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Colosimo S, Bertoli S, Saffioti F. Use of Branched-Chain Amino Acids as a Potential Treatment for Improving Nutrition-Related Outcomes in Advanced Chronic Liver Disease. Nutrients 2023; 15:4190. [PMID: 37836474 PMCID: PMC10574343 DOI: 10.3390/nu15194190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/15/2023] Open
Abstract
Advanced chronic liver disease (ACLD) represents a complex and multifactorial clinical entity characterized by liver dysfunction and associated complications. In recent years, the significance of nutritional status in ACLD prognosis has gained considerable attention. This review article delves into the multifactorial pathogenesis of malnutrition in ACLD and its profound consequences for health outcomes. We explore the clinical implications of secondary sarcopenia in ACLD and highlight the critical relevance of frailty in both decompensated and compensated ACLD. A specific focus of this review revolves around branched-chain amino acids (BCAAs) and their pivotal role in managing liver disease. We dissect the intricate relationship between low Fischer's ratio and BCAA metabolism in ACLD, shedding light on the molecular mechanisms involved. Furthermore, we critically evaluate the existing evidence regarding the effects of BCAA supplementation on outcomes in ACLD patients, examining their potential to ameliorate the nutritional deficiencies and associated complications in this population.
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Affiliation(s)
- Santo Colosimo
- School of Nutrition Science, University of Milan, 20133 Milan, Italy
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, 20133 Milan, Italy
| | - Simona Bertoli
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, 20133 Milan, Italy
- Laboratory of Clinical Studies on Obesity, Istituto Auxologico Italiano IRCCS, 20145 Milan, Italy
| | - Francesca Saffioti
- Oxford Liver Unit, Department of Gastroenterology and Hepatology, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK;
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Ooi PH, Gilmour SM, Yap J, Mager DR. Effects of branched chain amino acid supplementation on patient care outcomes in adults and children with liver cirrhosis: A systematic review. Clin Nutr ESPEN 2018; 28:41-51. [PMID: 30390892 DOI: 10.1016/j.clnesp.2018.07.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 07/27/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS Malnutrition is highly prevalent in chronic liver disease (CLD) due to alterations in nutrient utilization, malabsorption and poor intake. Low serum concentrations of branched chain amino acids (BCAA) in the presence of elevated aromatic acid concentrations is commonly observed in adult and children with liver cirrhosis and is associated with malnutrition and other adverse patient outcomes. The efficacy of BCAA supplementation has not been well established in adults and children with CLD. The purpose of this review was to critically evaluate the literature regarding the impact of BCAA supplementation related to changes in body composition, muscle strength, liver biomarkers, medical and hepatic complications (hepatic encephalopathy (HE), ascites, edema) and patient care outcomes (event free survival, health related quality of life, length of hospitalization). METHODS A total of 40 articles retrieved from PubMed or Web of Science databases (1989-2017) were included. RESULTS BCAA supplementation may be beneficial in improving muscle strength, ascites and edema with potential clinically significant improvements in HE in adult liver patients. In children, limited data have shown that BCAA supplementation may exert favourable effects on weight, fat mass, fat free mass and serum albumin level. CONCLUSIONS Heterogeneity of study findings attributed to variability in BCAA dose (total, relative proportions), duration, disease severity and lack of uniformity in tools used for assessing patient outcomes limit overall conclusions. Longitudinal studies examining the efficacy of BCAA supplementation as a therapeutic treatment of malnutrition in chronic liver disease is warranted.
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Affiliation(s)
- P H Ooi
- Department of Agricultural, Food & Nutritional Sciences, University of Alberta, Canada
| | - S M Gilmour
- Department of Pediatrics, University of Alberta, Canada; Division of Pediatric Gastroenterology & Nutrition/Transplant Services, The Stollery Children's Hospital, Alberta Health Services, Edmonton, Alberta, Canada
| | - J Yap
- Department of Pediatrics, University of Alberta, Canada; Division of Pediatric Gastroenterology & Nutrition/Transplant Services, The Stollery Children's Hospital, Alberta Health Services, Edmonton, Alberta, Canada
| | - D R Mager
- Department of Agricultural, Food & Nutritional Sciences, University of Alberta, Canada; Department of Pediatrics, University of Alberta, Canada.
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Suo H, Sun P, Wang C, Peng D, Zhao X. Apoptotic effects of insect tea in HepG2 human hepatoma cells. CYTA - JOURNAL OF FOOD 2016. [DOI: 10.1080/19476337.2015.1076521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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de Groof F, Huang L, van Vliet I, Voortman GJ, Schierbeek H, Roksnoer LCW, Vermes A, Chen C, Huang Y, van Goudoever JB. Branched-chain amino acid requirements for enterally fed term neonates in the first month of life. Am J Clin Nutr 2014; 99:62-70. [PMID: 24284437 DOI: 10.3945/ajcn.112.038927] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Knowledge of essential amino acid requirements in infants is important because excessive intake of protein can lead to increased long-term morbidity such as obesity. A deficient intake may lead to suboptimal growth and impaired neurodevelopment. The current recommended branched-chain amino acid requirements in infants aged 0-1 mo are based on the amino acid content of human milk. OBJECTIVE We quantified the requirements for isoleucine, leucine, and valine for term neonates by using the indicator amino acid oxidation method with [1-(13)C]phenylalanine as the indicator. DESIGN Fully enterally fed term infants received randomly graded amounts of isoleucine (5-216 mg · kg(-1) · d(-1)), leucine (5-370 mg · kg(-1) · d(-1)), or valine (5-236 mg · kg(-1) · d(-1)) as part of an elemental formula. Data are expressed as means ± SDs. RESULTS Eighty-three Asian, term neonates (mean ± SD birth weight: 3.3 ± 0.4 kg; gestational age: 39.4 ± 1.3 wk) were studied at a postnatal age of 13 ± 5 d. Mean requirements for isoleucine, leucine, and valine (measured in boys only) were 105 mg · kg(-1) · d(-1) (r(2) = 0.61, P < 0.001), 140 mg · kg(-1) · d(-1) (r(2) = 0.26, P < 0.01), and 110 mg · kg(-1) · d(-1) (r(2) = 0.35, P = 0.001), respectively. CONCLUSIONS Current human milk-based recommendations for isoleucine and valine in term infants aged 0-1 mo are correct. However, the current recommendation for leucine (166 mg · kg(-1) · d(-1)) is higher than the mean requirement of 140 mg · kg(-1) · d(-1) that we determined in this study. This trial was registered at www.trialregister.nl as NTR1610.
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Affiliation(s)
- Femke de Groof
- Department of Pediatrics, Emma's Children's Hospital, Academic Medical Center, Amsterdam, Netherlands (FdG, JBvG, and HS); the Department of Pediatrics, VU University Medical Center, Amsterdam, Netherlands (JBvG, LH, and IvV); the Division of Neonatology, Erasmus Medical Center, Sophia Children's Hospital, Rotterdam, Netherlands (GJV and LCWR); the Hospital Pharmacy, Erasmus Medical Center, Rotterdam, Netherlands (AV); and the Division of Neonatology (CC) and the Department of Gastro-Enterology (YH), Fudan Children's Hospital, Shanghai, China
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Pencharz PB, Elango R, Ball RO. An approach to defining the upper safe limits of amino acid intake. J Nutr 2008; 138:1996S-2002S. [PMID: 18806114 DOI: 10.1093/jn/138.10.1996s] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The existing data on the safe upper limits of amino acid intake in humans is essentially observational; how much do individuals ingest and what side effects do they have? There are numerous studies in humans comparing the effects of high doses of amino acids given as protein bound vs. as free amino acids. These studies have shown that protein-bound amino acids have much less effect on plasma levels of the test amino acid, because protein intake stimulates protein synthesis as another sink for the increased amino acid intake. In practice, the highest amino acid intakes occur with free amino acid supplements that may be ingested by athletes who believe that the amino acids will benefit them in training and/or performance. Previously, in a piglet study, we were able to define the point at which maximal phenylalanine oxidation occurred, above which plasma phenylalanine concentration and body balance rose exponentially. We regard this value of maximal disposal (oxidation) of an amino acid as one metabolic marker of the upper limit of intake. Recently, others have demonstrated a similar maximal oxidation rate for leucine in rats. Based on these experimental data and the paucity of published human data in controlled experiments, we think that a systematic approach needs to be undertaken to define the maximal oxidation rate for all dietary indispensable amino acids and other amino acids that may be ingested in excess by humans. We believe that this will provide a rational basis to begin to define the upper limits of tolerance for dietary amino acids. However, some amino acids, such as threonine and methionine, will be more difficult to study, because they have more than 1 route of disposal or very complex metabolic regulation, in which case defining their upper limits will be more multifaceted.
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Affiliation(s)
- Paul B Pencharz
- Research Institute, Hospital for Sick Children, M5G 1X8 Toronto, Ontario, Canada.
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Mager DR, Wykes LJ, Roberts EA, Ball RO, Pencharz PB. Effect of orthotopic liver transplantation (OLT) on branched-chain amino acid requirement. Pediatr Res 2006; 59:829-34. [PMID: 16641206 DOI: 10.1203/01.pdr.0000219302.21321.87] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Little is known regarding the impact of liver transplantation on amino acid requirements in children. Since plasma levels of the branched-chain amino acids (BCAA) are decreased in the presence of normal levels of the aromatic amino acids after liver transplantation, normalization of hepatic function may not fully correct changes in BCAA metabolism that occur in the pretransplant period. The goal of the present study was to determine total BCAA requirements of children following liver transplantation. The requirement of total BCAA was determined using indicator amino acid oxidation (IAAO) in five clinically stable children (5.7 +/- 3.5 y, mean +/- SD) 1-8 y post liver transplantation. Children received in random order 6 graded intakes of total BCAA. Individual BCAA in the test diet were provided in the same proportions as present in egg protein to minimize the potential interactive effects of individual BCAA on assessment of requirement. Total BCAA requirement was determined by measuring the oxidation of L-[1-13C] phenylalanine to 13CO2 [F13CO2 in micromol/kg/h], after a primed, continuous infusion of the tracer and using a two-phase linear regression crossover regression analysis. The estimated average requirement and the upper limit of the 95% CI for total BCAA in children who have undergone liver transplantation were 172 and 206 mg/kg/d), respectively. Total BCAA requirement in children who have undergone orthotopic liver transplantation (OLT) remain increased in the post-liver transplant period when compared with healthy school aged children, but is decreased when compared with children with mild-moderate chronic cholestatic (MCC) liver disease.
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Affiliation(s)
- Diana R Mager
- Department of Nutritional Sciences, University of Toronto, The Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G IX8
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Mager DR, Wykes LJ, Roberts EA, Ball RO, Pencharz PB. Branched-chain amino acid needs in children with mild-to-moderate chronic cholestatic liver disease. J Nutr 2006; 136:133-9. [PMID: 16365072 DOI: 10.1093/jn/136.1.133] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Protein-energy malnutrition is prevalent in children with chronic cholestatic liver disease. Supplementation of branched-chain amino acids (BCAA) in infants and children with chronic liver disease has been associated with significant improvement in growth and nitrogen balance, suggesting that BCAA requirements are increased in chronic liver disease. The goal of the present study was to determine the total BCAA requirement in children with mild-to-moderate chronic cholestatic (MCC) liver disease using indicator amino acid oxidation (IAAO). Total BCAA requirements were determined in 6 children (6.3 +/- 3.7 y, mean +/- SD) with MCC liver disease. Children were randomly assigned to receive 7 graded intakes of total BCAA. Individual BCAA in the test diet were provided in the same proportions as those present in egg protein to minimize the potential interactive effects of individual BCAA on assessment of requirement. The total BCAA requirement was determined by measuring the oxidation of l-[1-13C] Phe to 13CO2 [F13CO2 in micromol/(kg x h)], after a primed, continuous oral administration of the tracer and using a 2-phase linear regression crossover regression analysis. The estimated mean requirement and the upper limit of the 95% CI for total BCAA establishing using the IAAO in children with MCC liver disease were 209 and 272 mg/(kg x d), respectively. Total BCAA estimated average requirements using the IAAO were significantly higher than mean requirements established previously for healthy children (P < 0.05).
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Affiliation(s)
- Diana R Mager
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada
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Kurpad AV, Regan MM, Raj T, Gnanou JV. Branched-chain amino acid requirements in healthy adult human subjects. J Nutr 2006; 136:256S-63S. [PMID: 16365094 DOI: 10.1093/jn/136.1.256s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
There is now an expanding body of evidence to recommend, in the case of adult humans, the use of revised indispensable amino acid requirement values; these are approximately 2 to 3 times higher than the current international recommendations. The earlier methodologies for determining amino acid requirements, based on nitrogen balance, were criticized because of their design and the associated high energy intakes. The 1985 World Health Organization/Food & Agriculture Organization/United Nations University requirement for leucine has been demonstrated to be too low by short- and long-term (24-h) tracer-derived estimates of leucine oxidation and balance. The best values for leucine requirements come from 24-h direct amino acid oxidation (DAAO) and direct amino acid balance (DAAB) studies. Finally, we also collated all available data from studies on fed-state leucine oxidation with an adequate dietary adaptation period to assess the inflection on the leucine oxidation-leucine intake curve. The mean requirements for leucine, valine, and isoleucine are likely to be 40, 17-25, and 19 mg . kg(-1) . d(-1), respectively. This adds up to a total of approximately 84 mg . kg(-1) . d(-1), which is much lower than the lowest estimate of the total BCAA requirement of approximately 110 mg . kg(-1) . d(-1) made by the short-term indicator amino acid oxidation (IAAO) method, which determined the BCAA requirement from the pattern of oxidation of an indicator amino acid (phenylyalanine) at different levels of BCAA intake. An additional estimate of the leucine requirement was also made by a meta-analysis of all available 24-h DAAO/DAAB data from different studies. This resulted in a higher value for the leucine requirement than that obtained by the specific studies that utilized the 24-h DAAO/DAAB approach; however, even adding this value to the total BCAA requirement does not account for the difference in the total BCAA requirement estimates and the summed individual BCAA estimates.
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Affiliation(s)
- Anura V Kurpad
- Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA.
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Kurpad AV, Regan MM, Raj TDS, Gnanou JV, Rao VN, Young VR. The daily valine requirement of healthy adult Indians determined by the 24-h indicator amino acid balance approach. Am J Clin Nutr 2005; 82:373-9. [PMID: 16087981 DOI: 10.1093/ajcn.82.2.373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND The 1985 FAO/WHO/UNU requirement for valine was set at 10 mg x kg(-1) x d(-1) on the basis of nitrogen balance studies carried out in Western subjects. It is likely that the requirement is higher, however, because the requirement of another branched-chain amino acid, leucine, was found to be about 3 times as high (40 mg x kg(-1) x d(-1)) as the 1985 FAO/WHO/UNU value (14 mg x kg(-1) x d(-1)). OBJECTIVE We assessed the valine requirement in healthy, well-nourished Indians by using 7 test valine intakes (5, 10, 15, 20, 25, 30, and 35 mg x kg(-1) x d(-1)) and the 24-h indicator amino acid oxidation (24-h IAAO) and balance (24-h IAAB) method, with phenylalanine as the indicator amino acid, while maintaining leucine intake at 40 mg x kg(-1) x d(-1). DESIGN Eighteen healthy, well-nourished Indian men were studied during each of 3 randomly assigned 7-d diet periods supplying valine intakes that were equally placed on either side of a putative mean valine requirement of 20 mg x kg(-1) x d(-1). Twenty-four-hour IAAO and 24-h IAAB were measured on day 7 by use of a 24-h [13C]phenylalanine tracer infusion. The breakpoint in the relation between these values and the valine intake was determined. RESULTS Two-phase linear regression of daily phenylalanine oxidation or balance against valine intake estimated a breakpoint in the response curve at a valine intake of 17 mg x kg(-1) x d(-1) (95% Fieller's CI: 11, > 35 and 11, 28 mg x kg(-1) x d(-1), respectively). CONCLUSION From the 24-h IAAO/IAAB approach, a mean valine requirement of 17 mg x kg(-1) x d(-1) is proposed for healthy, well-nourished Indian adults.
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Affiliation(s)
- Anura V Kurpad
- Division of Nutrition, Institute of Population Health and Clinical Research, St John's National Academy of Health Sciences, Bangalore, India.
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Kurpad AV, Regan MM, Raj TDS, Gnanou JV, Rao VN, Young VR. The daily valine requirement of healthy adult Indians determined by the 24-h indicator amino acid balance approach. Am J Clin Nutr 2005. [DOI: 10.1093/ajcn/82.2.373] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Anura V Kurpad
- From the Division of Nutrition (AVK, TDSR, and VNR) and the Core Biochemistry Laboratory (JVG), Institute of Population Health and Clinical Research, St John’s National Academy of Health Sciences, Bangalore, India, and the Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge, MA (MMR and VRY)
| | - Meredith M Regan
- From the Division of Nutrition (AVK, TDSR, and VNR) and the Core Biochemistry Laboratory (JVG), Institute of Population Health and Clinical Research, St John’s National Academy of Health Sciences, Bangalore, India, and the Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge, MA (MMR and VRY)
| | - Tony DS Raj
- From the Division of Nutrition (AVK, TDSR, and VNR) and the Core Biochemistry Laboratory (JVG), Institute of Population Health and Clinical Research, St John’s National Academy of Health Sciences, Bangalore, India, and the Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge, MA (MMR and VRY)
| | - Justin V Gnanou
- From the Division of Nutrition (AVK, TDSR, and VNR) and the Core Biochemistry Laboratory (JVG), Institute of Population Health and Clinical Research, St John’s National Academy of Health Sciences, Bangalore, India, and the Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge, MA (MMR and VRY)
| | - Vidya N Rao
- From the Division of Nutrition (AVK, TDSR, and VNR) and the Core Biochemistry Laboratory (JVG), Institute of Population Health and Clinical Research, St John’s National Academy of Health Sciences, Bangalore, India, and the Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge, MA (MMR and VRY)
| | - Vernon R Young
- From the Division of Nutrition (AVK, TDSR, and VNR) and the Core Biochemistry Laboratory (JVG), Institute of Population Health and Clinical Research, St John’s National Academy of Health Sciences, Bangalore, India, and the Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge, MA (MMR and VRY)
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Elango R, Goonewardene LA, Pencharz PB, Ball RO. Parenteral and enteral routes of feeding in neonatal piglets require different ratios of branched-chain amino acids. J Nutr 2004; 134:72-8. [PMID: 14704296 DOI: 10.1093/jn/134.1.72] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The requirements for total branched-chain amino acids (BCAA), isoleucine, leucine and valine, in neonatal piglets receiving parenteral and enteral nutrition was determined recently. The optimum ratio among BCAA during different routes of feeding is not yet known. In this study, the ratio of BCAA during parenteral and enteral feeding was tested using the indicator amino acid oxidation (IAAO) technique. Male Yorkshire piglets (n=24) received amino acid-based diets containing adequate nutrients for 5 d. Phenylalanine oxidation and kinetics were determined from a 4-h primed, constant infusion of L-[1-14C]-phenylalanine on d 6 and 8. On d 6, all piglets received a BCAA diet which met 75% of the total BCAA requirement, based on our previous research, with a ratio of 1:1.8:1.2 of isoleucine/leucine/valine. On d 8, the piglets were randomly assigned to receive one of the 3 test diets supplemented with isoleucine (+isoleucine), leucine (+leucine) or valine (+valine) to meet 100% of requirement, with the remaining two BCAA at 75% of requirement. The difference in phenylalanine oxidation (% of dose) between d 6 and 8 was used as an indicator of BCAA adequacy. In enterally fed piglets, the change in the percentage of the dose oxidized was minimal for all 3 test diets (mean=1.15%). In parenterally fed piglets, the difference in phenylalanine oxidation (% of dose) between d 6 and 8 was +isoleucine (12.6%), +leucine (2%) and +valine (6.6%). The ratio of 1:1.8:1.2 of isoleucine/leucine/valine is appropriate for enteral feeding, but during parenteral feeding, isoleucine was first limiting and valine was second limiting.
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Affiliation(s)
- Rajavel Elango
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5
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Riazi R, Rafii M, Wykes LJ, Ball RO, Pencharz PB. Valine May Be the First Limiting Branched-Chain Amino Acid in Egg Protein in Men. J Nutr 2003; 133:3533-9. [PMID: 14608070 DOI: 10.1093/jn/133.11.3533] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recently, we defined an estimate for total branched-chain amino acids (BCAA) using the indicator amino acid oxidation technique in men fed the three BCAA (leucine, isoleucine and valine) in the proportion present in egg protein. Although egg protein is regarded as a high quality dietary protein source, it is not known whether the proportions of the three BCAA are optimal. Five men with known total BCAA requirements were restudied. Each men was studied with isoleucine, leucine or valine held constant at that individual's requirement level while the intake of the other two BCAA was reduced; one BCAA was held constant and the intake of the other two was reduced by 10 and 20% in random order. The label appearance from the oxidation of L-[13C]-phenylalanine to 13CO2 (F13CO2) in breath was monitored in response to the change in amino acid intake. When either isoleucine or leucine was held constant, and the other two BCAA reduced by 20% (valine and leucine, or valine and isoleucine, respectively) F13CO2 increased (P = 0.007, P = 0.038, respectively). We conclude that valine may be the first limiting BCAA in egg protein.
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Affiliation(s)
- Roya Riazi
- Department of Nutritional Sciences, The University of Toronto, Toronto, Canada
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Mager DR, Wykes LJ, Ball RO, Pencharz PB. Branched-Chain Amino Acid Requirements in School-Aged Children Determined by Indicator Amino Acid Oxidation (IAAO). J Nutr 2003; 133:3540-5. [PMID: 14608071 DOI: 10.1093/jn/133.11.3540] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The current WHO/FAO/UNU recommendations for BCAA requirements in school-aged children are based on nitrogen balance studies that have tended to produce lower estimates of amino acid requirements that those determined using stable isotope methodologies. The new dietary reference intake (DRI) recommendations for total BCAA requirements in children were determined using a factorial approach that included adult BCAA requirements plus the additional needs for growth. The purpose of this study was to determine directly total BCAA requirements in school children aged 6-10 y using indicator amino acid oxidation (IAAO). Five children (8.5 +/- 1.2 y) were assigned randomly to receive 7 graded intakes of total BCAA. Individual BCAA in the test diet were provided in the same proportions as those present in egg protein to minimize the potential interactive effects of individual BCAA on assessment of requirement. Total BCAA requirement was determined by measuring the oxidation of L-[1-13C] phenylalanine to 13CO2 [F13CO2 in micromol/(kg x h)], after a primed, continuous infusion of the labeled tracer and using a two-phase linear crossover regression analysis. The mean requirement and the population-safe intake level (upper limit of the 95% CI) of the total BCAA in healthy school aged children were 147 and 192 mg/(kg x d), respectively. The estimated mean requirements of the total BCAA as determined by IAAO is approximately 48% higher than the current DRI recommendations, suggesting that these recommendations may be too low to meet the needs of school-aged children.
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Affiliation(s)
- Diana R Mager
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada
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Riazi R, Wykes LJ, Ball RO, Pencharz PB. The total branched-chain amino acid requirement in young healthy adult men determined by indicator amino acid oxidation by use of L-[1-13C]phenylalanine. J Nutr 2003; 133:1383-9. [PMID: 12730426 DOI: 10.1093/jn/133.5.1383] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Previous recommendations for branched-chain amino acids (BCAA), based on nitrogen balance studies, were found to be low in a series of stable isotope-labeled amino acid studies. The BCAA requirement was increased in the new dietary reference intake (DRI) report on the basis of a series of stable isotope studies examining the requirement of leucine and valine individually, but not isoleucine. To reduce the possibility of interactions among these amino acids and imbalances in the mixture affecting the estimate of requirements, we decided to determine the requirement for the total BCAA of young healthy adult men, receiving a mixture of BCAA based on the proportion of these amino acids in egg protein, by use of indicator amino acid oxidation. Seven men were assigned to receive nine graded intakes of a BCAA mixture in random order: 34, 50, 66, 80, 100, 120, 140, 160 and 180 mg/(kg. d). The rate of release of (13)CO(2) from the oxidation of L-[1-(13)C]phenylalanine (F (13)CO(2)) was measured and a two-phase linear regression crossover model was applied to determine total BCAA requirement. The mean requirement and population-safe level (upper limit of 95% confidence interval) of the total BCAA were 144 and 210 mg/(kg. d), respectively. Based on the balance of BCAA in egg protein, our estimate for the mean leucine requirement is 55 mg/(kg. d), which is substantially higher than the 34 mg/(kg. d) recommended by the DRI.
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Affiliation(s)
- Roya Riazi
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3E2
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Crenn P, Thuillier F, Rakotoambinina B, Rongier M, Darmaun D, Messing B. Duodenal vs. gastric administration of labeled leucine for the study of splanchnic metabolism in humans. J Appl Physiol (1985) 2000; 89:573-80. [PMID: 10926640 DOI: 10.1152/jappl.2000.89.2.573] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Low-rate (6 ml/h) intragastric infusion of stable, isotope-labeled amino acids is commonly used to assess the splanchnic handling of amino acids in humans. However, when used in the postabsorptive state, this method yields unreliable plasma isotopic enrichments, with a coefficient of variation >10%. In this metabolic condition, we confirmed in six subjects that an intragastric infusion of L-[(2)H(3)]leucine at 6 ml/h yields an unreliable isotopic steady state in plasma amino acids with a coefficient of variation of 43 +/- 12% (mean +/- SD). In five additional subjects, we assessed the effects of 1) increasing the rate of delivery of a leucine tracer in an isotonic plasmalike solution at 240 ml/h into the gastric site, and 2) changing the site of infusion from gastric to duodenal with this same high rate of delivery. In contrast to the gastric route, and regardless of the rate of delivery, only the intraduodenal route allowed 1) isotopic plasma steady state (i.e., coefficients of variation were <10%: 5 +/- 3%), and 2) reproducible leucine extraction coefficients (22 +/- 5%). We conclude that an infusion site that bypasses the gastric emptying process, i.e., the duodenal route, along with delivery of a plasmalike solution, is necessary to reach isotopic steady state in plasma when labeled leucine is infused into the gastrointestinal tract in the postabsorptive state.
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Affiliation(s)
- P Crenn
- Institut National de la Santé et de la Recherche Médicale, U 290, Hôpital Lariboisière-Saint-Lazare, Paris, France
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Millward DJ. Metabolic demands for amino acids and the human dietary requirement: Millward and rRvers (1988) revisited. J Nutr 1998; 128:2563S-2576S. [PMID: 9868206 DOI: 10.1093/jn/128.12.2563s] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In 1988, Millward and Rivers reappraised existing metabolic models for amino acid requirements. The metabolic demand for amino acids was reviewed in relation to both obligatory metabolic consumption and adaptive pathways of amino acid oxidation. The obligatory demand pattern was deemed unknowable from first principles except that the level of one amino acid would be similar to its concentration in an amount of tissue protein equivalent to the obligatory nitrogen loss. The adaptive demand pattern was predicted to vary in relation to the amount and the periodicity of food protein intake that influenced the amplitude of the diurnal cycle of gains and losses. A regulatory influence of protein intake on anabolism, the anabolic drive, was identified in animal studies; benefit appeared to derive from intakes in excess of the minimum for balance, which could facilitate definition of an optimal requirement. The inherent and design-related limitations of both nitrogen and stable isotope balance studies of requirement were recognized as a major problem in identifying secure values for indispensable amino acid requirements. A decade of research of increasing methodological sophistication has generated much new information, confirming the adaptive diurnal model of balance regulation and allowing development of the anabolic drive into a general protein-stat theory for coordinated control of growth and maintenance of the lean body mass. However, notwithstanding several new estimates of amino acid requirement values, definition of a widely accepted human amino acid requirement pattern remains unresolved. Although a case can be made for an adjusted 1985 FAO adult requirement pattern being a reasonable estimate of the obligatory indispensable amino acid requirements for human maintenance, the problems posed by adaptation, methodological inadequacies and lack of independent measures of adequacy mean that assessment of the adequacy of the human diet to satisfy amino acid needs remains inherently difficult.
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Affiliation(s)
- D J Millward
- Centre for Nutrition and Food Safety, School of Biological Sciences, University of Surrey, Guildford, Surrey GU2 5XH, UK
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