21 to 1:27 (g AA/kcal) is recommended under normal metabolic conditions (A).


A recently published meta-analysis of nitrogen balance studies, investigating the protein requirements of healthy adults, has recommended an oral protein intake of 0.8 g/kg/day irrespective of age and sex [5].

As the objective of PN therapy in critically ill patients is to minimise the loss lean body cell mass, the above-mentioned protein requirement for healthy adults should be adjusted according to the severity of the clinical picture. For example, in non-hypercatabolic patients with acute kidney failure or during the polyuric recovery phase after acute kidney failure, a protein intake of 1.0–1.3 g/kg /day is recommended to maintain nitrogen balance [7]. An intake of 1.2–1.5 g/kg/day is recommended in patients with severe acute pancreatitis [8]. The previously suggested upper limit of 1.5 g/kg/day may be exceeded in extremely catabolic, critically ill patients depending on their energy requirements. An intake of up to 2.5 g/kg body weight/day is recommended by some authors in order to achieve a positive nitrogen balance, particularly in burns patients with no kidney or liver insufficiency, as well as in critically ill patients requiring dialysis due to renal insufficiency [9], [10], [11]. An adjustment of the protein intake to >1.5 g/kg body weight/day is also recommended in malnourished patients [12]. The level of intake should generally not exceed an amount allowing for a serum urea value near the upper end of the reference range.

Sufficient non-nitrogen energy sources should be added in order to guarantee the optimum utilisation of AAs [13]. A nitrogen calorie ratio between 1:130 and 1:170 (g N/kcal) or 1:21 to 1:27 (g AA/kcal) is recommended under normal metabolic conditions (A). In contrast to data on oral/enteral protein intake, there are no sufficient data to determine the optimal ratio of indispensable/total AA (E/T ratio) in PN.

Conditionally indispensable amino acids

New studies are increasingly questioning the conventional classification of indispensable and dispensable AA in clinical nutrition. Numerous data point out that some of the so-called dispensable AAs are conditionally indispensable in adults under certain medical situations [14], and therefore, should be supplied [15].


In catabolic illnesses (e.g. elective surgery, trauma, pancreatitis, burns, high-dosage chemotherapy), massive intracellular glutamine deficiency occurs in muscles. Many studies have highlighted the fact that in these illnesses glutamine is released from muscle tissue and lungs and is made available for other organs (e.g. intestines, kidney) and immune cells. Thus, glutamine is the most important AA for nitrogen transport between organs and organ systems.

  • Critically ill patients receiving no enternal nutrition (including burns and trauma patients) should receive a sufficient amount of glutamine dipeptides (0.3–0.4 g glutamine dipeptide/kg body weight/day = 0.2–0.26 g glutamine/kg body weight/day) in PN (A).
  • No recommendation can be made for glutamine supplementation in patients with acute pancreatitis due to the lack of data (C).
  • No recommendation can be made for glutamine supplementaion in PN for patients after bone marrow transplantation (BMT), and in newborns, due to the availability of limited and inconsistent data (C).


Twelve prospective randomised studies and 2 meta-analyses [16], [17] have established the efficacy of glutamine-containing PN in both surgical [18], [19], [20], [21], [22], [23], [24] and other critically ill patients [25], [26], [27], [28]. Administration of glutamine resulted in a dose-dependent reduction in infection-related complications as well as length of hospital stay in critically ill patients who had undergone surgery. Likewise, in medical intensive care patients there was a significant reduction in complications and mortality.

Although, two randomised studies have been published [29], [30] on the effect of glutamine administration on patients with acute pancreatitis, no recommendation can be made due to the small number of patients included in the study. In patients after bone marrow transplantation, no consensus can be reached regarding the administration of glutamine [31], [32], [33].

  • When indicated, glutamine should be administered parenterally, in the form of peptides (A).


Commercially available AA solutions contain only small amounts of cysteine, tyrosine or glutamine due to their low solubility or instability. These AAs are regarded as semi-essential in certain situations. Recently, di- and tripeptides of cysteine, glutamine and tyrosine have been synthesised that are hydolysed rapidly to provide the respective AA.

Glutamine-containing parenteral solutions must be freshly prepared, under strict aseptic conditions at 4°C due to their low solubility in aqueous solutions and their tendency to be degraded to pyroglutamate, which involves a release of ammonia. The concentration of glutamine in the aqueous parenteral solution should not exceed 1–1.5% [w/v] in order to prevent precipitation. The amount of glutamine that can be administered is therefore limited, as large amounts of fluid have to be infused to overcome the low solubility of glutamine.


  • The application of arginine is not currently warranted as a supplement in PN in adults (C).


There are only a few isolated studies on the parenteral use of arginine in patients. In critically ill patients, arginine has a favourable effect on the function of immune cells and on the progression of wound healing [34], [35]. Arginine plays a key role in nitrogen homeostasis, in the formation of creatine and the polyamines, and is the most important substrate in the formation of nitric oxide (NO). In burn patients, for example, a significant drop in serum arginine concentration was observed due to an increased synthesis of ornithine (starting substrate of polyamine synthesis) [34], [35]. An increase in arginine intake from 5% to 7% of total AA may result in immunomodulatory effects [34], [35], [36]. Routine parenteral supplementation of arginine is not recommended due to the insufficient data on safety and efficacy.

N-acetyl amino acids

  • N-acetyl AA are metabolised to a limited extent in humans and are, therefore, only of limited use as alternative AA sources in clinical nutrition at the present time (B).
  • N-acetyl cysteine is recommended to prevent contrast agent (CA)-induced nephropathy (A).


Initial studies on animals provided convincing data that the soluble and stable N-acetyl AA, i.e. acetyl cysteine, acetyl tyrosine and acetyl glutamine, are effectively deacetylised in vivo and the released AA are well metabolised [37]. Subsequent studies on humans, however, did not support this data. In humans, 50% of the substrates are excreted unchanged in the urine. Compared to dipeptides, the half-life of acetyl cysteine after intravenous administration is approximately 40 times higher [38], [39]. However, effectiveness of N-acetyl cysteine (600 mg intravenously 12 hours before and 12 hours after administration of CA) in prevention of renal failure after CA administration has been demonstrated in many studies [40], [41].

Glycine, branched-chain amino acids, ornithine-alpha-ketoglutarate

  • There is currently no indication for use of AA solutions with an increased content of glycine, branched-chain AAs (BCAA) and ornithine-α-ketoglutarate (OKG) in all patients receiving PN (I).
  • AA solutions with an increased proportion of BCAA are recommended in the treatment of hepatic encephalopathy (III–IV) as they are effective in alleviating the encephalopathy (A).


The dispensable, soluble AA glycine is the only naturally occurring AA which is neither chirally nor optically active. It is an essential part of scleroproteins as well as an intermediate in the biosynthesis of porphyrins, purines, creatinine and glutathione. Glycine serves as a flexible bond for proteins, which is necessary for helix formation, and acts as an extracellular signal protein. It is cytoprotective in ischemic insults, hypoxia and reperfusion damage [42]. Orally administered glycine in conjunction with glutamine serves to repair cells, the metabolic adaption, and protects intestinal mucosa after intestinal resection [43], [44]. Administration of high dose glycine with glutamine resulted in a good compatibility and uptake in patients with polytrauma [45].

The use of parenteral AA solutions, which are concentrated with BCAA, is well-known. BCAA supplementation is used in multiple conditions such as liver disorders (especially hepatic encephalopathy), sepsis, trauma, disorders of gastric motility, and the prevention of failure of the respiratory musculature during artificial respiration.

The effectiveness of BCAA in the treatment of hepatic encephalopathy was tested in seven controlled studies, where the individual results were contradictory, but in meta-analysis showed an improvement in encephalopathy. However, no benefit was observed in the survival rate [46].

Until to date, there are only small randomised studies that have investigated the use of AA solutions with an increased proportion of BCAA, in critically ill patients and demonstrated an improvement in clinical status [47], [48], [49], [50], The small number of patients in these studies does not justify a general recommendation.

OKG consists of one molecule of α-ketoglutarate (AKG) and 2 molecules of ornithine. After intravenous administration, it dissociates into the two parts in blood [51]. OKG is well tolerated and is associated with the stimulated release of insulin and growth hormone, and it serves as a substrate for polyamine synthesis. The components of OKG participate in glutamine biosynthesis. In small studies, intravenous administration of OKG in post-operative and critically ill patients results in protein conservation, stimulation of protein synthesis in the muscles, and reduction in degradation of the muscular glutamine pool [52], [53], [54].


This article is part of the publication of the Guidelines on Parenteral Nutrition from the German Society for Nutritional Medicine (overview and corresponding address under

English version edited by Sabine Verwied-Jorky, Rashmi Mittal and Berthold Koletzko, Univ. of Munich Medical Centre, Munich, Germany.


Bertolo RF, Chen CZ, Law G, Pencharz PB, Ball RO. Threonine requirement of neonatal piglets receiving total parenteral nutrition is considerably lower than that of piglets receiving an identical diet intragastrically. J Nutr. 1998;128(10):1752-9.
Elango R, Pencharz PB, Ball RO. The branched-chain amino acid requirement of parenterally fed neonatal piglets is less than the enteral requirement. J Nutr. 2002;132(10):3123-9.
Shoveller AK, Brunton JA, Pencharz PB, Ball RO. The methionine requirement is lower in neonatal piglets fed parenterally than in those fed enterally. J Nutr. 2003;133(5):1390-7.
Wykes LJ, Ball RO, Menendez CE, Ginther DM, Pencharz PB. Glycine, leucine, and phenylalanine flux in low-birth-weight infants during parenteral and enteral feeding. Am J Clin Nutr. 1992;55(5):971-5.
Rand WM, Pellett PL, Young VR. Meta-analysis of nitrogen balance studies for estimating protein requirements in healthy adults. Am J Clin Nutr. 2003;77(1):109-27.
Brunton JA, Ball RO, Pencharz PB. Current total parenteral nutrition solutions for the neonate are inadequate. Curr Opin Clin Nutr Metab Care. 2000;3(4): 299-304. DOI: 10.1097/00075197-200007000-00010 External link
Druml W. Nutritional management of acute renal failure. Am J Kidney Dis. 2001;37(1 Suppl 2):S89-94. DOI: 10.1053/ajkd.2001.20757 External link
Meier R, Beglinger C, Layer P, Gullo L, Keim V, Laugier R, Friess H, Schweitzer M, Macfie J; ESPEN Consensus Group. ESPEN guidelines on nutrition in acute pancreatitis. European Society of Parenteral and Enteral Nutrition. Clin Nutr 2002;21(2):173-83. DOI: 10.1054/clnu.2002.0543 External link
Dickerson RN. Estimating energy and protein requirements of thermally injured patients: art or science? Nutrition. 2002;18(5):439-42. DOI: 10.1016/S0899-9007(01)00806-1 External link
Scheinkestel CD, Kar L, Marshall K, Bailey M, Davies A, Nyulasi I, Tuxen DV. Prospective randomized trial to assess caloric and protein needs of critically Ill, anuric, ventilated patients requiring continuous renal replacement therapy. Nutrition. 2003;19(11-12):909-16. DOI: 10.1016/S0899-9007(03)00175-8 External link
Scheinkestel CD, Adams F, Mahony L, Bailey M, Davies AR, Nyulasi I, Tuxen DV. Impact of increasing parenteral protein loads on amino acid levels and balance in critically ill anuric patients on continuous renal replacement therapy. Nutrition. 2003;19(9):733-40. DOI: 10.1016/S0899-9007(03)00107-2 External link
Hoffer LJ. Protein and energy provision in critical illness. Am J Clin Nutr. 2003;78(5):906-11.
Shaw JH, Wildbore M, Wolfe RR. Whole body protein kinetics in severely septic patients; the response to glucose infusion and total parenteral nutrition. Ann Surg. 1987;205(3):288-94.
Reeds PJ. Dispensable and indispensable amino acids for humans. J Nutr. 2000;130(7):1835S-40S.
Obled C, Papet I, Breuillé D. Metabolic bases of amino acid requirements in acute diseases. Curr Opin Clin Nutr Metab Care. 2002;5(2):189-97. DOI: 10.1097/00075197-200203000-00012 External link
Heyland DK, Dhaliwal R, Drover JW, Gramlich L, Dodek P. Canadian clinical practice guidelines for nutrition support in mechanically ventilated, critically ill adult patients. JPEN J Parenter Enteral Nutr. 2003;27(5):355-73. DOI: 10.1177/0148607103027005355 External link
Novak F, Heyland DK, Avenell A, Drover JW, Su X. Glutamine supplementation in serious illness: a systematic review of the evidence. Crit Care Med. 2002;30(9):2022-9. DOI: 10.1097/00003246-200209000-00011 External link
Jacobi CA, Ordemann J, Zuckermann H, Döcke W, Volk HD, Müller JM. Einfluss von Alanyl-Glutamin bei der postoperativen totalen parenteralen Ernahrung auf die Morbiditat unter besonderer Berucksichtigung der Immunfunktion: Erste Ergebnisse einer prospektiv randomisierten Studie [The influence of alanyl-glutamine on immunologic functions and morbidity in postoperative total parenteral nutrition. Preliminary results of a prospective randomized trial]. Zentralbl Chir. 1999;124(3):199-205.
Jian ZM, Cao JD, Zhu XG, Zhao WX, Yu JC, Ma EL, Wang XR, Zhu MW, Shu H, Liu YW. The impact of alanyl-glutamine on clinical safety, nitrogen balance, intestinal permeability, and clinical outcome in postoperative patients: a randomized, double-blind, controlled study of 120 patients. JPEN J Parenter Enteral Nutr. 1999;23(5 Suppl):S62-6.
Karwowska KA, Dworacki G, Trybus M, Zeromski J, Szulc R. Influence of glutamine-enriched parenteral nutrition on nitrogen balance and immunologic status in patients undergoing elective aortic aneurysm repair. Nutrition. 2001;17(6):475-8. DOI: 10.1016/S0899-9007(01)00537-8 External link
Mertes N, Schulzki C, Goeters C, Winde G, Benzing S, Kuhn KS, Van Aken H, Stehle P, Fürst P. Cost containment through L-alanyl-L-glutamine supplemented total parenteral nutrition after major abdominal surgery: a prospective randomized double-blind controlled study. Clin Nutr. 2000;19(6):395-401. DOI: 10.1054/clnu.2000.0142 External link
Morlion BJ, Stehle P, Wachtler P, Siedhoff HP, Köller M, König W, Fürst P, Puchstein C. Total parenteral nutrition with glutamine dipeptide after major abdominal surgery: a randomized, double-blind, controlled study. Ann Surg. 1998;227(2):302-8. DOI: 10.1097/00000658-199802000-00022 External link
Neri A, Mariani F, Piccolomini A, Testa M, Vuolo G, Di Cosmo L. Glutamine-supplemented total parenteral nutrition in major abdominal surgery. Nutrition. 2001;17(11-12):968-9. DOI: 10.1016/S0899-9007(01)00693-1 External link
O'Riordain MG, Fearon KC, Ross JA, Rogers P, Falconer JS, Bartolo DC, Garden OJ, Carter DC. Glutamine-supplemented total parenteral nutrition enhances T-lymphocyte response in surgical patients undergoing colorectal resection. Ann Surg. 1994;220(2):212-21.
Goeters C, Wenn A, Mertes N, Wempe C, Van Aken H, Stehle P, Bone HG. Parenteral L-alanyl-L-glutamine improves 6-month outcome in critically ill patients. Crit Care Med. 2002;30(9):2032-7. DOI: 10.1097/00003246-200209000-00013 External link
Griffiths RD, Jones C, Palmer TE. Six-month outcome of critically ill patients given glutamine-supplemented parenteral nutrition. Nutrition. 1997;13(4):295-302.
Powell-Tuck J, Jamieson CP, Bettany GE, Obeid O, Fawcett HV, Archer C, Murphy DL. A double blind, randomised, controlled trial of glutamine supplementation in parenteral nutrition. Gut. 1999;45(1):82-8.
Wischmeyer PE, Lynch J, Liedel J, Wolfson R, Riehm J, Gottlieb L, Kahana M. Glutamine administration reduces Gram-negative bacteremia in severely burned patients: a prospective, randomized, double-blind trial versus isonitrogenous control. Crit Care Med. 2001;29(11):2075-80. DOI: 10.1097/00003246-200111000-00006 External link
de Beaux AC, O'Riordain MG, Ross JA, Jodozi L, Carter DC, Fearon KC. Glutamine-supplemented total parenteral nutrition reduces blood mononuclear cell interleukin-8 release in severe acute pancreatitis. Nutrition. 1998;14(3):261-5. DOI: 10.1016/S0899-9007(97)00477-2 External link
Ockenga J, Borchert K, Rifai K, Manns MP, Bischoff SC. Effect of glutamine-enriched total parenteral nutrition in patients with acute pancreatitis. Clin Nutr. 2002;21(5):409-16. DOI: 10.1054/clnu.2002.0569 External link
Muscaritoli M, Grieco G, Capria S, Iori AP, Rossi FF. Nutritional and metabolic support in patients undergoing bone marrow transplantation. Am J Clin Nutr. 2002;75(2):183-90.
Pytlik R, Benes P, Patorková M, Chocenská E, Gregora E, Procházka B, Kozák T. Standardized parenteral alanyl-glutamine dipeptide supplementation is not beneficial in autologous transplant patients: a randomized, double-blind, placebo controlled study. Bone Marrow Transplant. 2002;30(12):953-61. DOI: 10.1038/sj.bmt.1703759 External link
Scheid C, Hermann K, Kremer G, Holsing A, Heck G, Fuchs M, Waldschmidt D, Herrmann HJ, Söhngen D, Diehl V, Schwenk A. Randomized, double-blind, controlled study of glycyl-glutamine-dipeptide in the parenteral nutrition of patients with acute leukemia undergoing intensive chemotherapy. Nutrition. 2004 20(3):249-54. DOI: 10.1016/j.nut.2003.11.018 External link
Yu YM, Ryan CM, Castillo L, Lu XM, Beaumier L, Tompkins RG, Young VR. Arginine and ornithine kinetics in severely burned patients: increased rate of arginine disposal. Am J Physiol Endocrinol Metab. 2001;280(3):E509-17.
Wu G, Meininger CJ, Knabe DA, Bazer FW, Rhoads JM. Arginine nutrition in development, health and disease. Curr Opin Clin Nutr Metab Care. 2000;3(1):59-66. DOI: 10.1097/00075197-200001000-00010 External link
Evoy D, Lieberman MD, Fahey TJ 3rd, Daly JM. Immunonutrition: the role of arginine. Nutrition. 1998;14(7-8):611-7. DOI: 10.1016/S0899-9007(98)00005-7 External link
Neuhäuser M, Bässler KH. Die biologische Verfugbarkeit von Glutamin aus N-Acetyl-L-Glutamin bei intravenoser Verabreichung; Untersuchungen an der Ratte. [Biological availability of glutamine from N-acetyl-L-glutamine in intravenous administration. Studies in the rat]. Infusionsther Klin Ernahr. 1986;13(6):292-6.
Druml W, Lochs H, Roth E, Hübl W, Balcke P, Lenz K. Utilization of tyrosine dipeptides and acetyltyrosine in normal and uremic humans. Am J Physiol. 1991;260(2 Pt 1):E280-5.
Magnusson I, Ekman L, Wångdahl M, Wahren J. N-acetyl-L-tyrosine and N-acetyl-L-cysteine as tyrosine and cysteine precursors during intravenous infusion in humans. Metabolism. 1989;38(10):957-61. DOI: 10.1016/0026-0495(89)90005-X External link
Birck R, Krzossok S, Markowetz F, Schnulle P, van der Woude FJ, Braun C. Acetylcysteine for prevention of contrast nephropathy: meta-analysis. Lancet. 2003;362(9384):598-603. DOI: 10.1016/S0140-6736(03)14189-X External link
Tepel M, van der Giel M, Schwarzfeld C, Laufer U, Liermann D, Zidek W. Prevention of radiographic-contrast-agent-induced reductions in renal function by acetylcysteine. N Engl J Med. 2000;343(3):180-4. DOI: 10.1056/NEJM200007203430304 External link
Hall JC. Glycine. JPEN J Parenter Enteral Nutr. 1998;22(6):393-8. DOI: 10.1177/0148607198022006393 External link
Prabhu R, Thomas S, Balasubramanian KA. Oral glutamine attenuates surgical manipulation-induced alterations in the intestinal brush border membrane. J Surg Res. 2003;115(1):148-56. DOI: 10.1016/S0022-4804(03)00212-9 External link
Weingartmann G, Fridrich P, Mauritz W, Götzinger P, Mittlböck M, Germann P, Karner J, Roth E. Safety and efficacy of increasing dosages of glycyl-glutamine for total parenteral nutrition in polytrauma patients. Wien Klin Wochenschr. 1996;108(21):683-8.
Ziegler TR, Evans ME, Fernández-Estívariz C, Jones DP. Trophic and cytoprotective nutrition for intestinal adaptation, mucosal repair, and barrier function. Annu Rev Nutr. 2003;23:229-61. DOI: 10.1146/annurev.nutr.23.011702.073036 External link
Naylor CD, O'Rourke K, Detsky AS, Baker JP. Parenteral nutrition with branched-chain amino acids in hepatic encephalopathy: A meta-analysis. Gastroenterology. 1989;97(4):1033-42.
Freund HR, Hanani M. The metabolic role of branched-chain amino acids. Nutrition. 2002;18(3):287-8. DOI: 10.1016/S0899-9007(01)00740-7 External link
Fürst P. New developments in glutamine delivery. J Nutr. 2001;131(9 Suppl):2562S-8S.
García-de-Lorenzo A, Ortíz-Leyba C, Planas M, Montejo JC, Núñez R, Ordóñez FJ, Aragón C, Jiménez FJ. Parenteral administration of different amounts of branch-chain amino acids in septic patients: clinical and metabolic aspects. Crit Care Med. 1997;25(3):418-24. DOI: 10.1097/00003246-199703000-00008 External link
Wang XY, Li N, Gu J, Li WQ, Li JS. The effects of the formula of amino acids enriched BCAA on nutritional support in traumatic patients. World J Gastroenterol. 2003;9(3):599-602.
Cynober L. Ornithine alpha-ketoglutarate in nutritional support. Nutrition. 1991;7(5):313-22.
Coudray-Lucas C, Le Bever H, Cynober L, De Bandt JP, Carsin H. Ornithine alpha-ketoglutarate improves wound healing in severe burn patients: a prospective randomized double-blind trial versus isonitrogenous controls. Crit Care Med. 2000;28(6):1772-6. DOI: 10.1097/00003246-200006000-00012 External link
Hammarqvist F, Wernerman J, von der Decken A, Vinnars E. Alpha-ketoglutarate preserves protein synthesis and free glutamine in skeletal muscle after surgery. Surgery. 1991;109(1):28-36.
Wernerman J, Hammarkvist F, Ali MR, Vinnars E. Glutamine and ornithine-alpha-ketoglutarate but not branched-chain amino acids reduce the loss of muscle glutamine after surgical trauma. Metabolism. 1989;38(8 Suppl 1):63-6. DOI: 10.1016/0026-0495(89)90144-3 External link
Deutsche Gesellschaft für Ernährung, Österreichische Gesellschaft für Ernährung, Schweizerische Gesellschaft für Ernährungsforschung, Schweizerische Vereinigung für Ernährung (D-A-CH). Referenzwerte für die Nährstoffzufuhr. Frankfurt: Umschau Braus GmbH; 2000.