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Paoletti A, Courtney-Martin G, Elango R. Determining amino acid requirements in humans. Front Nutr 2024; 11:1400719. [PMID: 39091679 PMCID: PMC11291443 DOI: 10.3389/fnut.2024.1400719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 07/05/2024] [Indexed: 08/04/2024] Open
Abstract
Amino acids form the building blocks of body protein. Dietary protein sources provide the amino acids needed, but protein sources vary widely in amio acid composition. To ensure humans can meet body demands for amino acids, amino acid intake recommendations are provided by the Dietary Reference Intakes (DRI) and by Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU). Current amino acid intake recommendations, however, are based on data collected predominantly from young adult males. The development of the minimally invasive indicator amino acid oxidation (IAAO) method has permitted the evaluation of amino acid requirements in various vulnerable populations. The purpose of this review is to discuss recent amino acid requirement studies in school-age children, pregnant females and the elderly determined using the IAAO technique. These requirements will help to inform evidence-based recommendations that will help to guide dietary guidelines.
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Affiliation(s)
- Alyssa Paoletti
- Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children, Toronto, ON, Canada
- Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada
- Department of Kinesiology, University of Toronto, Toronto, ON, Canada
| | - Rajavel Elango
- Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
- BC Children’s Hospital Research Institute, BC Children’s Hospital, Vancouver, BC, Canada
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Millward DJ. Post-prandial tracer studies of protein and amino acid utilisation: what can they tell us about human amino acid and protein requirements? Br J Nutr 2024; 131:2005-2030. [PMID: 38606599 PMCID: PMC11361918 DOI: 10.1017/s0007114524000734] [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: 11/27/2023] [Revised: 02/26/2024] [Accepted: 03/13/2024] [Indexed: 04/13/2024]
Abstract
Nitrogen balance (NB), the principal methodology used to derive recommendations for human protein and amino acid requirements, has been widely criticised, and calls for increased protein and amino acid requirement recommendations have been made, often on the basis of post-prandial amino acid tracer kinetic studies of muscle protein synthesis, or of amino acid oxidation. This narrative review considers our knowledge of the homeostatic regulation of the FFM throughout the diurnal cycle of feeding and fasting and what can and has been learnt from post-prandial amino acid tracer studies, about amino acid and protein requirements. Within the FFM, muscle mass in well fed weight-stable adults with healthy lifestyles appears fixed at a phenotypic level within a wide range of habitual protein intakes. However homoeostatic regulation occurs in response to variation in habitual protein intake, with adaptive changes in amino acid oxidation which influence the magnitude of diurnal losses and gains of body protein. Post-prandial indicator amino acid oxidation (IAAO) studies have been introduced as an alternative to NB and to the logistically complex 24 h [13C-1] amino acid balance studies, for assessment of protein and amino acid requirements. However, a detailed examination of IAAO studies shows both a lack of concern for homeostatic regulation of amino acid oxidation and major flaws in their design and analytical interpretation, which seriously constrain their ability to provide reliable values. New ideas and a much more critical approach to existing work is needed if real progress is to be made in the area.
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Affiliation(s)
- D. Joe Millward
- Department of Nutritional Sciences, School of Biosciences & Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
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Gunarathne R, Guan X, Feng T, Zhao Y, Lu J. L-lysine dietary supplementation for childhood and adolescent growth: Promises and precautions. J Adv Res 2024:S2090-1232(24)00202-9. [PMID: 38740261 DOI: 10.1016/j.jare.2024.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 05/06/2024] [Accepted: 05/09/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND L-lysine (lysine) is an essential amino acid that plays a vital role in human nutrition. It serves as a key component in protein synthesis and fulfills critical roles in various physiological activities. For decades, lysine supplements have been extensively used to promote the growth and development of children, particularly in developing countries where cereal-based diets are everyday staples. AIM OF THE REVIEW This review aims to provide an overview of the overall effectiveness of lysine supplements concerning the growth of children and adolescents. Additionally, it addresses the potential precautions that should be considered when using lysine supplements in this context. KEY SCIENTIFIC CONCEPTS OF REVIEW Receiving lysine oral supplements and lysine-fortified cereal diets were observed to enhance nitrogen retention and improve anthropometric measurements such as height, weight, Z-scores, body mass index, and skinfold thickness. Furthermore, lysine positively influenced the children's developmental quotient and various serological biochemical parameters, such as hormones, immunological indicators, proteins, bone metabolic indicators, and red blood cell parameters. These supplements are generally considered clinically safe, with no reported toxicity where the related side effects are limited to subjective gastrointestinal tract symptoms. It is essential to be cautious about excessive intake of lysine, as it can lead to an imbalance of amino acids, thereby potentially suppressing its intended benefits. When used with appropriate precautions, lysine can serve as a safe supplement with promising benefits for the growth of children and adolescents. Nevertheless, further contemporary research studies on lysine supplementation would be insightful and valuable in better understanding its optimal use, potential benefits, and safety in promoting growth.
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Affiliation(s)
- Rasika Gunarathne
- Auckland Bioengineering Institute, the University of Auckland, Auckland 1142, New Zealand
| | - Xiao Guan
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Tao Feng
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201400, China
| | - Yu Zhao
- School of Life Sciences, Shanghai Normal University, Shanghai 200042, China
| | - Jun Lu
- Auckland Bioengineering Institute, the University of Auckland, Auckland 1142, New Zealand; School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China; Maurice Wilkins Centre for Biodiscovery, Auckland, New Zealand; Department of Food and Agriculture Technology, Yangtze Delta Region Institute of Tsinghua University, Zhejiang, Jiaxing 314006, China.
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Weiler M, Hertzler SR, Dvoretskiy S. Is It Time to Reconsider the U.S. Recommendations for Dietary Protein and Amino Acid Intake? Nutrients 2023; 15:838. [PMID: 36839196 PMCID: PMC9963165 DOI: 10.3390/nu15040838] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/06/2023] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
Since the U.S. Institute of Medicine's recommendations on protein and amino acid intake in 2005, new information supports the need to re-evaluate these recommendations. New lines of evidence include: (1) re-analysis/re-interpretation of nitrogen balance data; (2) results from indicator amino acid oxidation studies; (3) studies of positive functional outcomes associated with protein intakes higher than recommended; (4) dietary guidance and protein recommendations from some professional nutrition societies; and (5) recognition that the synthesis of certain dispensable amino acids may be insufficient to meet physiological requirements more often than previously understood. The empirical estimates, theoretical calculations and clinical functional outcomes converge on a similar theme, that recommendations for intake of protein and some amino acids may be too low in several populations, including for older adults (≥65 years), pregnant and lactating women, and healthy children older than 3 years. Additional influential factors that should be considered are protein quality that meets operational sufficiency (adequate intake to support healthy functional outcomes), interactions between protein and energy intake, and functional roles of amino acids which could impact the pool of available amino acids for use in protein synthesis. Going forward, the definition of "adequacy" as it pertains to protein and amino acid intake recommendations must take into consideration these critical factors.
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Affiliation(s)
- Mary Weiler
- Scientific and Medical Affairs, Abbott Nutrition, 2900 Easton Square Place, Columbus, OH 43219, USA
| | - Steven R. Hertzler
- Scientific and Medical Affairs, Abbott Nutrition, 2900 Easton Square Place, Columbus, OH 43219, USA
| | - Svyatoslav Dvoretskiy
- Department of Kinesiology and Community Health, University of Illinois, Urbana-Champaign, IL 61801, USA
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Saleemani H, Horvath G, Stockler-Ipsiroglu S, Elango R. Determining ideal balance among branched-chain amino acids in medical formula for Propionic Acidemia: A proof of concept study in healthy children. Mol Genet Metab 2022; 135:56-62. [PMID: 34969640 DOI: 10.1016/j.ymgme.2021.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 12/17/2021] [Accepted: 12/17/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Propionic Acidemia (PROP) is an inherited metabolic disorder, with defect in the enzyme propionyl-CoA carboxylase (PCC) which catalyzes catabolism of two of the branched-chain amino acids (BCAA), valine, isoleucine. Nutritional management in PROP depends on dietary protein restriction and consumption of medical formula depleted of the offending amino acids. Recently, concerns have been raised about medical formula due to imbalanced content of BCAA (high leucine - another BCAA, and no valine/isoleucine), which negatively impacts plasma concentrations of BCAA, and growth in children with PROP. OBJECTIVES AND METHODS To determine an optimal BCAA ratio at which total body protein synthesis is optimized in healthy children using the indicator amino acid oxidation method (oxidation of L-13C-Phenylalanine to 13CO2). This was accomplished by reducing leucine intake gradually from the current high dose in medical formula, in order to compare protein synthesis, under different BCAA ratios. RESULTS A total of 8 healthy children were studied, completing 42 study days. Significant differences in F13CO2 with different BCAA ratios were found. BCAA ratio (leucine: isoleucine: valine) 1:0:0 was associated with the highest F13CO2 (low protein synthesis) compared to other ratios. By reducing leucine intake, and isoleucine and valine at minimum PROP recommendations, BCAA ratio between1:0.26:0.28 to 1:0.35:0.4 was associated with optimal protein synthesis. CONCLUSION BCAA ratio of 1:0:0, present in medical formula limited total body protein synthesis. A balanced BCAA ratio was found between 1:0.26:0.28 and 1:0.35:0.4 (leucine:isoleucine:valine). Future research is needed to test this optimal BCAA ratio for optimizing protein synthesis in patients with PROP. SYNOPSIS The article describes a proof-of-concept study done on healthy school-aged children testing different ratios of branched chain amino acid (BCAA, leucine:isoleucine:valine), in order to determine an optimal ratio at which total body protein synthesis is improved and has implications for dietary management of children with Propionic Acidemia (PROP).
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Affiliation(s)
- Haneen Saleemani
- BC Children's Hospital Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada; Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada; Faculty of Applied Medical Sciences, Department of Clinical Nutrition, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Gabriella Horvath
- BC Children's Hospital Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada; Department of Pediatrics, University of British Columbia, Vancouver, Canada
| | - Sylvia Stockler-Ipsiroglu
- BC Children's Hospital Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada; Division of Biochemical Genetics, BC Children's Hospital, Vancouver, Canada; Department of Pediatrics, University of British Columbia, Vancouver, Canada
| | - Rajavel Elango
- BC Children's Hospital Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada; Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada; Department of Pediatrics, University of British Columbia, Vancouver, Canada; School of Population and Public Health, University of British Columbia, British Columbia, Canada.
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Thompson AJ, Bourke CD, Robertson RC, Shivakumar N, Edwards CA, Preston T, Holmes E, Kelly P, Frost G, Morrison DJ. Understanding the role of the gut in undernutrition: what can technology tell us? Gut 2021; 70:gutjnl-2020-323609. [PMID: 34103403 PMCID: PMC8292602 DOI: 10.1136/gutjnl-2020-323609] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 05/04/2021] [Indexed: 12/22/2022]
Abstract
Gut function remains largely underinvestigated in undernutrition, despite its critical role in essential nutrient digestion, absorption and assimilation. In areas of high enteropathogen burden, alterations in gut barrier function and subsequent inflammatory effects are observable but remain poorly characterised. Environmental enteropathy (EE)-a condition that affects both gut morphology and function and is characterised by blunted villi, inflammation and increased permeability-is thought to play a role in impaired linear growth (stunting) and severe acute malnutrition. However, the lack of tools to quantitatively characterise gut functional capacity has hampered both our understanding of gut pathogenesis in undernutrition and evaluation of gut-targeted therapies to accelerate nutritional recovery. Here we survey the technology landscape for potential solutions to improve assessment of gut function, focussing on devices that could be deployed at point-of-care in low-income and middle-income countries (LMICs). We assess the potential for technological innovation to assess gut morphology, function, barrier integrity and immune response in undernutrition, and highlight the approaches that are currently most suitable for deployment and development. This article focuses on EE and undernutrition in LMICs, but many of these technologies may also become useful in monitoring of other gut pathologies.
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Affiliation(s)
- Alex J Thompson
- Hamlyn Centre for Robotic Surgery, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Claire D Bourke
- Blizard Institute, Barts & The London School of Medicine, Queen Mary University of London, London, UK
| | - Ruairi C Robertson
- Blizard Institute, Barts & The London School of Medicine, Queen Mary University of London, London, UK
| | - Nirupama Shivakumar
- Division of Nutrition, St John's National Academy of Health Sciences, Bangalore, Karnataka, India
| | | | - Tom Preston
- Stable Isotope Biochemistry Laboratory, Scottish Universities Environmental Research Centre, East Kilbride, UK
| | - Elaine Holmes
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Paul Kelly
- Blizard Institute, Barts & The London School of Medicine, Queen Mary University of London, London, UK
- Tropical Gastroenterology and Nutrition Group, University of Zambia School of Medicine, Lusaka, Zambia
| | - Gary Frost
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Douglas J Morrison
- Stable Isotope Biochemistry Laboratory, Scottish Universities Environmental Research Centre, East Kilbride, UK
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Hayamizu K, Oshima I, Nakano M. Comprehensive Safety Assessment of l-Lysine Supplementation from Clinical Studies: A Systematic Review. J Nutr 2020; 150:2561S-2569S. [PMID: 33000161 DOI: 10.1093/jn/nxaa218] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 06/12/2020] [Accepted: 07/01/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Despite the widespread use of l-lysine in dietary supplements, the safety information pertinent to excessive l-lysine ingestion is limited and, to the best of our knowledge, there is no published systematic review of safety. OBJECTIVE The objective of this study was to assess the clinical safety of l-lysine supplementation of a regular diet. METHODS We searched PubMed, Cochrane Library, Ichushi Web, and EBSCOhost using the relevant keywords, "l-lysine" and "clinical trial." To investigate all adverse events observed during intervention trials, we included all intervention studies with orally ingested l-lysine without restricting background factors, environment, study designs, and sample sizes. RESULTS We identified 71 articles, which included 3357 study subjects. The l-lysine doses ranged from 16.8 to 17.5 g/d, and the dosing period ranged from 1 to 1095 d. The observed adverse events were mainly subjective gastrointestinal tract symptoms; however, the risk analysis for incidence of gastrointestinal symptoms was not statistically significant (risk ratio of 1.02). CONCLUSION The provisional no-observed-adverse-effect level in healthy human subjects was based on gastrointestinal symptoms and identified at 6.0 g/d. The review protocol was registered at umin.ac.jp as UMIN000028914 before the beginning of the study.
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Affiliation(s)
- Kohsuke Hayamizu
- Laboratory of Food Chemistry, Yokohama University of Pharmacy, Yokohama, Japan
| | - Ikuyo Oshima
- Laboratory of Food Chemistry, Yokohama University of Pharmacy, Yokohama, Japan
| | - Makoto Nakano
- Laboratory of Food Chemistry, Yokohama University of Pharmacy, Yokohama, Japan
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Bandegan A, Courtney-Martin G, Rafii M, Pencharz PB, Lemon PWR. Indicator amino acid oxidation protein requirement estimate in endurance-trained men 24 h postexercise exceeds both the EAR and current athlete guidelines. Am J Physiol Endocrinol Metab 2019; 316:E741-E748. [PMID: 30779631 DOI: 10.1152/ajpendo.00174.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Despite studies indicating increased protein requirements in strength-trained or endurance-trained (ET) individuals, the Institute of Medicine has concluded that "no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise," and the controversy regarding exercise effects on protein requirements continues. The objective of this study was to determine the dietary protein requirement of healthy young ET men (≥1 yr training experience) 24 h post exercise (to minimize any acute effects of the previous training session) by measuring the oxidation of ingested l-[1-13C]phenylalanine to 13CO2 in response to graded intakes of protein (indicator amino acid oxidation technique). Eight men [maximal oxygen consumption 64.1 ml·kg-1·min-1 (SD 3.7)] were each studied 24 h postexercise repeatedly with protein intakes ranging from 0.3 to 3.5 g·kg-1·day-1. Protein was fed as an amino acid mixture based on the protein pattern in egg, except for phenylalanine and tyrosine, which were maintained at constant amounts across all protein intakes. For 2 days before the study day, all participants consumed 1.6 g protein·kg-1·day-1. The estimated average requirement (EAR) for protein was determined by applying a nonlinear mixed-effects change-point regression analysis to F13CO2 (label tracer oxidation in 13CO2 breath), which identified a breakpoint in the F13CO2 in response to the graded amounts of protein. The EAR for protein and the upper 95% confidence interval were 2.1 and 2.6 g·kg-1·day-1, respectively. These data suggest that the protein EAR for ET men 24 h postexercise exceeds the Institute of Medicine EAR and established athlete guidelines by ~3.5- and 1.3-fold, respectively.
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Affiliation(s)
- Arash Bandegan
- Exercise Nutrition Research Laboratory, School of Kinesiology, Western University , London, Ontario , Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children , Toronto, Ontario , Canada
- Faculty of Kinesiology & Physical Education, University of Toronto , Toronto, Ontario , Canada
- Department of Nutritional Sciences, University of Toronto , Toronto, Ontario , Canada
| | - Mahroukh Rafii
- Research Institute, Hospital for Sick Children , Toronto, Ontario , Canada
| | - Paul B Pencharz
- Research Institute, Hospital for Sick Children , Toronto, Ontario , Canada
- Department of Nutritional Sciences, University of Toronto , Toronto, Ontario , Canada
- Department of Paediatrics and Nutrition Science, University of Toronto , Toronto, Ontario , Canada
| | - Peter W R Lemon
- Exercise Nutrition Research Laboratory, School of Kinesiology, Western University , London, Ontario , Canada
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Hayamizu K, Oshima I, Fukuda Z, Kuramochi Y, Nagai Y, Izumo N, Nakano M. Safety assessment of L-lysine oral intake: a systematic review. Amino Acids 2019; 51:647-659. [PMID: 30661148 DOI: 10.1007/s00726-019-02697-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/08/2019] [Indexed: 10/27/2022]
Abstract
Currently, the use of amino acids in supplements and functional foods is increasing globally. However, there are no guidelines for the upper limit of ingestion for the safe use of these amino acids. Safety evaluation of chemical substances is generally performed through non-clinical and clinical studies. However, amino acids that have these safety data are limited. Therefore, we used a systematic review approach for evaluating the safety of amino acids. In the present study, we evaluated the safety of L-lysine added to an ordinary diet in humans. Using PubMed, Cochrane Library, Ichushi Web, and EBSCOhost as search databases, we comprehensively searched human studies on oral ingestion of L-lysine. Ultimately, 71 studies were selected for evaluation. Of these, 12 studies were of relatively high quality with Jadad scores ≥ 3. The dose range of L-lysine in the selected studies was 16.8-17,500 mg/day, and the range of dosing period was 1-1095 days. The observed adverse events were mainly subjective symptoms related to the gastrointestinal tract such as nausea, stomachache, and diarrhea. The provisional no-observed-adverse-effect level obtained based on these gastrointestinal symptoms was 6000 mg/person/day. Integrated analysis of the risk for developing gastrointestinal symptoms revealed that the risk ratio was 1.02 (95% CI, 0.96-1.07; p = 0.49); thus, no significant increase was observed. (UMIN000028914).
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Affiliation(s)
- Kohsuke Hayamizu
- Laboratory of Food Chemistry, Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama, Kanagawa, 245-0066, Japan.
| | - Ikuyo Oshima
- Laboratory of Food Chemistry, Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama, Kanagawa, 245-0066, Japan
| | - Zesoku Fukuda
- Laboratory of Food Chemistry, Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama, Kanagawa, 245-0066, Japan
| | - Yui Kuramochi
- Laboratory of Food Chemistry, Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama, Kanagawa, 245-0066, Japan
| | - Yuki Nagai
- Laboratory of Food Chemistry, Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama, Kanagawa, 245-0066, Japan
| | - Nobuo Izumo
- General Health Medical Center, Yokohama University of Pharmacy, Yokohama, Japan
| | - Makoto Nakano
- Laboratory of Food Chemistry, Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama, Kanagawa, 245-0066, Japan.,General Health Medical Center, Yokohama University of Pharmacy, Yokohama, Japan
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Shivakumar N, Minocha S, Kurpad AV. Protein quality & amino acid requirements in relation to needs in India. Indian J Med Res 2018; 148:557-568. [PMID: 30666983 PMCID: PMC6366268 DOI: 10.4103/ijmr.ijmr_1688_18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Indexed: 11/04/2022] Open
Abstract
The relevance of protein and its constituent amino acids (AAs) in the structure and function of the human body is well known. Accumulating evidence has conferred specific functional and regulatory roles for individual AAs, adding relevance to their requirements across different age groups. The methods for measuring AA requirements have progressed from the classical nitrogen balance to the current stable isotope-based AA balance methods. Requirements of most of the indispensable AA (IAA) have been estimated in healthy Indian population by the best available balance method and has shown to be higher than earlier 1985 WHO/FAO/UNU (World Health Organization/Food and Agriculture Organization/United Nations University) recommendations. In addition, potential changes in the requirement, through adaptation to chronic undernutrition or to infection, have also been evaluated. In 2007, the WHO/FAO/UNU released a recommendation that increased the daily IAA requirement, based on primary evidence from Indian balance studies. This meant that to ensure that the new IAA requirements were met, individual foods or mixed diets needed to be assessed for their protein quality, or their ability to deliver the required amount of IAA. The recent FAO report on protein quality evaluation recommends the use of a new chemical AA score, the digestible IAA score (DIAAS), to replace the earlier protein digestibility corrected AA score. The DIAAS requires the determination of individual AA digestibility at the ileal level. A minimally invasive dual stable isotope tracer-based approach has been developed in India and has been used to determine digestibility of various foods in Indian adults and children. The increase in IAA requirements and subsequent protein quality requirements have implications for national regulatory frameworks, growth and development, and in turn, for economic and agricultural policy.
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Affiliation(s)
| | - Sumedha Minocha
- Division of Nutrition, St. John's Research Institute, Bengaluru, India
| | - Anura V. Kurpad
- Department of Physiology, St. John's Medical College, Bengaluru, India
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Kashyap S, Shivakumar N, Varkey A, Duraisamy R, Thomas T, Preston T, Devi S, Kurpad AV. Ileal digestibility of intrinsically labeled hen's egg and meat protein determined with the dual stable isotope tracer method in Indian adults. Am J Clin Nutr 2018; 108:980-987. [PMID: 30272112 PMCID: PMC6250983 DOI: 10.1093/ajcn/nqy178] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 07/04/2018] [Indexed: 01/18/2023] Open
Abstract
Background Protein quality assessment through the Digestible Indispensable Amino Acid Score requires accurate measurements of true ileal protein and amino acid digestibility, for which a dual isotope technique was recently developed. However, the ileal digestibility of indispensable amino acids (IAA) in humans from high-quality proteins is not well known. Objective The aim of this study was to intrinsically label hen's egg and meat protein by the use of uniformly 2H-labeled amino acids, and to measure their true ileal indispensable amino acid (IAA) digestibility via the dual isotope method in humans. Design 2H-labeled lyophilized boiled egg white protein, whole boiled egg, and cooked meat were obtained from layer hens (BV-300) administered a uniformly 2H-labeled amino acid mix orally for 35 d with their daily feed. The ileal IAA digestibility of these proteins was determined with reference to digestibility of previously characterized [U-13C]spirulina in a dual tracer method in healthy Indian subjects whose intestinal health was measured by the plasma kynurenine-to-tryptophan (KT) ratio. Results All subjects had normal KT ratios. The mean ± SD true ileal IAA digestibility of 2H-labeled egg white protein, whole boiled egg, and cooked meat was 86.3% ± 4.6%, 89.4% ± 4.5%, and 92.0% ± 2.8%, respectively. Leucine digestibility correlated with the KT ratio (r = -0.772; P = 0.009). Conclusions Uniformly 2H-labeled hen's egg and meat protein can be used to measure ileal IAA digestibility by the dual isotope tracer approach in humans. The mean IAA digestibility values for these high-quality proteins in the healthy Indians studied were similar to values obtained in earlier human and animal experiments. Leucine digestibility in these meal matrices correlated with the KT ratio, but this aspect needs further evaluation. This trial was registered at the Clinical Trials Registry of India (http://ctri.nic.in) as CTRI/2018/03/012265.
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Affiliation(s)
- Sindhu Kashyap
- Division of Nutrition, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
| | - Nirupama Shivakumar
- Departments of Physiology, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
| | - Aneesia Varkey
- Division of Nutrition, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
| | - Rajendran Duraisamy
- Indian Council of Agricultural Research-National Institute of Animal Nutrition and Physiology, Adugodi, Bangalore, India
| | - Tinku Thomas
- Departments of Biostatistics, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
| | - Thomas Preston
- Scottish Universities Environmental Research Centre, East Kilbride, Scotland, United Kingdom
| | - Sarita Devi
- Division of Nutrition, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
| | - Anura V Kurpad
- Division of Nutrition, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India,Departments of Physiology, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India,Address correspondence to AVK (e-mail: )
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Pencharz PB, Elango R, Wolfe RR. Recent developments in understanding protein needs - How much and what kind should we eat? Appl Physiol Nutr Metab 2016; 41:577-80. [PMID: 27109436 DOI: 10.1139/apnm-2015-0549] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel method has been developed to determine protein requirements, which is called indicator amino acid oxidation (IAAO). This technique has been validated by comparison with the "gold standard" nitrogen balance. Using IAAO we have shown that minimum protein requirements have been underestimated by 30%-50%. The National Academy of Sciences has for macro-nutrients proposed "Acceptable Macronutrient Distribution Ranges", which for protein is 10% to 35% of total energy. In practice, we suggest 1.5-2.2 g/(kg·day) of a variety of high-quality proteins.
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Affiliation(s)
- Paul B Pencharz
- a Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada.,b Department of Paediatrics and Nutritional Sciences, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Rajavel Elango
- c Department of Pediatrics, University of British Columbia, Vancouver, BC V6T 1Z9, Canada.,d School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada.,e Child and Family Research Institute, BC Children's Hospital, Room 170A, 950 West 28th Avenue, Vancouver, BC V5Z 4H4, Canada
| | - Robert R Wolfe
- f Department of Geriatrics, Center for Translational Research in Aging and Longevity, Reynolds Institute on Aging, University of Arkansas for Medical Sciences, 4301 W Markham Street, #806, Little Rock, AR 72205, USA
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Pillai RR, Elango R, Ball RO, Kurpad AV, Pencharz PB. Lysine requirements of moderately undernourished school-aged Indian children are reduced by treatment for intestinal parasites as measured by the indicator amino acid oxidation technique. J Nutr 2015; 145:954-9. [PMID: 25761501 DOI: 10.3945/jn.114.208439] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/19/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Lysine requirements of well-nourished children from developing regions have been found to be similar to those of children from developed regions (33.5 mg · kg⁻¹ · d⁻¹). However, intestinal parasites have been shown to increase lysine requirements in undernourished adults, and it is not known if a similar phenomenon occurs in undernourished children from poor and unsanitary environments. OBJECTIVE Our objective was to measure the lysine requirement of moderately undernourished school-aged Indian children by the indicator amino acid oxidation technique before and after successful treatment for intestinal parasites. METHODS Twenty-one undernourished school-aged children (∼8 y of age) with z scores between -2 SD and -3 SD for height-for-age or weight-for-age, who tested positive for intestinal parasites, were studied before and after successful antiparasite treatment. Children were fed any 2 of 7 levels of lysine intakes (5, 15, 25, 35, 50, 65, and 80 mg · kg⁻¹ · d⁻¹) in random order. The lysine requirement was determined by applying a 2-phase linear regression crossover analysis on the fractional oxidation rate of the tracer L-[1-¹³C] phenylalanine in response to the graded lysine intakes. RESULTS The lysine requirement of undernourished children with intestinal parasite infestations was determined to be 42.8 mg · kg⁻¹ · d⁻¹ (95% CI: 32.6, 53.1 mg · kg⁻¹ · d⁻¹), and after successful antiparasitic treatment it was determined to be 35.5 mg · kg⁻¹ · d⁻¹ (95% CI: 25.5, 45.5 mg · kg⁻¹ · d⁻¹). The results were significantly different (P < 0.05), although the 95% CIs overlapped. CONCLUSIONS The lysine requirement in undernourished children is similar to that of well-nourished children, and intestinal parasitic infestation increased the lysine requirement by ∼20%.
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Affiliation(s)
- Raja R Pillai
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Rajavel Elango
- The Research Institute, Hospital for Sick Children, Toronto, Canada;
| | - Ronald O Ball
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Canada; and
| | - Anura V Kurpad
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Paul B Pencharz
- The Research Institute, Hospital for Sick Children, Toronto, Canada; Department of Pediatrics and Nutritional Sciences, University of Toronto, Toronto, Canada
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Stephens TV, Payne M, Ball RO, Pencharz PB, Elango R. Protein requirements of healthy pregnant women during early and late gestation are higher than current recommendations. J Nutr 2015; 145:73-8. [PMID: 25527661 DOI: 10.3945/jn.114.198622] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Adequate maternal dietary protein intake is necessary for healthy pregnancy. However, current protein intake recommendations for healthy pregnant women are based on factorial calculations of nitrogen balance data derived from nonpregnant adults. Thus, an estimate of protein requirements based on pregnancy-specific data is needed. OBJECTIVE The objective of this study was to determine protein requirements of healthy pregnant women at 11-20 (early) and 31-38 (late) wk of gestation through use of the indicator amino acid oxidation method. METHODS Twenty-nine healthy women (24-37 y) each randomly received a different test protein intake (range: 0.22-2.56 g · kg(-1) · d(-1)) during each study day in early (n = 35 observations in 17 women) and late (n = 43 observations in 19 women) gestation; 7 women participated in both early and late gestation studies. The diets were isocaloric and provided energy at 1.7 × resting energy expenditure. Protein was given as a crystalline amino acid mixture based on egg protein composition, except phenylalanine and tyrosine, which were maintained constant across intakes. Protein requirements were determined by measuring the oxidation rate of L-[1-(13)C]phenylalanine to (13)CO2 (F(13)CO2). Breath and urine samples were collected at baseline and isotopic steady state. Linear regression crossover analysis identified a breakpoint (requirement) at minimal F(13)CO2 in response to different protein intakes. RESULTS The estimated average requirement (EAR) for protein in early and late gestation was determined to be 1.22 (R(2) = 0.60; 95% CI: 0.79, 1.66 g · kg(-1) · d(-1)) and 1.52 g · kg(-1) · d(-1) (R(2) = 0.63; 95% CI: 1.28, 1.77 g · kg(-1) · d(-1)), respectively. CONCLUSIONS These estimates are considerably higher than the EAR of 0.88 g · kg(-1) · d(-1) currently recommended by the Dietary Reference Intakes. To our knowledge, this study is the first to directly estimate gestational stage-specific protein requirements in healthy pregnant women and suggests that current recommendations based on factorial calculations underestimate requirements. This trial was registered at clinicaltrials.gov as NCT01784198.
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Affiliation(s)
- Trina V Stephens
- Child & Family Research Institute, British Columbia Children's Hospital, Vancouver, Canada Department of Pediatrics, University of British Columbia, Vancouver, Canada
| | - Magdalene Payne
- Child & Family Research Institute, British Columbia Children's Hospital, Vancouver, Canada Department of Pediatrics, University of British Columbia, Vancouver, Canada
| | - Ronald O Ball
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Paul B Pencharz
- The Research Institute, Hospital for Sick Children, Toronto, Canada; and
| | - Rajavel Elango
- Child & Family Research Institute, British Columbia Children's Hospital, Vancouver, Canada Department of Pediatrics, University of British Columbia, Vancouver, Canada School of Population and Public Health, University of British Columbia, Canada
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15
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Dietary crude protein intake influences rates of whole-body protein synthesis in weanling horses. Vet J 2014; 202:236-43. [DOI: 10.1016/j.tvjl.2014.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 06/02/2014] [Accepted: 06/05/2014] [Indexed: 11/20/2022]
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Tang M, McCabe GP, Elango R, Pencharz PB, Ball RO, Campbell WW. Assessment of protein requirement in octogenarian women with use of the indicator amino acid oxidation technique. Am J Clin Nutr 2014; 99:891-8. [PMID: 24429540 PMCID: PMC3953883 DOI: 10.3945/ajcn.112.042325] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Data on the protein requirements of elderly adults are limited, because it is impractical to conduct repeated nitrogen balance protocols in these vulnerable humans. OBJECTIVE This study was designed to determine the dietary protein requirement of elderly women by using the recently developed minimally invasive indicator amino acid oxidation (IAAO) technique. DESIGN Six white women aged 80-87 y [mean ± SEM: 82 ± 1 y and body mass index (in kg/m²) 26 ± 2] completed a 3-d protocol 7 times. Each woman consumed an adaptation diet for 2 d and on day 3 consumed a complete test diet with a crystalline amino acid mixture containing 1 of 7 protein intakes (0.1, 0.3, 0.6, 0.9, 1.2, 1.5, or 1.8 g · kg⁻¹ · d⁻¹) tested randomly. A group-based protein requirement was assessed by using a nonlinear mixed model of protein intake and L-[1-¹³C]phenylalanine oxidation. The breakpoint, at which there was no further decline in the rate of appearance of ¹³C in the breath, was used as an index of the mean protein requirement. RESULTS The mean protein requirement (95% CI) was 0.85 (0.60, 1.09) g · kg⁻¹ · d⁻¹. This requirement is 29% higher than the current Estimated Average Requirement (EAR) for adults of 0.66 g · kg⁻¹ · d⁻¹ based on the nitrogen balance technique, although the 95% CI includes the current EAR. The corresponding adequate protein allowance of 1.15 (0.77, 1.54) g · kg⁻¹ · d⁻¹ is 44% higher, although the 95% CI includes the Recommended Dietary Allowance (RDA) of 0.80 g · kg⁻¹ · d⁻¹. CONCLUSIONS Notwithstanding uncertainty about the validity of the use of the IAAO technique to assess protein requirements, the results of this study with octogenarian women suggest that the current EAR and RDA for elderly women may be underestimated. The limitations of this short-term, noninvasive method underscore the need for new research that uses alternative experimental designs and measuring physiologic, morphologic, and health-related outcomes.
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Affiliation(s)
- Minghua Tang
- Departments of Nutrition Science (MT and WWC) and Statistics (GPM), Purdue University, West Lafayette, IN; the Department of Pediatrics, University of British Columbia, Vancouver, Canada (RE); the Department of Paediatrics and Nutrition Science, University of Toronto, Toronto, Canada (PBP); and the Department of Agricultural, Food and Nutrition Science, University of Alberta, Edmonton, Canada (ROB)
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Pencharz P, Jahoor F, Kurpad A, Michaelsen KF, Slater C, Tomé D, Weisell R. Current issues in determining dietary protein and amino-acid requirements. Eur J Clin Nutr 2014; 68:285-6. [PMID: 24424080 DOI: 10.1038/ejcn.2013.297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pregnancy and the first two years of life are periods of rapid growth and yet the knowledge of requirements for protein and dietary indispensable amino acids is very limited. The development of carbon oxidation methods opens the way to studies that should fill these important gaps in knowledge.
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Affiliation(s)
- P Pencharz
- Department of Gastroenterology, Nutrition and Hepatology, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - F Jahoor
- Children's Nutrition Research Center, Agricultural Research Service, US Department of Agriculture, Houston, TX, USA
| | - A Kurpad
- St John's Medical College, Bangalore, Karnataka, India
| | - K F Michaelsen
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark
| | - C Slater
- IAEA, Nutritional and Health-related Environmental Studies Section, Division of Human Health, Vienna, Austria
| | - D Tomé
- AgroParisTech, UMR0914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - R Weisell
- Viale delle Ginestre 8, Ariccia (RM), Italy
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Abstract
The factorial approach is used to measure the dietary indispensable amino acid (IAA) requirements in children, although recent measurements based on the indicator amino acid oxidation (IAAO) method have begun to generate more direct evidence. Difficulties with the factorial method are that it depends on accurate estimates of the maintenance protein requirement, as well as of protein deposition during growth. Also, a value for the efficiency of utilizing dietary protein for deposition has to be selected, based on published Nitrogen (N) balance studies. In the recent 2007 WHO/FAO/UNU report, the amino acid requirement pattern for infants was taken to be similar to the amino acid composition of breast milk. For pre-school and older children, the factorial method gave values for the scoring pattern of protein that were fairly close to the earlier 1985 WHO/FAO/UNU report for children, since growth progressively became a smaller component of the factorial calculation as age progressed. However, given that there are several assumptions in the derivation of factorial estimates, direct experimental measurements of the amino acid requirement are desirable. The IAAO method, as it is non-invasive, as made it possible to measure the IAA requirements in children. Over the last decade, some of the IAA requirements have been determined by using the IAAO method in healthy school age children; however, the data on IAA requirements in developing country populations are still being conducted. In the elderly, there are not enough data to make a separate recommendation for IAA requirements from that of adults.
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Identifying recommended dietary allowances for protein and amino acids: a critique of the 2007 WHO/FAO/UNU report. Br J Nutr 2012; 108 Suppl 2:S3-21. [DOI: 10.1017/s0007114512002450] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The WHO/FAO/UNU (2007) report examines dietary protein and amino acid requirements for all age groups, protein requirements during pregnancy, lactation and catch-up growth in children, the implications of these requirements for developing countries and protein quality evaluation. Requirements were defined as the minimum dietary intake which satisfies the metabolic demand and achieves nitrogen equilibrium and maintenance of the body protein mass, plus the needs for growth in children and pregnancy and lactation in healthy women. Insufficient evidence was identified to enable recommendations for specific health outcomes. A meta analysis of nitrogen balance studies identifies protein requirements for adults 10 % higher than previous values with no influence of gender or age, consistent with a subsequently published comprehensive study. A new factorial model for infants and children, validated on the basis of the adequacy of breast milk protein intakes and involving a lower maintenance requirement value, no provision for saltatory growth and new estimates of protein deposition identifies lower protein requirements than in previous reports. Higher values for adult amino acid requirements, derived from a re-evaluation of nitrogen balance studies and new stable isotope studies, identify some cereal-based diets as being inadequate for lysine. The main outstanding issues relate to the biological implausibility of the very low efficiencies of protein utilisation used in the factorial models for protein requirements for all population groups especially pregnancy when requirements may be overestimated. Also considerable uncertainty remains about the design and interpretation of most of the studies used to identify amino acid requirement values.
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Abstract
During the past 25 years a significant amount of research has been conducted to determine amino acid requirements in humans. This is primarily due to advancements in the application of stable isotopes to examine amino acid requirements. The indicator amino acid oxidation (IAAO) method has emerged as a robust and minimally invasive technique to identify requirements. The IAAO method is based on the concept that when one indispensable dietary amino acid (IDAA) is deficient for protein synthesis, then the excess of all other IDAA, including the indicator amino acid, will be oxidized. With increasing intakes of the limiting amino acid, IAAO will decrease, reflecting increasing incorporation into protein. Once the requirement for the limiting amino acid is met there will be no further change in the indicator oxidation. The IAAO method has been systematically applied to determine most IDAA requirements in adults. The estimates are comparable to the values obtained using the more elaborate 24h-indicator amino acid oxidation and balance (24h-IAAO/IAAB) model. Due to its non-invasive nature the IAAO method has also been used to determine requirements for amino acids in neonates, children and in disease. The IAAO model has recently been applied to determine total protein requirements in humans. The IAAO method is rapid, reliable and has been used to determine amino acid requirements in different species, across the life cycle and in disease. The recent application of IAAO to determine protein requirements in humans is novel and has significant implications for dietary protein intake recommendations globally.
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Ogawa A, Naruse Y, Shigemura Y, Kobayashi Y, Suzuki I, Wada S, Hayamizu K, Kuwahata M, Kido Y. An evaluation of protein intake for metabolic demands and the quality of dietary protein in rats using an indicator amino acid oxidation method. J Nutr Sci Vitaminol (Tokyo) 2012; 57:418-25. [PMID: 22472284 DOI: 10.3177/jnsv.57.418] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Currently, protein requirements are generally determined based on nitrogen balance studies, but there are a variety of limitations associated with this method. The indicator amino acid oxidation (IAAO) method, with a theoretical base that differs widely from the nitrogen balance method, was developed as an alternative method for humans. The objective of the present study was to evaluate protein intakes for metabolic demands and protein quality, using protein itself, in rats employing the IAAO technique with L-[1-(13)C]phenylalanine. Male Wistar/ST rats (5-6 wk old) received a graded casein (4.3, 8.6, 12.9, 17.2, 21.5, 25.8%), or a wheat gluten (7.2, 10.8, 14.4, 18.0, 21.6, 25.2%) diet, along with L-[1-(13)C]phenylalanine. An isotopic plateau in breath was achieved 210 min after the start of the (13)C ingestion. The protein intakes for metabolic demands were calculated by applying a mixed-effect change-point regression model to breath (13)CO(2) data, which identified a breakpoint at minimal breath (13)CO(2) in response to graded protein intake. The protein intakes for metabolic demands determined by the IAAO method were 13.1 g/kg BW/d for casein and 18.1 g/kg BW/d for wheat gluten, showing a tendency similar to that determined by the nitrogen balance method. These results demonstrated that the IAAO method could be employed to evaluate not only the protein intakes for metabolic demands, but the dietary protein quality in freely living rats, suggesting that this method might be viable in a clinical setting.
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Affiliation(s)
- Aki Ogawa
- Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
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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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Hayamizu K, Kato M, Hattori S. Determining amino acid requirements from repeated observations on indicator amino acid oxidation method by mixed-effect change-point regression models. J Clin Biochem Nutr 2011; 49:115-20. [PMID: 21980227 PMCID: PMC3171677 DOI: 10.3164/jcbn.10-146] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 01/05/2011] [Indexed: 11/26/2022] Open
Abstract
In nutrition studies, it is often of primary interest to determine the critical threshold value of some biological quantities. To determine the amino acid requirement, the tracer approach including the indicator amino acid oxidation method is useful for the investigation of human subjects. In this approach, measurements of amino acids other than the test amino acid are often repeatedly carried out with various intakes of the test amino acid. Change-point regression models have often been applied to determine the amino acid requirement. However, within-subject dependence due to repeated measurements has not been sufficiently taken into account. In this paper, we propose a mixed-effect change-point model to estimate the amino acid requirements when utilizing the tracer approach. Inference based on Akaike Information Criteria is introduced to include selection of the optimal model and construction of a confidence interval. Our method can easily be applied with a standard software package, and we found that appropriate accounting for within-subject dependence may lead to a much narrower confidence interval. We recommend application of a mixed-effect change-point regression model to determine the amino acid requirements in studies utilizing the tracer approach.
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Affiliation(s)
- Kohsuke Hayamizu
- Human Life Science R & D Center, Nippon Suisan Kaisha Ltd., 2-6-2 Otemachi, Chiyoda-ku, Tokyo 100-8686, Japan
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