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Pezzali JG, Lambie JG, Phillips SM, Shoveller AK. Determination of a steady-state isotope dilution protocol for carbon oxidation studies in the domestic cat. J Nutr Sci 2023; 12:e62. [PMID: 37313346 PMCID: PMC10260335 DOI: 10.1017/jns.2023.44] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 06/15/2023] Open
Abstract
The present study aimed to develop an isotope protocol to achieve equilibrium of 13CO2 in breath of cats during carbon oxidation studies using L-[1-13C]-Phenylalanine (L-[1-13C]-Phe), provided orally in repeated meals. One adult male cat was used in two experiments. In each experiment, three isotope protocols were tested in triplicate using the same cat. During carbon oxidation study days, the cat was offered thirteen small meals to achieve and maintain a physiological fed state. In experiment 1, the isotope protocols tested (A, B and C) had a similar priming dose of NaH13CO3 (0⋅176 mg/kg; offered in meal 6), but different priming [4⋅8 mg/kg (A) or 9⋅4 mg/kg (B and C); provided in meal 6] and constant [1⋅04 mg/kg (A and B) or 2⋅4 mg/kg (C); offered in meals 6-13] doses of L-[1-13C]-Phe. In experiment 2, the isotope protocols tested (D, E and F) had similar priming (4⋅8 mg/kg; provided in meal 5) and constant (1⋅04 mg/kg; provided in meals 5-13) doses of L-[1-13C]-Phe, but increasing priming doses of NaH13CO3 (D: 0⋅264, E: 0⋅352, F: 0⋅44 mg/kg; provided in meal 4). Breath samples were collected using respiration chambers (25-min intervals) and CO2 trapping to determine 13CO2:12CO2. Isotopic steady state was defined as the enrichment of 13CO2, above background samples, remaining constant in at least the last three samples. Treatment F resulted in the earliest achievement of 13CO2 steady state in the cat's breath. This feeding and isotope protocol can be used in future studies aiming to study amino acid metabolism in cats.
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Affiliation(s)
- Julia Guazzelli Pezzali
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, Canada
- Department of Animal Science, Iowa State University, Ames, IA, United States
| | - Jocelyn G. Lambie
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, Canada
| | | | - Anna K. Shoveller
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, Canada
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2
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Ennis MA, Ong AJ, Lim K, Ball RO, Pencharz PB, Courtney-Martin G, Elango R. Dietary Aromatic Amino Acid Requirements During Early and Late Gestation in Healthy Pregnant Women. J Nutr 2020; 150:3224-3230. [PMID: 33188409 PMCID: PMC7726121 DOI: 10.1093/jn/nxaa317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/07/2020] [Accepted: 09/22/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Phenylalanine and tyrosine (referred to as total aromatic amino acids; TAAs) are essential for protein synthesis, and are precursors for important catecholamines. Current estimated average requirement (EAR) recommendations for TAA during pregnancy are 36 mg·kg-1·d-1, and has not been experimentally determined. OBJECTIVES The aim was to determine TAA requirements (dietary phenylalanine in the absence of tyrosine) during early and late gestation using the indicator amino acid oxidation (IAAO, with L-[1-13C]leucine) technique. METHODS Nineteen healthy pregnant women (age 22-38 y) were studied at a range of phenylalanine intakes (5 to 100 mg·kg-1·d-1) in early (13-19 wk) and/or late (33-39 wk) pregnancy for a total of 51 study days. Graded test intakes were provided as 8 hourly isonitrogenous and isocaloric meals. Breath samples were collected for 13C enrichment analysis on an isotope ratio mass spectrometer. A plasma sample was collected and analyzed for phenylalanine and tyrosine concentrations on an amino acid analyzer. The TAA requirement in early and late pregnancy was calculated using 2-phase linear regression crossover analysis that identified breakpoints in 13CO2 production (the requirement) in response to phenylalanine intakes. RESULTS TAA requirement during early pregnancy was 44 mg·kg-1·d-1 (95% CI: 28.3, 58.8) and during late pregnancy was 50 mg·kg-1·d-1 (95% CI: 36.1, 63.1). In early and late pregnancy, plasma phenylalanine and tyrosine concentrations rose linearly in response to graded phenylalanine intakes. CONCLUSIONS Our results suggest that the current EAR of 36 mg·kg-1·d-1 for TAAs is underestimated. When compared with results previously determined in nonpregnant adults, early pregnancy requirements were similar (43 compared with 44 mg·kg-1·d-1, respectively). During late pregnancy, a 14% higher TAA requirement was observed when compared with early pregnancy. The results from this study have potential implications for creating gestation stage-specific TAA recommendations.
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Affiliation(s)
- Madeleine A Ennis
- British Columbia Children's Hospital Research Institute, British Columbia Children's Hospital, Vancouver, Canada,Department of Pediatrics, University of British Columbia, Vancouver, Canada
| | - Anna-Joy Ong
- British Columbia Children's Hospital Research Institute, British Columbia Children's Hospital, Vancouver, Canada
| | - Kenneth Lim
- Department of Obstetrics and Gynecology, British Columbia Women's Hospital, Vancouver, Canada
| | - Ronald O Ball
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, Canada
| | - Paul B Pencharz
- Research Institute, The Hospital for Sick Children, Toronto, Canada,Department of Nutritional Sciences, University of Toronto, Toronto, Canada,Department of Pediatrics, University of Toronto, Toronto, Canada
| | - Glenda Courtney-Martin
- Research Institute, The Hospital for Sick Children, Toronto, Canada,Department of Nutritional Sciences, University of Toronto, Toronto, Canada
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3
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Elango R. Methionine Nutrition and Metabolism: Insights from Animal Studies to Inform Human Nutrition. J Nutr 2020; 150:2518S-2523S. [PMID: 33000159 DOI: 10.1093/jn/nxaa155] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 04/16/2020] [Accepted: 05/08/2020] [Indexed: 12/18/2022] Open
Abstract
Methionine is a nutritionally indispensable amino acid, and is unique among indispensable amino acids due to its sulfur atom. Methionine is involved in cysteine synthesis via the transsulfuration pathway, which is rate limiting for the key antioxidant molecule, glutathione. Methionine is also the primary methyl donor in the body through S-adenosylmethionine via the transmethylation pathway, which is involved in the synthesis of several key metabolites including creatine and phosphatidylcholine. Methionine can also be remethylated from homocysteine, in the presence of betaine via choline and/or folate. Thus methionine demands from a dietary perspective are regulated not only by the presence of cysteine in the body, but also by the demands in vivo for the various metabolites formed from it, and also by the presence of these compounds in foods. Indeed, methionine, cysteine, and the various methyl donors/acceptors vary in human foods, and thus regulate methionine availability, especially under conditions of growth and development. Much of our understanding of methionine nutrition and metabolism arises from experiments in animal models. This is because most animal feed formulations are plant-based and plant sources are relatively low in methionine and cysteine amounts. Thus, this brief review will touch on some broad aspects of human methionine nutrition, including requirements in different life stages, disease, and bioavailability, with some examples from the insights/lessons learned from experiments initially conducted in animals.
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Affiliation(s)
- Rajavel Elango
- BC Children's Hospital Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada; and the Department of Pediatrics, and School of Population and Public Health, University of British Columbia, British Columbia, Canada
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Zhang J, Cui YQ, Luo Y, Chen XX, Li J. Assessment of Energy and Protein Requirements in Relation to Nitrogen Kinetics, Nutrition, and Clinical Outcomes in Infants Receiving Early Enteral Nutrition Following Cardiopulmonary Bypass. JPEN J Parenter Enteral Nutr 2020; 45:553-566. [PMID: 32495992 DOI: 10.1002/jpen.1863] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 04/29/2020] [Indexed: 11/09/2022]
Abstract
BACKGROUND Nutrition therapies in children with congenital heart disease (CHD) after cardiopulmonary bypass (CPB) is crucial, but energy and protein requirements remain undefined. We assessed energy and protein requirements, with nitrogen kinetics and clinical outcomes, in infants with complex CHD following CPB. METHODS Infants were randomized to control (1.3 g/kg/d), moderate protein (MP, 2.5 g/kg/d), or high protein (HP, 4 g/kg/d) groups. Resting energy expenditure (REE) was measured 6 hours post-CPB and then at 24-hour intervals, using indirect calorimetry to formulate energy intakes. Enteral formula feeding was initiated 6 hours post-CPB and continued for 5 days. Nitrogen balance (NB); urea nitrogen waste and nitrogen retention; serum prealbumin level; and hepatic, renal, and cardiac function were measured daily. Mid-upper arm circumference and triceps skinfold were measured preoperatively and 5 days after CPB. Adverse outcomes (bacterial infection, reintubation, and cardiac intensive care unit (CICU) stay > 8 days) were recorded. RESULTS REE was not different across the 3 groups (P = .37). It declined from 62 ± 6 to 57 ± 7 kcal/kg/d over 5 days post-CPB (P = .02). NB and nitrogen retention became positive by day 3 in the HP group but remained negative in the other 2 groups (P = .045-.003), despite higher urea nitrogen waste in the HP group (P < .0001). The HP group had a greater increase in serum prealbumin level and anthropometric measures (P = .009-.03). Other measures were not significantly different across the 3 groups. CONCLUSIONS In infants with complex CHD in the first 5 days post-CPB, protein and energy intakes of ≈4 g/kg/d and 60 kcal/kg/d, respectively, led to improved nutrition outcomes without increased adverse events.
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Affiliation(s)
- Jian Zhang
- Clinical Physiology Laboratory, Capital Institute of Pediatrics, Graduate School of Peking Union Medical College, Beijing, China
| | - Yan-Qin Cui
- Cardiac Intensive Care Unit, Heart Center, Guangzhou Women and Children's, Guangzhou Medical University, Guangzhou, Guangdong Province, China.,Department of Pediatric Surgery, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong Province, China
| | - Yi Luo
- Department of Cardiac Surgery, Children's Hospital affiliated to Capital Institute of Pediatrics, Beijing, China
| | - Xin-Xin Chen
- Department of Pediatric Surgery, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong Province, China.,Department of Cardiac Surgery, Heart Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong Province, China
| | - Jia Li
- Clinical Physiology Laboratory, Capital Institute of Pediatrics, Graduate School of Peking Union Medical College, Beijing, China.,Department of Pediatric Surgery, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong Province, China.,Department of Cardiac Surgery, Heart Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong Province, China.,Clinical Physiology Laboratory, Institute of Pediatrics, Heart Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong Province, China
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Al-Mokbel A, Courtney-Martin G, Elango R, Ball RO, Pencharz PB, Tomlinson C. Tryptophan Requirement in School-Age Children Determined by the Indicator Amino Acid Oxidation Method is Similar to Current Recommendations. J Nutr 2019; 149:280-285. [PMID: 30753549 DOI: 10.1093/jn/nxy250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/09/2018] [Accepted: 09/04/2018] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The requirement for dietary tryptophan in school-age children has never been empirically derived. OBJECTIVE The objective of our study was to determine the tryptophan requirement of school-age children using the indicator amino acid oxidation technique. METHODS Volunteer healthy school-age children, between 8 and 12 y, were enrolled and the oxidation of l-[13C]-phenylalanine to 13CO2 measured in response to graded intakes of dietary tryptophan. Seven children (3 boys, 4 girls) participated in the study and received randomly assigned tryptophan intakes ranging from 0.5 to 9.75 mg.kg-1.d-1 for a total of 36 studies. The diets provided energy at 1.5 times each subject's resting energy expenditure and were isocaloric. Protein was provided as an amino acid mixture on the basis of the egg protein pattern, and phenylalanine and tyrosine were maintained constant across the protein intake concentrations at 25 and 40 mg.kg-1.d-1. All subjects were adapted for 2 d before the study day to a protein intake of 1.5 g.kg-1.d-1. The mean tryptophan requirement was determined by applying a mixed-effect change-point regression analysis to F13CO2 (label tracer oxidation in 13CO2 breath) which identified a breakpoint in the F13CO2 in response to graded amounts of tryptophan. RESULTS The mean [estimated average requirement (EAR)] and upper 95% CI, (approximating the RDA) of tryptophan requirements were estimated to be 4.7 and 6.1 mg.kg-1.d-1, respectively. CONCLUSION Our results are similar to the current recommended EAR and RDA of 5 and 6 mg.kg-1.d-1 for healthy growing children based on the factorial calculation. Clinical Trials Registration No. NCT02018588.
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Affiliation(s)
- Abeer Al-Mokbel
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Faculty of Kinesiology & Physical Education.,Departments of Nutritional Sciences
| | - Rajavel Elango
- Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada.,Child & Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Ronald O Ball
- Departments of Nutritional Sciences.,Department of Agriculture, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Paul B Pencharz
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Departments of Nutritional Sciences.,Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Christopher Tomlinson
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Departments of Nutritional Sciences
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ESPGHAN/ESPEN/ESPR/CSPEN guidelines on pediatric parenteral nutrition: Amino acids. Clin Nutr 2018; 37:2315-2323. [DOI: 10.1016/j.clnu.2018.06.945] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 05/29/2018] [Indexed: 02/02/2023]
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Payne M, Stephens T, Lim K, Ball RO, Pencharz PB, Elango R. Lysine Requirements of Healthy Pregnant Women are Higher During Late Stages of Gestation Compared to Early Gestation. J Nutr 2018; 148:94-99. [PMID: 29378056 DOI: 10.1093/jn/nxx034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 11/07/2017] [Indexed: 11/13/2022] Open
Abstract
Background Lysine is the first limiting amino acid in cereal proteins and is found mainly in animal-derived products. Current Dietary Reference Intake (DRI) recommendations extrapolate lysine requirements during pregnancy from nonpregnant adult data, and may underestimate true requirements. Objective Our objective is to define a quantitative lysine requirement in healthy pregnant women and to determine whether requirements vary between 2 phases of gestation. Methods Fourteen pregnant women in early (12-19 wk) and 19 women in late (33-39 wk) gestation were studied using the indicator amino acid oxidation technique. Individual lysine intakes (6-84 mg · kg-1 · d-1, deficient to excess) were tested on each study day as a crystalline amino acid mixture based on egg protein composition. Isonitrogenous diets maintained protein intake at 1.5 g · kg-1 · d-1 and calorie intake at 1.7 times resting energy expenditure during each study day. Phenylalanine and tyrosine intakes were held constant across all lysine intakes. Breath and urine samples were collected at baseline and isotopic steady state. Lysine requirements were determined by measuring the oxidation of L-[1-13C]-phenylalanine to 13CO2 (F13CO2). Biphase linear regression crossover analysis was used to determine a breakpoint (which represents the estimated average requirement, EAR) in F13CO2. Results The EAR for lysine during early gestation was determined to be 36.6 mg · kg-1 · d-1 (R2 = 0.484, upper 95% CI = 46.2 mg · kg-1 · d-1), similar to an earlier adult requirement of 36 mg · kg-1 · d-1. The EAR for lysine during late gestation was determined to be 50.3 mg · kg-1 · d-1 (R2 = 0.664, upper 95% CI = 60.4 mg · kg-1 · d-1), 23% higher than the current pregnancy DRI EAR recommendation of 41 mg · kg-1 · d-1. Conclusions Our results suggest that lysine requirements are higher during late gestation compared to early gestation, and that current dietary lysine recommendations during late stages of pregnancy may be underestimated. The results have implications for populations consuming cereal-based diets as their primary source of protein. This trial was registered at clinicaltrials.gov as NCT01776931.
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Affiliation(s)
- Magdalene Payne
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Pediatrics, Obstetrics and Gynecology, and School of Population and Public Health, University of British Columbia, British Columbia, Canada
| | - Trina Stephens
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Pediatrics, Obstetrics and Gynecology, and School of Population and Public Health, University of British Columbia, British Columbia, Canada
| | - Kenneth Lim
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Obstetrics and Gynecology, and School of Population and Public Health, University of British Columbia, British Columbia, Canada
| | - Ronald O Ball
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Paul B Pencharz
- The Research Institute, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada
| | - Rajavel Elango
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Pediatrics, Obstetrics and Gynecology, and School of Population and Public Health, University of British Columbia, British Columbia, Canada.,School of Population and Public Health, University of British Columbia, British Columbia, Canada
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8
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Munasinghe LL, Robinson JL, Harding SV, Brunton JA, Bertolo RF. Protein Synthesis in Mucin-Producing Tissues Is Conserved When Dietary Threonine Is Limiting in Piglets. J Nutr 2017; 147:202-210. [PMID: 28053172 DOI: 10.3945/jn.116.236786] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/17/2016] [Accepted: 12/01/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The neonatal gastrointestinal tract extracts the majority of dietary threonine on the first pass to maintain synthesis of threonine-rich mucins in mucus. As dietary threonine becomes limiting, this extraction must limit protein synthesis in extraintestinal tissues at the expense of maintaining protein synthesis in mucin-producing tissues. OBJECTIVE The objective was to determine the dietary threonine concentration at which protein synthesis is reduced in various tissues. METHODS Twenty Yucatan miniature piglets (10 females; mean ± SD age, 15 ± 1 d; mean ± SD weight, 3.14 ± 0.30 kg) were fed 20 test diets with different threonine concentrations, from 0.5 to 6.0 g/100 g total amino acids (AAs; i.e., 20-220% of requirement), and various tissues were analyzed for protein synthesis by administering a flooding dose of [3H]phenylalanine. The whole-body requirement was determined by [1-14C]phenylalanine oxidation and plasma threonine concentrations. RESULTS Breakpoint analysis indicated a whole-body requirement of 2.8-3.0 g threonine/100 g total AAs. For all of the non-mucin-producing tissues as well as lung and colon, breakpoint analyses indicated decreasing protein synthesis rates below the following concentrations (expressed in g threonine/100 g total AAs; mean ± SE): gastrocnemius muscle, 1.76 ± 0.23; longissimus dorsi muscle, 2.99 ± 0.50; liver, 2.45 ± 0.60; kidney, 3.81 ± 0.97; lung, 1.95 ± 0.14; and colon, 1.36 ± 0.29. Protein synthesis in the other mucin-producing tissues (i.e., stomach, proximal jejunum, midjejunum, and ileum) did not change with decreasing threonine concentrations, but mucin synthesis in the ileum and colon decreased over threonine concentrations <4.54 ± 1.50 and <3.20 ± 4.70 g/100 g total AAs, respectively. CONCLUSIONS The results of this study illustrate that dietary threonine is preferentially used for protein synthesis in gastrointestinal tissues in piglets. If dietary threonine intake is deficient, then muscle growth and the functions of other tissues are likely compromised at the expense of maintenance of the mucus layer in mucin-producing tissues.
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Affiliation(s)
- Lalani L Munasinghe
- Department of Biochemistry, Memorial University of Newfoundland, Newfoundland and Labrador, St. John's, Canada; and
| | - Jason L Robinson
- Department of Biochemistry, Memorial University of Newfoundland, Newfoundland and Labrador, St. John's, Canada; and
| | - Scott V Harding
- King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, London, United Kingdom
| | - Janet A Brunton
- Department of Biochemistry, Memorial University of Newfoundland, Newfoundland and Labrador, St. John's, Canada; and
| | - Robert F Bertolo
- Department of Biochemistry, Memorial University of Newfoundland, Newfoundland and Labrador, St. John's, Canada; and
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Abstract
OBJECTIVE Threonine is one of the essential amino acids. Its major fate is incorporation into intestinal mucosal proteins and synthesis of secretory glycoproteins. Therefore, it has an important function in the neonatal gut barrier integrity. The objective was to quantify the threonine requirement in fully enterally fed term neonates by means of the indicator amino acid oxidation (IAAO) method, using L-[1-C]phenylalanine as indicator. METHODS After a 24-hour test diet adaptation, containing randomly assigned amounts of threonine (range 5-182 mg · kg · day), the participating neonates received a primed continuous infusion of [C]bicarbonate and L-[1-C]phenylalanine. At baseline and during the plateau phase of both infusions, breath samples were obtained for CO2. The fractional L-[1-C]phenylalanine oxidation (FCO2) was estimated and plotted against the threonine intakes. Biphasic linear regression crossover analysis was used to calculate the breakpoint of the FCO2, representing the mean threonine requirement. Data are presented as mean ± SD. RESULTS Thirty-two term neonates (gestational age 39 ± 1 weeks, birth weight 3.3 ± 0.3 kg, mean postnatal age 10 ± 4 days) were studied. The mean threonine requirement was estimated to be 68 mg · kg · day with an upper and lower 95% confidence interval of 104 and 32 mg · kg · day, respectively (r = 0.37). CONCLUSIONS The determined threonine requirement is extremely close to the existing requirement recommendations (∼90% of the present World Health Organization requirement guidelines). Infant formula preparations presently on the market, however, contain up to twice as much threonine as recommended. The threonine intake in formula-fed infants may therefore be reduced considerably.
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Hogewind-Schoonenboom JE, Zhu L, Zhu L, Ackermans EC, Mulders R, Te Boekhorst B, Wijnen M, Bijnevelt L, Voortman GJ, Schierbeek H, Huang L, de Groof F, Vermes A, Chen C, Huang Y, van Goudoever JB. Phenylalanine requirements of enterally fed term and preterm neonates. Am J Clin Nutr 2015; 101:1155-62. [PMID: 25926506 DOI: 10.3945/ajcn.114.089664] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 03/17/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Phenylalanine, which is an essential aromatic amino acid, is either used for protein synthesis or irreversibly hydroxylated to tyrosine. The provision of optimal amounts of dietary phenylalanine is not only important for growth and development but might also influence catecholamine synthesis and release rates. The current recommended aromatic amino acid requirement for infants aged 0-6 mo is based on the amino acid content of human milk. OBJECTIVE We quantified the requirements for phenylalanine in the presence of excess tyrosine (166 or 177 mg/kg per day for term and preterm infants, respectively) for term and preterm neonates by using the indicator amino acid oxidation method with l-[1-(13)C]lysine 2HCl as an indicator. Hence, we determined the minimum obligatory phenylalanine requirement. DESIGN Fully enterally fed term and preterm infants received randomly graded amounts of phenylalanine (5-177 mg/kg per day) as part of an elemental formula. Data are expressed as means ± SDs. RESULTS Twenty term (birth weight: 3.19 ± 0.34 kg; gestational age: 38.9 ± 1 wk) and 16 preterm (birth weight: 1.75 ± 0.17 kg; gestational age: 32.5 ± 0.6 wk) Asian infants participated at a postnatal age of 17 ± 8 d. In total, 44 studies were performed. The minimum obligatory phenylalanine requirement was 58 mg/kg per day (95% CI: 38-78 mg/kg per day) and 80 mg/kg per day (95% CI: 40-119 mg/kg per day) for term and preterm infants, respectively. CONCLUSION The determined mean phenylalanine-requirement estimates are lower than the contents of term and preterm formulas currently on the market. This trial was registered at www.trialregister.nl as NTR1610.
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Affiliation(s)
- Jacomine E Hogewind-Schoonenboom
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Li Zhu
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Lin Zhu
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Eveline Cam Ackermans
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Renske Mulders
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Bart Te Boekhorst
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Mandy Wijnen
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Lianne Bijnevelt
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Gardi J Voortman
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Henk Schierbeek
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Lisha Huang
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Femke de Groof
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Andras Vermes
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Chao Chen
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Ying Huang
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG)
| | - Johannes B van Goudoever
- From the Department of Pediatrics, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands (JEH-S, HS, Li Zhu, and JBvG); the Department of Pediatrics, Children's Hospital of Fudan University, Shanghai, China (Li Zhu, CC, and YH), Department of Pediatrics, Sophia Children's Hospital (JEH-S, Lin Zhu, MW, GJV, LH, FdG, and JBvG), and the Hospital Pharmacy (AV), Erasmus Medical Centre, Rotterdam, The Netherlands; The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (ECAMA, RM, BtB, and LB); and the Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands (JBvG).
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Rafii M, Chapman K, Owens J, Elango R, Campbell WW, Ball RO, Pencharz PB, Courtney-Martin G. Dietary protein requirement of female adults >65 years determined by the indicator amino acid oxidation technique is higher than current recommendations. J Nutr 2015; 145:18-24. [PMID: 25320185 DOI: 10.3945/jn.114.197517] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Studies on protein requirements in vulnerable groups such as older adults are few, and results are conflicting. OBJECTIVE The main objective of this study was to determine the protein requirements of free-living women >65 y by measuring the oxidation of l-[1-(13)C]phenylalanine to (13)CO2 in response to graded intakes of protein. METHODS Twelve subjects participated in the study, with protein intakes ranging from 0.2 to 2.0 g · kg(-1) · d(-1) for a total of 82 studies. The diets provided energy at 1.5 times each subject's resting energy expenditure and were isocaloric. Protein was given as an amino acid mixture on the basis of the egg protein pattern, except for phenylalanine and tyrosine, which were maintained constant across the protein intake amounts. All subjects were adapted for 2 d before the study day to a protein intake of 1.0 g · kg(-1) · d(-1). The mean protein requirement was determined by applying a mixed-effects change-point regression analysis to F(13)CO2 (label tracer oxidation in (13)CO2 breath), which identified a breakpoint in the F(13)CO2 in response to graded amounts of protein. RESULTS The mean estimated average requirement (EAR) and upper 95% CI (approximating the RDA) protein requirement of women >65 y were 0.96 and 1.29 g · kg(-1) · d(-1), respectively. CONCLUSION These estimates of protein requirements for older women are higher than the current EAR and RDA based on nitrogen balance data, which are 0.66 and 0.80 g · kg(-1) · d(-1), respectively. This trial was registered at clinicaltrials.gov as NCT01604980.
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Affiliation(s)
- Mahroukh Rafii
- Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Karen Chapman
- Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Jillian Owens
- Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Rajavel Elango
- Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, Canada Child & Family Research Institute, BC Children's Hospital, Vancouver, Canada
| | - Wayne W Campbell
- Department of Nutrition Science, Purdue University, West Lafayette, IN
| | - Ronald O Ball
- Departments of Nutritional Sciences and Department of Agriculture, Food, and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Paul B Pencharz
- Research Institute, Hospital for Sick Children, Toronto, Canada Departments of Nutritional Sciences and Pediatrics, University of Toronto, Toronto, Canada; and Department of Agriculture, Food, and Nutritional Science, University of Alberta, Edmonton, Canada
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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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van Goudoever JB, Vlaardingerbroek H. The present challenges of parenteral nutrition in preterm infants and children. J Nutr 2013; 143:2059S-2060S. [PMID: 24108137 DOI: 10.3945/jn.113.176966] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The goal of pediatricians involved in the nutritional management of preterm infants is to mimic intrauterine growth and to obtain a functional outcome comparable to that for infants born at term. Appropriate administration of nutrients in the first few days to weeks of life will reduce the growth restriction that is frequently observed. Existing guidelines advise providing preterm infants with both amino acids and lipids from birth onward. Despite this knowledge, many hospital units do not comply with these guidelines. Further improvement of the quality of the composition of parenteral solutions for both neonates as well as older children should be the subject of further research.
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Affiliation(s)
- Johannes B van Goudoever
- Department of Pediatrics, Academic Medical Center-Emma Children's Hospital, Amsterdam, The Netherlands 5Department of Pediatrics, VU University Medical Centre, Amsterdam, The Netherlands
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Huang L, Hogewind-Schoonenboom JE, van Dongen MJA, de Groof F, Voortman GJ, Schierbeek H, Twisk JWR, Vermes A, Chen C, Huang Y, van Goudoever JB. Methionine requirement of the enterally fed term infant in the first month of life in the presence of cysteine. Am J Clin Nutr 2012; 95:1048-54. [PMID: 22492372 DOI: 10.3945/ajcn.111.028779] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The essential amino acid methionine can be used for protein synthesis but also serves as a precursor for homocysteine and cysteine. OBJECTIVE The objective of this study was to determine the minimal obligatory methionine requirement of infants in the presence of excess cysteine (91 mg ⋅ kg(-1) ⋅ d(-1)) by using the indicator amino acid oxidation (IAAO) method with l-[1-(13)C]phenylalanine as the indicator. DESIGN Fully enterally fed term infants <1 mo of age were randomly assigned to methionine intakes that ranged from 3 to 59 mg ⋅ kg(-1) ⋅ d(-1) as part of an elemental formula. After 1 d of adaptation to the test diet, [(13)C]bicarbonate and l-[1-(13)C]phenylalanine tracers were given enterally. Breath samples were collected at baseline and during isotopic plateaus. The mean methionine requirement was determined by using biphasic linear regression crossover analysis on the fraction of (13)CO(2) recovery from l-[1-(13)C]phenylalanine oxidation (F(13)CO(2)). Data are presented as means ± SDs. RESULTS Thirty-three neonates (gestational age: 39 ± 1 wk) were studied at 13 ± 6 d. With increasing methionine intakes, F(13)CO(2) decreased until a methionine intake of 38 mg ⋅ kg(-1) ⋅ d(-1); additional increases in methionine intake did not affect F(13)CO(2). The mean methionine requirement was determined at 38 mg ⋅ kg(-1) ⋅ d(-1), and the upper and lower CIs were 48 and 27 mg ⋅ kg(-1) ⋅ d(-11), respectively (P < 0.0001, r(2) = 0.59). CONCLUSIONS Although the current recommended methionine intake of 28 mg ⋅ kg(-1) ⋅ d(-1) is within the CIs of our study, the estimated mean requirement is substantially higher. However, most of the infant formulas provide a methionine intake of 49-80 mg ⋅ kg(-1) ⋅ d(-1), which is above the upper CI of our study. This trial was registered at www.trialregister.nl as NTR1610.
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Affiliation(s)
- Lisha Huang
- Department of Pediatrics, Division of Neonatology, Medical Centre-Sophia Children's Hospital, Rotterdam, Netherlands
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Huang L, Hogewind-Schoonenboom JE, de Groof F, Twisk JWR, Voortman GJ, Dorst K, Schierbeek H, Boehm G, Huang Y, Chen C, van Goudoever JB. Lysine requirement of the enterally fed term infant in the first month of life. Am J Clin Nutr 2011; 94:1496-503. [PMID: 22049162 DOI: 10.3945/ajcn.111.024166] [Citation(s) in RCA: 24] [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 Infant nutrition has a major impact on child growth and functional development. Low and high intakes of protein or amino acids could have a detrimental effect. OBJECTIVE The objective of the study was to determine the lysine requirement of enterally fed term neonates by using the indicator amino acid oxidation (IAAO) method. L-[1-(13)C]phenylalanine was used as an indicator amino acid. DESIGN Twenty-one neonates were randomly assigned to lysine intakes that ranged from 15 to 240 mg · kg(-1) · d(-1). Breath, urine, and blood samples were collected at baseline and during the plateau. The mean lysine requirement was determined by using biphasic linear regression crossover analysis on the fraction of (13)CO(2) recovery from L-[1-(13)C]phenylalanine oxidation (F(13)CO(2)) and phenylalanine oxidation rates calculated from the L-[1-(13)C]phenylalanine enrichment of urine and plasma. RESULTS The mean (±SD) phenylalanine flux calculated from urine and plasma L-[1-(13)C]phenylalanine enrichment data were 88.3 ± 6.9 and 84.5 ± 7.4 μmol · kg(-1) · h(-1), respectively. Graded intakes of lysine had no effect on phenylalanine fluxes. The mean lysine requirement determined by F(13)CO(2) was 130 mg · kg(-1) · d(-1) (upper and lower CIs: 183.7 and 76.3 mg · kg(-1) · d(-1), respectively). The mean requirement was identical to the requirement determined by using phenylalanine oxidation rates in urine and plasma. CONCLUSIONS The mean lysine requirement of enterally fed term neonates was determined by using F(13)CO(2) and phenylalanine oxidation rates calculated from the L-[1-(13)C]phenylalanine enrichment of urine and plasma. These methods yielded a similar result of 130 mg lysine · kg(-1) · d(-1). This study demonstrates that sampling of (13)CO(2) in expired air is sufficient to estimate the lysine requirement by using the IAAO method in infants. This trial was registered at www.trialregister.nl as NTR1610.
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Affiliation(s)
- Lisha Huang
- Department of Pediatrics, Division of Neonatology, Erasmus Medical Centre-Sophia Children's Hospital, Rotterdam, Netherlands
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Elango R, Humayun MA, Ball RO, Pencharz PB. Protein requirement of healthy school-age children determined by the indicator amino acid oxidation method. Am J Clin Nutr 2011; 94:1545-52. [PMID: 22049165 DOI: 10.3945/ajcn.111.012815] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The current Dietary Reference Intake (DRI) recommendations for protein requirements in children are based on a factorial estimate and have not been directly determined. OBJECTIVE The objective of the current study was to determine the protein requirement in healthy, school-age children by measuring the oxidation of L-[1-(13)C]-phenylalanine to (13)CO(2) [label tracer oxidation (F(13)CO(2))] in response to graded intakes of protein. DESIGN Seven healthy children (6-11 y old) each randomly received a minimum of 7 protein intakes (range: 0.1-2.56 g · kg(-1) · d(-1)) for a total of 56 studies. The diets provided energy at 1.7 times the resting energy expenditure and were made isocaloric by using carbohydrate. Protein was given as an amino acid mixture on the basis of the egg-protein pattern, except for phenylalanine and tyrosine intakes, which were maintained constant across intakes. The mean protein requirement was determined by applying a 2-phase linear regression crossover analysis on F(13)CO(2) data, which identified a breakpoint (requirement) at minimal F(13)CO(2) in response to graded amounts of protein intake. RESULTS Mean and population-safe (upper 95% CI) protein requirements were determined to be 1.3 and 1.55 g · kg(-1) · d(-1), respectively. These results are significantly higher than the mean and population-safe protein requirements currently recommended by the DRI 2005 for macronutrients (0.76 and 0.95 g · kg(-1) · d(-1), respectively). CONCLUSION To our knowledge, this study was the first to directly estimate protein requirements in children by using stable isotopes and indicated that current recommendations are severely underestimated.
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Affiliation(s)
- Rajavel Elango
- Research Institute, The Hospital for Sick Children, Toronto, Canada
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Abstract
PURPOSE OF REVIEW There are now different stable isotopic methods to measure minimum daily human indispensable amino acid (IAA) requirements. There has been debate on the appropriateness of statistical methods used to define the nature of change in the response. RECENT FINDINGS Current isotopic methods measure daily amino acid oxidation and balance of the IAA under test, or of a selected indicator amino acid, to graded intakes of the test IAA. A key concern is how response curves of oxidation/balance are analyzed to find the inflection point (breakpoint) at which the intake requirement is identified. Evaluating the pattern of the response to identify a breakpoint by a two-phase regression appears best. The indicator amino acid oxidation method has also been shortened and developed into a noninvasive protocol suitable for different populations and age groups. SUMMARY The indicator amino acid oxidation and balance method might be considered the best approach currently available, but it is challenging. The short-term indicator oxidation method is noninvasive and nondemanding. IAA requirements, based on these methods, have implications for the quality of protein in the dietary intake of populations. Methods that assess the IAA requirements to support optimal body function also need to be developed.
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Affiliation(s)
- Anura V Kurpad
- St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India.
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Yarandi SS, Zhao VM, Hebbar G, Ziegler TR. Amino acid composition in parenteral nutrition: what is the evidence? Curr Opin Clin Nutr Metab Care 2011; 14:75-82. [PMID: 21076291 PMCID: PMC3071792 DOI: 10.1097/mco.0b013e328341235a] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW Complete parenteral nutrition solutions contain mixed amino acid products providing all nine essential amino acids and a varying composition of nonessential amino acids. Relatively little rigorous comparative efficacy research on altered parenteral nutrition amino acid composition has been published in recent years. RECENT FINDINGS Limited data from randomized, double-blind, adequately powered clinical trials to define optimal doses of total or individual amino acids in parenteral nutrition are available. An exception is the growing number of studies on the efficacy of glutamine supplementation of parenteral nutrition or given as a single parenteral agent. Parenteral glutamine appears to confer benefit in selected patients; however, additional data to define optimal glutamine dosing and the patient subgroups who may most benefit from this amino acid are needed. Although some promising studies have been published, little data are available in the current era of nutrition support on the clinical efficacy of altered doses of arginine, branched chain amino acids, cysteine, or taurine supplementation of parenteral nutrition. SUMMARY Despite routine use of parenteral nutrition, surprisingly little clinical efficacy data are available to guide total or specific amino acid dosing in adult and pediatric patients requiring this therapy. This warrants increased attention by the research community and funding agencies to better define optimal amino acid administration strategies in patient subgroups requiring parenteral nutrition.
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Affiliation(s)
- Shadi S. Yarandi
- Department of Medicine, Emory University School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Vivian M. Zhao
- Nutrition and Metabolic Support Service, Emory University Hospital, Emory University, Atlanta, Georgia, USA
| | - Gautam Hebbar
- Department of Medicine, Emory University School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Thomas R. Ziegler
- Department of Medicine, Emory University School of Medicine, Emory University, Atlanta, Georgia, USA
- Nutrition and Metabolic Support Service, Emory University Hospital, Emory University, Atlanta, Georgia, USA
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Pencharz PB. Protein and energy requirements for ‘optimal’ catch-up growth. Eur J Clin Nutr 2010; 64 Suppl 1:S5-7. [DOI: 10.1038/ejcn.2010.39] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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van den Akker CHP, Vlaardingerbroek H, van Goudoever JB. Nutritional support for extremely low-birth weight infants: abandoning catabolism in the neonatal intensive care unit. Curr Opin Clin Nutr Metab Care 2010; 13:327-35. [PMID: 20216411 DOI: 10.1097/mco.0b013e328337d925] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Obviously, the ultimate goal in neonatology is to achieve a functional outcome in premature infants that is comparable to healthy term-born infants. As nutrition is one of the key factors for normal cell growth, providing the right amount and quality of nutrients could prove pivotal for normal development. However, many premature infants are catabolic during the first week of life, which has directly been linked to growth failure, disease, and suboptimal long-term outcome. This review describes the progress in research on parenteral nutrition for premature infants with a focus on amino acids and the influence of nutrition on later outcome. RECENT FINDINGS Although randomized clinical trials on early nutrition for premature infants remain relatively sparse, evidence is accumulating on its beneficial effects both on the short-term and long-term. However, some research also warns for adverse effects. SUMMARY Despite the fact that substantially improved nutritional therapies for preterm neonates have been implemented, still, some reluctance exists when it comes to providing high amounts of nutrition to the most immature infants. Pros and cons are outlined, as well as deficits in knowledge, when it comes to providing the optimal nutrient strategy in the first postnatal phase.
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Affiliation(s)
- Chris H P van den Akker
- Division of Neonatology, Department of Pediatrics, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
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Chapman KP, Courtney-Martin G, Moore AM, Langer JC, Tomlinson C, Ball RO, Pencharz PB. Lysine requirement in parenterally fed postsurgical human neonates. Am J Clin Nutr 2010; 91:958-65. [PMID: 20164307 DOI: 10.3945/ajcn.2009.28729] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The lysine requirement of human neonates receiving parenteral nutrition (PN) has not been determined experimentally. OBJECTIVE The objective was to determine the parenteral lysine requirement for human neonates by using the minimally invasive indicator amino acid oxidation technique with l-[1-(13)C] phenylalanine as the indicator amino acid. DESIGN Eleven postsurgical neonates were randomly assigned to 15 lysine intakes ranging from 50 to 260 mg . kg(-1) . d(-1). Breath and urine samples were collected at baseline and at plateau for (13)CO(2) (F(13)CO(2)) and amino acid enrichment, respectively. The mean lysine requirement was determined by applying a 2-phase linear regression crossover analysis to the measured rates of F(13)CO(2) release and l-[1-(13)C]phenylalanine oxidation. RESULTS The mean parenteral lysine requirement determined by F(13)CO(2) release oxidation was 104.9 mg . kg(-1) . d(-1) (upper and lower CIs: 120.6 and 89.1 mg . kg(-1) . d(-1), respectively). The mean lysine parenteral requirement determined by phenylalanine oxidation was 117.6 mg . kg(-1) . d(-1) (upper and lower CIs: 157.5 and 77.6 mg . kg(-1) . d(-1), respectively). Graded intakes of lysine had no effect on phenylalanine flux. CONCLUSION We recommend a mean lysine requirement for the postsurgical PN-fed neonate of 104.9 mg . kg(-1) . d(-1), which is 32-43% of the lysine concentration presently found in commercial PN solutions (246-330 mg . kg(-1) . d(-1)). This trial was registered at clinicaltrials.gov as NCT00779753.
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Affiliation(s)
- Karen P Chapman
- Research Institute, The Hospital for Sick Children, Toronto, Canada
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Courtney-Martin G, Moore AM, Ball RO, Pencharz PB. The addition of cysteine to the total sulphur amino acid requirement as methionine does not increase erythrocytes glutathione synthesis in the parenterally fed human neonate. Pediatr Res 2010; 67:320-4. [PMID: 19915518 DOI: 10.1203/pdr.0b013e3181ca036f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Controversy exists as to whether the parenterally (PN) fed human neonate is capable of synthesizing adequate cysteine from methionine if the total dietary requirement for sulfur amino acid (SAA) is provided as methionine only. The goal of this study was to gather data on whether glutathione (GSH) synthesis is maximized at a methionine intake previously shown to be adequate for protein synthesis in the PN-fed human neonate. We measured GSH concentration, fractional, and absolute synthesis rate in five PN-fed human neonates. Each neonate underwent two isotope infusion studies of 7 h duration after a 2-d adaptation to the total SAA requirement (methionine only) and again after a further 2-d adaptation to the same methionine intake supplemented with cysteine at 10 mg x kg(-1) x d(-1). Cysteine supplementation did not significantly affect GSH synthesis. These data suggest that term infants are capable of synthesizing cysteine from methionine, not only for protein but also for GSH synthesis.
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Verbruggen S, Sy J, Arrivillaga A, Joosten K, van Goudoever J, Castillo L. Parenteral amino acid intakes in critically ill children: a matter of convenience. JPEN J Parenter Enteral Nutr 2010; 34:329-40. [PMID: 20093426 DOI: 10.1177/0148607109347897] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Parenteral and enteral amino acid requirements for nutrition balance and function have not been defined in critically ill children or adults. In addition to playing a role in protein synthesis, amino acids trigger signaling cascades that regulate various aspects of fuel and energy metabolism and serve as precursors for important substrates. Amino acids can also be toxic. In this study, parenteral intakes of essential and nonessential amino acids (EAAs and NEAAs) supplied to critically ill children were assessed as an initial step for further studies aimed at establishing parenteral amino acid requirements. METHODS A retrospective review was conducted to assess intakes of parenteral amino acid for 116 critically ill children, and these intakes were compared with EAA intakes recommended by the Institute of Medicine. Because there are no recommended intakes for NEAA, NEAA intakes were compared with mixed muscle protein content in the older children and breast milk amino acid content in the infants. RESULTS Parenteral EAAs were provided in amounts that exceeded recommended intakes for healthy children, except for phenylalanine and methionine, which although excessive, were given in less generous amounts. NEAAs were supplied in lower or higher amounts than the content of mixed muscle proteins or breast milk. Parenteral amino acid formulas are limited in taurine, glutamine, and asparagine despite the fact that inflammatory/immune proteins are rich in these amino acids. CONCLUSIONS Amino acid composition of parenteral formulas is variable and lacks scientific support. Parenteral amino acid intakes should be based on measured requirements to maintain nutrition and functional balance and on knowledge of toxicity.
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Affiliation(s)
- Sascha Verbruggen
- Critical Care Section, Department of Pediatrics, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA
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Tomlinson C, Rafii M, Ball RO, Pencharz P. The significance of d-isomers in stable isotope studies in humans is dependent on the age of the subject and the amino acid tracer. Metabolism 2010; 59:14-9. [PMID: 19709694 DOI: 10.1016/j.metabol.2009.06.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 06/02/2009] [Accepted: 06/29/2009] [Indexed: 11/18/2022]
Abstract
d-Amino acids (d-AAs) in stable isotope tracers may result in erroneous estimates of enrichment, particularly if urine is used as a surrogate for plasma enrichment. Previous studies suggest that a d-AA content of less than 0.2% will not result in significant error in studies with adult humans. To describe the effects of d-AA content of less than 0.2%, in 3 different AA tracers, on isotope enrichment in urine and plasma, arginine, proline, and phenylalanine (Phe) tracers were given enterally to human neonates. Enrichment was measured in urine and plasma using chiral chromatography and tandem mass spectrometry. The Phe tracer was also given parenterally to human neonates and enterally to children and adults to further characterize the d-AA effect. All isotopes had a confirmed d-AA content of less than 0.2%. Labeled d-arginine resulted in an overestimate for enrichment of 20% in plasma and 87% in urine. A smaller effect was seen for d-Phe, which resulted in a 5% overestimate for plasma and 40% in urine. d-Proline had no significant effect. Using the same Phe tracer, a developmental effect was found, with a reduction in the overestimate in children compared with infants and no effect on enrichment in adults. Investigators using commercially produced, stable isotope-labeled AAs need to be aware that there is no safe level of d contamination; a d-AA content less than 0.2% may result in significant overestimate for enrichment, even in plasma, for infants and children. This source of error can be avoided by the use of chiral chromatography.
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Affiliation(s)
- Chris Tomlinson
- Department of Paediatrics, The Hospital for Sick Children, Toronto, M5G1X8 Canada
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Elango R, Humayun MA, Ball RO, Pencharz PB. Evidence that protein requirements have been significantly underestimated. Curr Opin Clin Nutr Metab Care 2010; 13:52-7. [PMID: 19841581 DOI: 10.1097/mco.0b013e328332f9b7] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This review discusses recent evidence that suggests a significant underestimation of protein requirements in adult humans. RECENT FINDINGS Traditionally, total protein requirements for humans have been determined using nitrogen balance. The recent Dietary Reference Intake recommendations for mean and population-safe intakes of 0.66 and 0.8 g/kg/day, respectively, of high-quality protein in adult humans are based on a meta-analysis of nitrogen balance studies using single linear regression analysis. We reanalyzed existing nitrogen balance studies using two-phase linear regression analysis and obtained mean and safe protein requirements of 0.91 and 0.99 g/kg/day, respectively. The two-phase linear regression analysis is considered more appropriate for biological analysis of dose-response curves. Considering the inherent problems associated with the nitrogen balance method, we developed an alternative method, the indicator amino acid oxidation technique, to determine protein requirements The mean and population-safe requirements in adult men were determined to be 0.93 and 1.2 g/kg/day and are 41 and 50%, respectively, higher than the current Dietary Reference Intakes recommendations. SUMMARY The indicator amino acid oxidation-based requirement values of 0.93 and 1.2 g protein/kg/day and the reanalysis of existing nitrogen balance studies are significantly higher than current recommendations. Therefore, there is an urgent need to reassess recommendations for protein intake in adult humans.
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Affiliation(s)
- Rajavel Elango
- The Research Institute, The Hospital for Sick Children, Toronto, Canada
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Elango R, Humayun MA, Ball RO, Pencharz PB. Indicator amino acid oxidation is not affected by period of adaptation to a wide range of lysine intake in healthy young men. J Nutr 2009; 139:1082-7. [PMID: 19369367 DOI: 10.3945/jn.108.101147] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The number of days of adaptation to a specific amino acid intake required prior to the determination of amino acid requirements using the indicator amino acid oxidation method (IAAO) is still in debate. In this study, our objective was to determine whether adaptation for 8 h, 3 d, and 7 d to a wide range of lysine intakes had any effect on the oxidation of the indicator amino acid, l-[1-(13)C]phenylalanine, to (13)CO(2) (F(13)CO(2)). Five healthy young men randomly received each of 4 levels of lysine (5, 20, 35, and 70 mg x kg(-1) x d(-1)) along with an amino acid mixture to achieve a protein intake of 1.0 g x kg(-1) x d(-1) and energy intake of 1.5x resting energy expenditure during 4 separate 7-d study periods. IAAO studies were conducted on d 1, 3, and 7. During each study day, oral consumption of l-[1-(13)C]phenylalanine was followed by collection of breath for F(13)CO(2) and plasma for measurement of phenylalanine enrichment. F(13)CO(2) was affected by lysine intake but did not differ among adaptation periods of 8 h, 3 d, or 7 d. Phenylalanine flux was not significantly affected by period of adaptation. These results suggest that the minimally invasive IAAO model, where participants are adapted prior to protein intake for 2 d followed by study day adaptation to the test amino acid intake for 8 h, may be sufficient to estimate individual amino acid requirements in healthy young men.
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Affiliation(s)
- Rajavel Elango
- The Research Institute, The Hospital for Sick Children, Toronto M5G 1X8, Canada
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Chapman KP, Courtney-Martin G, Moore AM, Ball RO, Pencharz PB. Threonine requirement of parenterally fed postsurgical human neonates. Am J Clin Nutr 2009; 89:134-41. [PMID: 19056607 DOI: 10.3945/ajcn.2008.26654] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The threonine requirement of human neonates who receive parenteral nutrition (PN) has not been determined experimentally. OBJECTIVE The objective was to determine the parenteral threonine requirement for human neonates by using the minimally invasive indicator amino acid oxidation technique with L-[1-(13)C]phenylalanine as the indicator amino acid. DESIGN Nine postsurgical neonates were randomly assigned to 16 threonine intakes ranging from 10 to 100 mg . kg(-1) . d(-1). Breath and urine samples were collected at baseline and at plateau for (13)CO(2) and amino acid enrichment, respectively. The mean threonine requirement was determined by applying a 2-phase linear regression crossover analysis to the measured rates of (13)CO(2) release (F(13)CO(2)) and L-[1-(13)C]phenylalanine oxidation. RESULTS The mean threonine parenteral requirement determined by using phenylalanine oxidation was 37.6 mg . kg(-1) . d(-1) (upper and lower confidence limits, respectively: 29.9 and 45.2 mg . kg(-1) . d(-1)) and by using F(13)CO(2) oxidation was 32.8 mg . kg(-1) . d(-1) (upper and lower confidence limits, respectively: 29.7 and 35.9 mg . kg(-1) . d(-1)). Graded intakes of threonine had no effect on phenylalanine flux. CONCLUSION This is the first study to report on the threonine requirement for human neonates receiving PN. We found that the threonine requirement for postsurgical PN-fed neonates is 22-32% of the content of threonine that is presently found in commercial PN solutions (111-165 mg . kg(-1) . d(-1)).
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Affiliation(s)
- Karen P Chapman
- Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
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