1
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Allison DB, Bier DM, Locher JL. Measurement rigor is not a substitute for design rigor in causal inference: increased physical activity does cause (modest) weight loss. Int J Obes (Lond) 2023; 47:3-4. [PMID: 36443405 DOI: 10.1038/s41366-022-01234-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 10/20/2022] [Accepted: 10/25/2022] [Indexed: 11/29/2022]
Affiliation(s)
- David B Allison
- Indiana University School of Public Health-Bloomington, 1025 E 7th Street, PH 111, Bloomington, IN, 47405, USA.
| | | | - Julie L Locher
- University of Alabama at Birmingham Department of Medicine, Birmingham, AL, USA
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2
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Achterberg C, Astrup A, Bier DM, King JC, Krauss RM, Teicholz N, Volek JS. An analysis of the recent US dietary guidelines process in light of its federal mandate and a National Academies report. PNAS Nexus 2022; 1:pgac107. [PMID: 36741454 PMCID: PMC9896931 DOI: 10.1093/pnasnexus/pgac107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 07/18/2022] [Indexed: 02/07/2023]
Abstract
The US Dietary Guidelines for Americans is an enormously influential policy that has guided US nutrition programs since 1980. During these last 40 years, some researchers have expressed concern that the guidelines are based on an insufficiently rigorous assessment of the scientific evidence, a view that was largely substantiated by a Congressionally mandated 2017 report by the National Academies of Sciences, Engineering, and Medicine, which identified a need for enhanced transparency, greater scientific rigor, and updates to the scientific methodology for the DGA process. This paper traces the history of these ideas and contextualizes the DGA within the law and regulations that govern its process. The paper also discusses how recent iterations of the Dietary Guidelines have not fully adhered to these guiding documents, which has resulted in diminished independence of the expert committee in charge of evaluating the science for the DGA and a continued lack of a fully rigorous scientific process for producing consistent and trustworthy guidelines for the public.
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Affiliation(s)
- Cheryl Achterberg
- Department of Human Science, The Ohio State University, Columbus, OH, USA
| | - Arne Astrup
- Healthy Weight Center, Novo Nordisk Foundation, Hellerup, Denmark
| | - Dennis M Bier
- Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA
| | - Janet C King
- Department of Nutritional Sciences and Toxicology, University of California-Berkeley, Berkeley, CA, USA
| | - Ronald M Krauss
- Department of Pediatrics, University of California-San Francisco, San Francisco, CA, USA
- Department of Medicine, University of California-San Francisco, San Francisco, CA, USA
| | | | - Jeff S Volek
- Department of Human Science, The Ohio State University, Columbus, OH, USA
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3
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Astrup A, Teicholz N, Magkos F, Bier DM, Brenna JT, King JC, Mente A, Ordovas JM, Volek JS, Yusuf S, Krauss RM. Dietary Saturated Fats and Health: Are the U.S. Guidelines Evidence-Based? Nutrients 2021; 13:3305. [PMID: 34684304 PMCID: PMC8541481 DOI: 10.3390/nu13103305] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/08/2021] [Accepted: 09/16/2021] [Indexed: 11/16/2022] Open
Abstract
The last decade has seen nearly 20 papers reviewing the totality of the data on saturated fats and cardiovascular outcomes, which, altogether, have demonstrated a lack of rigorous evidence to support continued recommendations either to limit the consumption of saturated fatty acids or to replace them with polyunsaturated fatty acids. These papers were unfortunately not considered by the process leading to the most recent U.S. Dietary Guidelines for Americans, the country's national nutrition policy, which recently reconfirmed its recommendation to limit saturated fats to 10% or less of total energy intake, based on insufficient and inconsistent evidence. Continuation of a cap on saturated fat intake also fails to consider the important effects of the food matrix and the overall dietary pattern in which saturated fatty acids are consumed.
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Affiliation(s)
- Arne Astrup
- Healthy Weight Center, Novo Nordisk Foundation, Tuborg Havnevej 19, 2900 Hellerup, Denmark
| | | | - Faidon Magkos
- Department of Nutrition, Exercise and Sports, University of Copenhagen, 1958 Frederiksberg C, Denmark;
| | - Dennis M. Bier
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA;
| | - J. Thomas Brenna
- Department of Pediatrics, Dell Pediatric Research Institute, University of Texas at Austin, Austin, TX 78723, USA;
- Department of Chemistry, Dell Pediatric Research Institute, University of Texas at Austin, Austin, TX 78723, USA
- Department of Nutrition, Dell Pediatric Research Institute, University of Texas at Austin, Austin, TX 78723, USA
| | - Janet C. King
- Department of Nutritional Sciences and Toxicology, University of California-Berkeley, Berkeley, CA 94720, USA;
| | - Andrew Mente
- Population Health Research Institute, Hamilton Health Sciences, Hamilton, ON L8L 2X2, Canada; (A.M.); (S.Y.)
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - José M. Ordovas
- Nutrition and Genomics Laboratory, Human Nutrition Research Center of Aging, Tufts University, Boston, MA 02111, USA;
- IMDEA Food Institute, 28049 Madrid, Spain
| | - Jeff S. Volek
- Department of Human Sciences, Ohio State University, Columbus, OH 43210, USA;
| | - Salim Yusuf
- Population Health Research Institute, Hamilton Health Sciences, Hamilton, ON L8L 2X2, Canada; (A.M.); (S.Y.)
- Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Ronald M. Krauss
- Department of Pediatrics, University of California-San Francisco, San Francisco, CA 94609, USA;
- Department of Medicine, University of California-San Francisco, San Francisco, CA 94609, USA
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4
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Bier DM. Dietary Sugars: Not as Sour as They Are Made Out to Be. Nestle Nutr Inst Workshop Ser 2020; 95:100-111. [PMID: 33166963 DOI: 10.1159/000511524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 06/22/2020] [Indexed: 01/22/2023]
Abstract
Over the course of evolution, Mother Nature preserved the ability of humans to make every sugar they need for metabolic functions. Glucose is the almost exclusive fuel preferred by the human brain. Human infants are born with sweet taste receptors, sugars are a significant energy source in human milk, and mammals have a direct gut-to-brain sugar-sensing system that enhances development of a preference for sugars. If sugars are as toxic as many postulate, what species advantage was conferred by this evolutionary progression? Observational studies have reported that sugar consumption is associated with various adverse health risks. However, observational studies can never prove causality, dietary intake records are known to be highly problematic, and the huge number of correlation interdependencies among environmental "exposome" variables makes it impossible to attribute causality to individual dietary components. Additionally, these studies overall have been graded as low quality, and many reported the small effect sizes are likely within the propagated methodological "noise." With several exceptions, data from randomized controlled trials that ensured isocaloric energy intakes have failed to confirm the causal implications of the observational data. Likewise, the comprehensive UK Scientific Committee on Nutrition Report on Carbohydrates and Health also failed to confirm the vast majority of widely postulated detrimental effects of sugar consumption per se. Current data on intakes of sugar-sweetened beverages and on the risks associated with high intakes of dietary fructose remain under debate.
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Affiliation(s)
- Dennis M Bier
- Department of Pediatrics, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA,
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5
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Cynober L, Bier DM, Stover P, Kadowaki M, Morris SM, Elango R, Smriga M. Proposals for Upper Limits of Safe Intake for Methionine, Histidine, and Lysine in Healthy Humans. J Nutr 2020; 150:2606S-2608S. [PMID: 33000163 DOI: 10.1093/jn/nxaa231] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 06/15/2020] [Accepted: 07/10/2020] [Indexed: 12/21/2022] Open
Abstract
Based on research presented during the 10th Amino Acid Assessment Workshop, no observed adverse effect levels (NOAELs) for supplemental methionine at 46 mg/(kg·d) (∼3.2 g/d), for supplemental histidine at 8.0 g/d, and for supplemental lysine at 6.0 g/d have been proposed. These NOAELs are relevant to healthy adults and are applicable only to high-purity amino acids administered in fortified foods or dietary supplements. Because individuals are exposed to the above supplemental amino acids in the context of complex combinations of essential amino acids or individually in dietary supplements for various physiologic benefits, such as body fat reduction, skin conditioning, mental energy increase, or herpes simplex treatments, the above safety recommendations will make an important contribution to regulatory and nutritional practices.
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Affiliation(s)
- Luc Cynober
- Scientific Advisory Committee of the International Council for Amino Acid Science (ICAAS), Brussels, Belgium.,Clinical Chemistry Laboratory, Cochin Hospital, AP-HP, Paris, France.,Biological Nutrition Laboratory and EA 4466, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - Dennis M Bier
- Scientific Advisory Committee of the International Council for Amino Acid Science (ICAAS), Brussels, Belgium.,USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA
| | - Patrick Stover
- Scientific Advisory Committee of the International Council for Amino Acid Science (ICAAS), Brussels, Belgium.,Texas A&M AgriLife, College Station, TX, USA
| | - Motoni Kadowaki
- Scientific Advisory Committee of the International Council for Amino Acid Science (ICAAS), Brussels, Belgium.,Department of Engineering, Niigata Institute of Technology, Niigata, Japan
| | - Sidney M Morris
- Scientific Advisory Committee of the International Council for Amino Acid Science (ICAAS), Brussels, Belgium.,University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA
| | - Rajavel Elango
- Scientific Advisory Committee of the International Council for Amino Acid Science (ICAAS), Brussels, Belgium.,Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
| | - Miro Smriga
- International Council for Amino Acid Science (ICAAS), Brussels, Belgium
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6
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Brown AW, Kaiser KA, Keitt A, Fontaine K, Gibson M, Gower BA, Shikany JM, Vorland CJ, Beitz DC, Bier DM, Brenna JT, Jacobs DR, Kris-Etherton P, Maki K, Miller M, St-Onge MP, Teran-Garcia M, Allison DB. Science dialogue mapping of knowledge and knowledge gaps related to the effects of dairy intake on human cardiovascular health and disease. Crit Rev Food Sci Nutr 2020; 61:179-195. [PMID: 32072820 DOI: 10.1080/10408398.2020.1722941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dairy has been described as everything from a superfood to a poison; yet, arguments, assumptions, and data justifying these labels are not always clear. We used an issue-based information system, "dialogue mapping™," to summarize scientific points of a live panel discussion on the putative effects of dairy on cardiovascular diseases (CVD) from a day-long session among experts in nutrition and CVD. Dialogue mapping captures relations among ideas to explicitly, logically, and visually connect issues/questions, ideas, pro/con arguments, and agreements, even if discussed at different times. Experts discussed two propositions: for CVD risk, consumption of full-fat dairy products 1) should be minimized, in part because of their saturated fat content, or 2) need not be minimized, despite their saturated fat content. The panel discussed the dairy-CVD relation through blood lipids, diabetes, obesity, energy balance, blood pressure, dairy bioactives, biobehavioral components, and other putative causal pathways. Associations and effects reported in the literature have varied by fat content of dairy elements considered, study design, intake methods, and biomarker versus disease outcomes. Two conceptual topics emerged from the discussion: 1) individual variability: whether recommendations should be targeted only to those at high CVD risk; 2) quality of evidence: whether data on dairy-CVD relations are strong enough for reliable conclusions-positive, negative, or null. Future procedural improvements for science dialog mapping include using singular rather than competing propositions for discussion.
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Affiliation(s)
- Andrew W Brown
- Department of Applied Health Science, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, USA
| | - Kathryn A Kaiser
- Department of Health Behavior, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Andrew Keitt
- Department of History, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kevin Fontaine
- Department of Health Behavior, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Madeline Gibson
- School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Barbara A Gower
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - James M Shikany
- Division of Preventive Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Colby J Vorland
- Department of Applied Health Science, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, USA
| | - Donald C Beitz
- Departments of Animal Science and Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Dennis M Bier
- Baylor College of Medicine, Department of Pediatrics, Children's Nutrition Research Center, Houston, Texas, USA
| | - J Thomas Brenna
- Dell Pediatric Research Institute, Deptartments of Pediatrics, of Chemistry, and of Nutrition, University of Texas at Austin, Austin, Texas, USA
| | - David R Jacobs
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Penny Kris-Etherton
- Distinguished Professor of Nutrition, Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kevin Maki
- Department of Applied Health Science, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, USA.,Midwest Biomedical Research/Center for Metabolic and Cardiovascular Health, Addison, Illinois, USA
| | - Michael Miller
- Epidemiology & Public Health, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Marie-Pierre St-Onge
- Division of Endocrinology and Sleep center of excellence, Department of Medicine, Columbia University Irving Medical Center, New York, New York, USA
| | - Margarita Teran-Garcia
- Extension Specialist Hispanic Health Programs, Department of Human Development and Family Studies, Cooperative Extension, Division of Nutritional Sciences, Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - David B Allison
- Department of Epidemiology and Biostatistics, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, USA
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7
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Astrup A, Bier DM. A view from the "new world". Eur J Clin Nutr 2018; 72:1198-1199. [PMID: 30185864 DOI: 10.1038/s41430-018-0232-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 05/17/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Arne Astrup
- Faculty of Science Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg C, Denmark.
| | - Dennis M Bier
- Baylor College of Medicine, Children's Nutrition Research Center, Houston, TX, USA
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8
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Abstract
Nearly 50 years ago, I set out to investigate the clinical problem of hypoglycemia in children with illnesses that limited their food intake. My goal was to gather accurate and precise measurable data. At the time, I wasn't interested in nutrition as a discipline defined in its more general or popular sense. To address the specific problem that interested me required development of entirely new methods based on stable, nonradioactive tracers that satisfied the conditions of accuracy and precision. At the time, I had no inclination of the various theoretical and practical problems that would have to be solved to achieve this goal. Some are briefly described here. Nor did I have the slightest idea that developing the field would result in a fundamental change in how human clinical investigation was conducted, with the eventual replacement of radiotracers with stable isotopically labeled ones, even for adult clinical investigation. Additionally, I had no inclination that the original questions would open avenues to much broader questions of practical nutritional relevance. Moreover, only much later as the editor of The American Journal of Clinical Nutrition did I appreciate the policy implications of how nutritional data are presented in the scientific literature. At least in part, less accurate and precise measurements and less than full transparency in reporting nutritional data have resulted in widespread debate about the public policy recommendations and guidelines that are the intended result of collecting the data in the first place. This article provides a personal recollection (with all the known faults of self-reporting and retrospective memory) of the journey that starts with measurement certainty and ends with policy uncertainty.
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Affiliation(s)
- Dennis M Bier
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030;
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9
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Magni P, Bier DM, Pecorelli S, Agostoni C, Astrup A, Brighenti F, Cook R, Folco E, Fontana L, Gibson RA, Guerra R, Guyatt GH, Ioannidis JPA, Jackson AS, Klurfeld DM, Makrides M, Mathioudakis B, Monaco A, Patel CJ, Racagni G, Schünemann HJ, Shamir R, Zmora N, Peracino A. Perspective: Improving Nutritional Guidelines for Sustainable Health Policies: Current Status and Perspectives. Adv Nutr 2017; 8:532-545. [PMID: 28710141 PMCID: PMC5502870 DOI: 10.3945/an.116.014738] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A large body of evidence supports the notion that incorrect or insufficient nutrition contributes to disease development. A pivotal goal is thus to understand what exactly is appropriate and what is inappropriate in food ingestion and the consequent nutritional status and health. The effective application of these concepts requires the translation of scientific information into practical approaches that have a tangible and measurable impact at both individual and population levels. The agenda for the future is expected to support available methodology in nutrition research to personalize guideline recommendations, properly grading the quality of the available evidence, promoting adherence to the well-established evidence hierarchy in nutrition, and enhancing strategies for appropriate vetting and transparent reporting that will solidify the recommendations for health promotion. The final goal is to build a constructive coalition among scientists, policy makers, and communication professionals for sustainable health and nutritional policies. Currently, a strong rationale and available data support a personalized dietary approach according to personal variables, including sex and age, circulating metabolic biomarkers, food quality and intake frequency, lifestyle variables such as physical activity, and environmental variables including one's microbiome profile. There is a strong and urgent need to develop a successful commitment among all the stakeholders to define novel and sustainable approaches toward the management of the health value of nutrition at individual and population levels. Moving forward requires adherence to well-established principles of evidence evaluation as well as identification of effective tools to obtain better quality evidence. Much remains to be done in the near future.
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Affiliation(s)
- Paolo Magni
- Department of Pharmacological and Biomolecular Sciences, and
| | - Dennis M Bier
- Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX
| | | | - Carlo Agostoni
- Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, DISCCO, Università degli Studi di Milano, Milan, Italy
| | - Arne Astrup
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Furio Brighenti
- Department of Food Sciences, University of Parma, Parma, Italy
| | - Robert Cook
- Bazian, Economist Intelligence Unit Healthcare, London, United Kingdom
| | - Emanuela Folco
- Giovanni Lorenzini Medical Science Foundation, Milan, Italy
| | - Luigi Fontana
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy;,Department of Medicine, Washington University, St. Louis, MO
| | - Robert A Gibson
- School of Agriculture, Food and Wine, FOODplus Research Centre, University of Adelaide, Adelaide, Australia
| | - Ranieri Guerra
- Department of Preventive Health, Ministry of Health, Rome, Italy
| | - Gordon H Guyatt
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
| | - John PA Ioannidis
- Department of Health Policy and Research, Stanford University, Stanford, CA
| | - Ann S Jackson
- Giovanni Lorenzini Medical Science Foundation, Houston, TX
| | - David M Klurfeld
- Human Nutrition Program, USDA Agricultural Research Service, Beltsville, MD
| | - Maria Makrides
- Healthy Mothers, Babies and Children, South Australian Health and Medical Research Institute, Adelaide, Australia
| | | | | | - Chirag J Patel
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA
| | - Giorgio Racagni
- Department of Pharmacological and Biomolecular Sciences, and
| | - Holger J Schünemann
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
| | - Raanan Shamir
- Institute of Gastroenterology, Nutrition and Liver Diseases, Schneider Children’s Medical Center of Israel, Sackler Faculty of Medicine, University of Tel Aviv, Tel Aviv, Israel; and
| | - Niv Zmora
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Andrea Peracino
- Giovanni Lorenzini Medical Science Foundation, Milan, Italy;
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10
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Yetley EA, MacFarlane AJ, Greene-Finestone LS, Garza C, Ard JD, Atkinson SA, Bier DM, Carriquiry AL, Harlan WR, Hattis D, King JC, Krewski D, O'Connor DL, Prentice RL, Rodricks JV, Wells GA. Options for basing Dietary Reference Intakes (DRIs) on chronic disease endpoints: report from a joint US-/Canadian-sponsored working group. Am J Clin Nutr 2017; 105:249S-285S. [PMID: 27927637 PMCID: PMC5183726 DOI: 10.3945/ajcn.116.139097] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Dietary Reference Intakes (DRIs) are used in Canada and the United States in planning and assessing diets of apparently healthy individuals and population groups. The approaches used to establish DRIs on the basis of classical nutrient deficiencies and/or toxicities have worked well. However, it has proved to be more challenging to base DRI values on chronic disease endpoints; deviations from the traditional framework were often required, and in some cases, DRI values were not established for intakes that affected chronic disease outcomes despite evidence that supported a relation. The increasing proportions of elderly citizens, the growing prevalence of chronic diseases, and the persistently high prevalence of overweight and obesity, which predispose to chronic disease, highlight the importance of understanding the impact of nutrition on chronic disease prevention and control. A multidisciplinary working group sponsored by the Canadian and US government DRI steering committees met from November 2014 to April 2016 to identify options for addressing key scientific challenges encountered in the use of chronic disease endpoints to establish reference values. The working group focused on 3 key questions: 1) What are the important evidentiary challenges for selecting and using chronic disease endpoints in future DRI reviews, 2) what intake-response models can future DRI committees consider when using chronic disease endpoints, and 3) what are the arguments for and against continuing to include chronic disease endpoints in future DRI reviews? This report outlines the range of options identified by the working group for answering these key questions, as well as the strengths and weaknesses of each option.
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Affiliation(s)
| | | | | | - Cutberto Garza
- Boston College, Chestnut Hill, MA
- Department of Global Health, George Washington University Milken Institute School of Public Health, Washington, DC
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Jamy D Ard
- Wake Forest School of Medicine, Wake Forest University, Winston-Salem, NC
| | | | - Dennis M Bier
- Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX
| | | | | | - Dale Hattis
- The George Perkins Marsh Institute, Clark University, Worcester, MA
| | - Janet C King
- Children's Hospital Oakland Research Institute, Oakland, CA
- Department of Nutritional Sciences, University of California, Berkeley, Berkeley, CA
- Department of Nutrition, University of California, Davis, Davis, CA
| | - Daniel Krewski
- McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Ontario, Canada
| | - Deborah L O'Connor
- Department of Nutritional Sciences, University of Toronto
- The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ross L Prentice
- Fred Hutchinson Cancer Research Center
- School of Public Health, University of Washington, Seattle, WA
| | | | - George A Wells
- Department of Epidemiology and Community Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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11
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Cynober L, Bier DM, Kadowaki M, Morris SM, Elango R, Smriga M. Proposals for Upper Limits of Safe Intake for Arginine and Tryptophan in Young Adults and an Upper Limit of Safe Intake for Leucine in the Elderly. J Nutr 2016; 146:2652S-2654S. [PMID: 27934658 DOI: 10.3945/jn.115.228478] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 01/08/2016] [Accepted: 04/29/2016] [Indexed: 11/14/2022] Open
Abstract
On the basis of research presented during the 9th Amino Acid Assessment Workshop, a No Observed Adverse Effect Level (NOAEL) for diet-added arginine (added mostly in the form of dietary supplements) of 30 g/d and an upper limit of safe intake (ULSI) for diet-added tryptophan (added mostly in the form of dietary supplements) of 4.5 g/d have been proposed. Both recommendations apply to healthy young adults. The total dietary leucine ULSI proposed for elderly individuals is 500 mg · kg-1 · d-1 All 3 recommendations are relevant only to high-quality amino acid-containing products with specifications corresponding to those listed in the US Pharmacopeia Because the above amino acids are extensively utilized as dietary supplements for various real or perceived benefits, such as vasodilation, spermatogenesis, sleep, mood regulation, or muscle recovery, the above safety recommendations will have an important impact on regulatory and nutritional practices.
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Affiliation(s)
- Luc Cynober
- Clinical Chemistry Laboratory, Cochin Hospital, AP-HP, Paris, France; .,Biological Nutrition Laboratory and.,EA 4466, Faculty of Pharmacy, Paris Descartes University, Paris, France.,Scientific Advisory Committee of the International Council on Amino Acid Science
| | - Dennis M Bier
- USDA Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX.,Scientific Advisory Committee of the International Council on Amino Acid Science
| | - Motoni Kadowaki
- Graduate School of Science and Technology, Niigata University, Niigata, Japan.,Scientific Advisory Committee of the International Council on Amino Acid Science
| | - Sidney M Morris
- University of Pittsburgh School of Medicine, Pittsburgh, PA.,Scientific Advisory Committee of the International Council on Amino Acid Science
| | - Rajavel Elango
- Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; and.,Scientific Advisory Committee of the International Council on Amino Acid Science
| | - Miro Smriga
- International Council on Amino Acid Science, Brussels, Belgium
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12
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Affiliation(s)
- Dennis M Bier
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX; and
| | - Walter C Willett
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA
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13
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Bier DM, Allison DB, Alpers DH, Astrup A, Cashman KD, Coates PM, Fukagawa NK, Klurfeld DM, Mattes RD, Uauy R. Introduction to the series "Best (but Oft-Forgotten) Practices". Am J Clin Nutr 2015; 102:239-40. [PMID: 26178729 DOI: 10.3945/ajcn.115.117697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Dennis M Bier
- USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX;
| | - David B Allison
- School of Public Health, University of Alabama at Birmingham, Birmingham, AL
| | | | - Arne Astrup
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Kevin D Cashman
- School of Food and Nutritional Sciences, University College Cork, Cork, Ireland
| | | | | | - David M Klurfeld
- Office of National Programs, USDA Agricultural Research Service, Beltsville, MD
| | - Richard D Mattes
- Department of Foods and Nutrition, Purdue University, West Lafayette, IN; and
| | - Ricardo Uauy
- London School of Hygiene and Tropical Medicine, London, United Kingdom
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15
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Abstract
Humans interact with food daily. Such repeated exposure creates a widespread, superficial familiarity with nutrition. Personal familiarity with nutrition from individual and cultural perspectives may give rise to beliefs about food not grounded in scientific evidence. In this summary of the session entitled “Unscientific Beliefs about Scientific Topics in Nutrition,” we discuss accumulated work illustrating and quantifying potentially misleading practices in the conduct and, more so, reporting of nutrition science along with proposed approaches to amelioration. We begin by defining “unscientific beliefs” and from where such beliefs may come, followed by discussing how large bodies of nutritional epidemiologic observations not only create highly improbable patterns of association but implausible magnitudes of implied effect. Poor reporting practices, biases, and methodologic issues that have distorted scientific understandings of nutrition are presented, followed by potential influences of conflicts of interest that extend beyond financial considerations. We conclude with recommendations for improving the conduct, reporting, and communication of nutrition-related research to ground discussions in evidence rather than solely on beliefs.
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Affiliation(s)
- Andrew W. Brown
- Office of Energetics and Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL,To whom correspondence should be addressed. E-mail:
| | - John P. A. Ioannidis
- Stanford Prevention Research Center, Stanford University School of Medicine, Palo Alto, CA
| | | | - Dennis M. Bier
- USDA/Agricultural Research Service, Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX
| | - David B. Allison
- Office of Energetics and Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL
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16
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Abstract
The real and important role of epidemiology was discussed, noting heretofore unknown associations that led to improved understanding of the cause and prevention of individual nutritional deficiencies. However, epidemiology has been less successful in linking individual nutrients to the cause of chronic diseases, such as cancer and cardiovascular disease. Dietary changes, such as decreasing caloric intake to prevent cancer and the Mediterranean diet to prevent diabetes, were confirmed as successful approaches to modifying the incidence of chronic diseases. The role of the epidemiologist was confirmed as a collaborator, not an isolated expert of last resort. The challenge for the future is to decide which epidemiologic methods and study designs are most useful in studying chronic disease, then to determine which associations and the hypotheses derived from them are especially strong and worthy of pursuit, and finally to design randomized studies that are feasible, affordable, and likely to result in confirmation or refutation of these hypotheses.
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Affiliation(s)
- David H. Alpers
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO,To whom correspondence should be addressed. E-mail:
| | - Dennis M. Bier
- USDA/Agricultural Research Service Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX
| | - Kenneth J. Carpenter
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA
| | - Donald B. McCormick
- Department of Biochemistry and Graduate Program in Nutrition and Health Sciences, Emory University, Atlanta, GA
| | - Anthony B. Miller
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada; and
| | - Paul F. Jacques
- USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA
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17
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Kimura T, Bier DM, Taylor CL. Summary of workshop discussions on establishing upper limits for amino acids with specific attention to available data for the essential amino acids leucine and tryptophan. J Nutr 2012; 142:2245S-2248S. [PMID: 23077196 DOI: 10.3945/jn.112.160846] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The morning of the first day of the 8th Amino Acid Assessment Workshop was organized and co-sponsored by the International Council on Amino Acid Science (ICAAS) and the International Life Sciences Institute Research Foundation and was focused on the International Life Sciences Institute Research Foundation's approach to establishing upper limits of nutrients. The remainder of d 1 and all of d 2 were focused on the safety of leucine and tryptophan, with special emphasis on determining the upper level of the safe range of intake. It was recognized that some toxicological frameworks, mainly the key-events dose response framework, might be applicable to amino acids and provide appropriate assistance to regulators in establishing upper limits for amino acids as a group of nutrients used in dietary supplements. ICAAS-funded projects for determining the upper intake limits for the essential amino acid leucine provided the main pool of leucine data discussed at the workshop. The acute clinical study suggests 500 mg/(kg · d) as a possible upper limit for leucine in healthy humans, but the safety margin needed to widen this limit to the general population has not been determined. For tryptophan, the workshop participants found less ground for consensus. Older efficacy studies suggested that tryptophan at 8-15 g/d was well tolerated, but human research was abruptly terminated in the late 1980s and no new data are available. Animal results obtained in pigs and rodents were discussed and 2 possible strategies for applying those outcomes to humans were described.
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Abstract
Based on recent research, an upper limit of safe intake (ULSI) for leucine is proposed for healthy adults: 0.53 g/(kg·d). Because leucine has been used as a dietary supplement for many years in people practicing exercise and sport, further study with long-term exposure to leucine in this specific subpopulation should be performed to eventually adjust the ULSI.
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Affiliation(s)
- Luc Cynober
- Clinical Chemistry Laboratory, Cochin and Hôtel-Dieu Hospitals, AP-HP, Paris, France.
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Bier DM. Promoting innovation in pediatric nutrition. Nestle Nutr Workshop Ser Pediatr Program 2010; 66:205-215. [PMID: 20664227 DOI: 10.1159/000318959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Truly impactful innovation can only be recognized in retrospect. Moreover, almost by definition, developing algorithmic paths on roadmaps for innovation are likely to be unsuccessful because innovators do not generally follow established routes. Nonetheless, environments can be established within Departments of Pediatrics that promote innovating thinking. The environmental factors necessary to do so include: (1) demand that academic Pediatrics Departments function in an aggressively scholarly mode; (2) capture the most fundamental science in postnatal developmental biology; (3) focus education and training on the boundaries of our knowledge, rather than the almost exclusive attention to what we think we already know; (4) devote mentoring, time and resources to only the most compelling unanswered questions in the pediatric sciences, including nutrition; (5) accept only systematic, evidence-based answers to clinical questions; (6) if systematic, evidence-based data are not available, design the proper studies to get them; (7) prize questioning the answers to further move beyond the knowledge limit; (8) support the principle that experiments in children will be required to convincingly answer clinical questions important to children, and (9) establish the multicenter resources in pediatric scientist training, clinical study design and implementation, and laboratory and instrument technologies required to answer today's questions with tomorrow's methods.
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Affiliation(s)
- Dennis M Bier
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA
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21
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Abstract
Given the increase in the incidence of insulin resistance, obesity, and type 2 diabetes in children and adolescents, it would be of paramount importance to assess quantitative indices of insulin secretion and action during a physiological perturbation, such as a meal or an oral glucose-tolerance test (OGTT). A minimal model method is proposed to measure quantitative indices of insulin secretion and action in adolescents from an oral test. A 7 h, 21-sample OGTT was performed in 11 adolescents. The C-peptide minimal model was identified on C-peptide and glucose data to quantify indices of beta-cell function: static phi(s) and dynamic phi(d) responsivity to glucose from which total responsivity phi was also measured. The glucose minimal model was identified on glucose and insulin data to estimate insulin sensitivity, S(I), which was compared to a reference measure, S(I)(ref), provided by a tracer method. Disposition indices, which adjust insulin secretion for insulin action, were then calculated. Indices of beta-cell function were phi(s) = 51.35 +/- 8.89 x 10(-9)min(-1), phi(d) = 1,392 +/- 258 x 10(-9), and phi = 82.09 +/- 17.70 x 10(-9)min(-1). Insulin sensitivity was S(I) = 14.19 +/- 2.73 x 10(-4), not significantly different from S(I)(ref) = 14.96 +/- 3.04 x 10(-4) dl/kg.min per microU/ml, and well correlated: r = 0.98, P < 0.0001, thus indicating that S(I) can be accurately measured from an oral test. Disposition indices were DI(s) = 1,040 +/- 201 x 10(-14) dl/kg/min(2) per pmol/l, DI(d) = 33,178 +/- 10,720 x 10(-14) dl/kg/min per pmol/l, DI = 1,844 +/- 522 x 10(-14) dl/kg/min(2) per pmol/l. Virtually the same minimal model assessment was obtained with a reduced 3 h, 9-sample protocol. OGTT interpreted with C-peptide and glucose minimal model has the potential to provide novel insight regarding the regulation of glucose metabolism in adolescents, and to evaluate the effect of obesity and interventions such as diet and exercise.
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Affiliation(s)
- Agneta L Sunehag
- Children Nutrition's Research Center, Baylor College of Medicine, Houston, Texas, USA
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22
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Abstract
The prevention and treatment of childhood obesity have proven to be extremely difficult problems. Since the equation for maintaining energy balance is an extremely simple one, having only two terms, 'energy in' and 'energy out', the difficulties encountered in its application for obesity management are not immediately obvious. Among the problems that make practical application of the energy balance equation more difficult than expected are: (1) the precise feedback control system that is designed to maintain weight within a given range; (2) the aggressive resistance of the system to attempts to exceed its boundaries; (3) inaccurate assessment of energy intake in practice; (4) the dominant role of genes in determining body weight; (5) the polygenic nature of obesity and the fact that any single gene accounts for a small fraction of the genetic variation in weight; (6) underestimation of the genetic contribution to the current 'epidemic' of obesity; (7) the fact that 'modifiable' risk factors may be less modifiable than expected; (8) appreciation that family role modeling may be less influential than anticipated, and (9) the realization that our knowledge about the development of physical activity behaviors in childhood is extremely limited.
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Affiliation(s)
- Dennis M Bier
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA
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23
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Abstract
Birth and adaptation to extrauterine life involve major shifts in the protein and energy metabolism of the human newborn. These include a shift from a state of continuous supply of nutrients including amino acids from the mother to cyclic periodic oral intake, a change in the redox state of organs, thermogenesis, and a significant change in the mobilization and use of oxidative substrates. The development of safe, stable isotopic tracer methods has allowed the study of protein and amino acid metabolism not only in the healthy newborn but also in those born prematurely and of low birth weight. These studies have identified the unique and quantitative aspects of amino acid/protein metabolism in the neonate, thus contributing to rational nutritional care of these babies. The present review summarizes the contemporary data on some of the significant developments in essential and dispensable amino acids and their relationship to overall protein metabolism. Specifically, the recent data of kinetics of leucine, phenylalanine, glutamine, sulfur amino acid, and threonine and their relation to whole-body protein turnover are presented. Finally, the physiological rationale and the impact of nutrient (amino acids) interventions on the dynamics of protein metabolism are discussed.
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Affiliation(s)
- Satish C Kalhan
- Department of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195, USA.
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Sunehag AL, Toffolo G, Campioni M, Bier DM, Haymond MW. Short-term high dietary fructose intake had no effects on insulin sensitivity and secretion or glucose and lipid metabolism in healthy, obese adolescents. J Pediatr Endocrinol Metab 2008; 21:225-35. [PMID: 18540249 DOI: 10.1515/jpem.2008.21.3.225] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
UNLABELLED There is virtually no information on the metabolic impact of dietary fructose intake in adolescents despite their high fructose consumption, particularly via sweetened beverages. AIM To determine the short-term metabolic effects of dietary fructose intake in obese adolescents. METHODS Six volunteers (3 M/3 F; 15.2 +/- 0.5 yr; 35 +/- 2 kg/m2; 39 +/- 2% body fat) were studied twice following 7 d of isocaloric, isonitrogenous high carbohydrate (60% CHO; 25% fat) diets with fructose accounting for 6% and 24% of total energy intake, respectively (random order). Insulin sensitivity and secretion were analyzed by the stable labeled intravenous glucose tolerance test and glucose and lipid kinetics using GCMS. RESULTS A fourfold increase in dietary fructose intake did not affect insulin sensitivity or secretion, glucose kinetics, lipolysis or glucose, insulin, C-peptide, triglycerides, HDL- and LDL-cholesterol concentrations. CONCLUSIONS In the short term, when energy intake is constant, dietary fructose per se is not a contributor to insulin resistance and hypersecretion in obese adolescents.
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Affiliation(s)
- Agneta L Sunehag
- Baylor College of Medicine, Children's Nutrition Research Center, Houston, TX 77030, USA.
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25
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Bier DM, Abrams SA, Bowman BA, Fukagawa NK, Gitlin JD, Klurfeld DM, Sacks FM. Conflict of interest policy for Editors of The American Journal of Clinical Nutrition. Am J Clin Nutr 2007; 86:3-4. [PMID: 17616755 DOI: 10.1093/ajcn/86.1.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Mullis RM, Blair SN, Aronne LJ, Bier DM, Denke MA, Dietz W, Donato KA, Drewnowski A, French SA, Howard BV, Robinson TN, Swinburn B, Wechsler H. Prevention Conference VII: Obesity, a worldwide epidemic related to heart disease and stroke: Group IV: prevention/treatment. Circulation 2005; 110:e484-8. [PMID: 15520333 DOI: 10.1161/01.cir.0000140072.49273.6b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Sunehag AL, Toffolo G, Campioni M, Bier DM, Haymond MW. Effects of dietary macronutrient intake on insulin sensitivity and secretion and glucose and lipid metabolism in healthy, obese adolescents. J Clin Endocrinol Metab 2005; 90:4496-502. [PMID: 15928240 DOI: 10.1210/jc.2005-0626] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Adolescent obesity is a serious public health concern. OBJECTIVE The aim of the study was to determine whether obese adolescents can adapt metabolically to changes in dietary macronutrient intake. PATIENTS AND DESIGN Using a random cross-over design, 13 healthy obese volunteers (six boys and seven girls; age, 14.7 +/- 0.3 yr; body mass index, 34 +/- 1 kg/m2; body fat, 42 +/- 1%) were studied twice after 7 d of isocaloric, isonitrogenous diets with 60% carbohydrate (CHO) and 25% fat (high CHO), or 30% CHO and 55% fat (low CHO). MAIN OUTCOME MEASURES AND METHODS Glucose metabolism, insulin sensitivity, and first- and second-phase insulin secretory indices were measured by stable isotope techniques and the stable labeled iv glucose tolerance test. The results were compared with those of previously studied lean adolescents. RESULTS Obese adolescents increased first- and second-phase insulin secretory indices by 18 (P = 0.05) and 36% (P = 0.05), respectively, to maintain normoglycemia during the high-CHO diet because they failed to increase insulin sensitivity as did the lean adolescents. Regardless of diet, in obese adolescents, insulin sensitivity was half (P < 0.05) and first- and second-phase insulin secretory indices twice (P < 0.01), compared with the the corresponding values in lean subjects. In obese adolescents, gluconeogenesis increased by 32% during the low-CHO (high-fat diet) (P < 0.01). CONCLUSION In obese adolescents, insulin secretory demands were increased regardless of diet. Failure to increase insulin sensitivity while receiving a high-CHO diet required a further increase in insulin secretion, which may lead to earlier beta-cell failure. A low-CHO/high-fat diet resulted in increased gluconeogenesis, which may be a prelude to the increased glucose production and hyperglycemia observed in type 2 diabetics.
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Affiliation(s)
- Agneta L Sunehag
- Baylor College of Medicine, Children's Nutrition Research Center, 1100 Bates Street, Houston, Texas 77030, USA.
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Zeisel SH, Freake HC, Bauman DE, Bier DM, Burrin DG, German JB, Klein S, Marquis GS, Milner JA, Pelto GH, Rasmussen KM. The nutritional phenotype in the age of metabolomics. J Nutr 2005; 135:1613-6. [PMID: 15987837 PMCID: PMC2430109 DOI: 10.1093/jn/135.7.1613] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The concept of the nutritional phenotype is proposed as a defined and integrated set of genetic, proteomic, metabolomic, functional, and behavioral factors that, when measured, form the basis for assessment of human nutritional status. The nutritional phenotype integrates the effects of diet on disease/wellness and is the quantitative indication of the paths by which genes and environment exert their effects on health. Advances in technology and in fundamental biological knowledge make it possible to define and measure the nutritional phenotype accurately in a cross section of individuals with various states of health and disease. This growing base of data and knowledge could serve as a resource for all scientific disciplines involved in human health. Nutritional sciences should be a prime mover in making key decisions that include: what environmental inputs (in addition to diet) are needed; what genes/proteins/metabolites should be measured; what end-point phenotypes should be included; and what informatics tools are available to ask nutritionally relevant questions. Nutrition should be the major discipline establishing how the elements of the nutritional phenotype vary as a function of diet. Nutritional sciences should also be instrumental in linking the elements that are responsive to diet with the functional outcomes in organisms that derive from them. As the first step in this initiative, a prioritized list of genomic, proteomic, and metabolomic as well as functional and behavioral measures that defines a practically useful subset of the nutritional phenotype for use in clinical and epidemiological investigations must be developed. From this list, analytic platforms must then be identified that are capable of delivering highly quantitative data on these endpoints. This conceptualization of a nutritional phenotype provides a concrete form and substance to the recognized future of nutritional sciences as a field addressing diet, integrated metabolism, and health.
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Affiliation(s)
- S H Zeisel
- American Society for Nutritional Sciences Long Range Planning Committee, Bethesda, MD 20814-3990, USA.
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Abstract
Tracer kinetic studies of amino acid metabolism during periods of high amino acid intake should allow insights into adaptive or maladaptive regulatory mechanisms controlling amino acid catabolic or disposal events before clinically evident effects. The principles of amino acid tracer kinetics have been well defined, but their application to establishing upper safe intake levels has been essentially nonexistent. Similarly, the pharmacology field has well-established disciplines of toxicokinetics (the relationship of toxicant dose and delivery to its site of action) and toxicodynamics (the relationship of toxicant at its site of action and downstream functional consequences), but these principles have not been transferred to the field of amino acid metabolism. In this context, a theoretical framework is presented for tracer kinetic experiments to help establish upper tolerable levels of amino acid infusion and/or ingestion. In addition, experiments to couple specific amino acid intake levels with their consequent physiological dynamic effects are suggested to lead to the construction of benefit-risk curves that may permit definition of safe amino acid intake ranges for the population.
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Affiliation(s)
- Dennis M Bier
- Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030, USA.
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Treuth MS, Sunehag AL, Trautwein LM, Bier DM, Haymond MW, Butte NF. Metabolic adaptation to high-fat and high-carbohydrate diets in children and adolescents. Am J Clin Nutr 2003; 77:479-89. [PMID: 12540411 DOI: 10.1093/ajcn/77.2.479] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Difficulty adapting to high-fat (HF) and high carbohydrate (HC) diets may predispose children to obesity and diabetes. OBJECTIVE We tested the hypothesis that children have metabolic flexibility to adapt to HF and HC diets. DESIGN In protocol 1, 12 children aged 6-9 y and 12 adolescents aged 13-16 y were randomly assigned in a crossover design to consume low-fat (LF), HC (25% and 60% of energy, respectively) or HF, low-carbohydrate (LC) (55% and 30% of energy, respectively) diets. In protocol 2, 12 adolescents aged 13-16 y were randomly assigned in a crossover design to consume an LF-HC diet with 11% or 40% of carbohydrate as fructose. Total energy expenditure, nonprotein respiratory quotients (NPRQs), and substrate utilization were measured by using 24-h calorimetry. Effects of sex, puberty, body fat (dual-energy X-ray absorptiometry), intraabdominal fat (magnetic resonance imaging), and fitness on substrate utilization were tested. RESULTS Substrate utilization was not affected by puberty, body fat, intraabdominal fat, or fitness. Total energy expenditure was not affected by diet. In protocol 1, NPRQs and carbohydrate and fat utilization were significantly affected by diet (P = 0.001) and sex (P = 0.005). NPRQs and carbohydrate utilization increased with the LF-HC diet. NPRQs decreased and fat utilization increased with the HF-LC diet; changes in substrate utilization were less pronounced in females than in males. In protocol 2, 24-h NPRQs and 24-h substrate utilization were not significantly affected by fructose, although net carbohydrate and fat utilization were significantly lower and higher, respectively, with the high-fructose diet during fasting (P = 0.01) and in the subsequent feeding period (P = 0.05). CONCLUSION Healthy, nonobese children and adolescents adapt appropriately to HF and HC diets.
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Affiliation(s)
- Margarita S Treuth
- US Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston 77030, USA
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Sunehag AL, Toffolo G, Treuth MS, Butte NF, Cobelli C, Bier DM, Haymond MW. Effects of dietary macronutrient content on glucose metabolism in children. J Clin Endocrinol Metab 2002; 87:5168-78. [PMID: 12414888 DOI: 10.1210/jc.2002-020674] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Effects of carbohydrate, fat, and fructose intake on substrate and hormone concentrations, glucose production, gluconeogenesis, and insulin sensitivity were determined in healthy, nonobese prepubertal children (n = 12) and adolescents (n = 24) using a cross-over design. In one group (12 prepubertal children and 12 adolescents), subjects were studied after 7 d of isocaloric, isonitrogenous diets providing either 60% carbohydrate and 25% fat [high carbohydrate (H(CHO))/low fat (L(F))] or 30% carbohydrate and 55% fat [low carbohydrate (L(CHO))/high fat (H(F))], and in a second group (12 adolescents) H(CHO)/L(F) diets containing either 40% or 10% fructose was used. All subjects adapted to changes in carbohydrate and fat intakes primarily by appropriately adjusting their substrate oxidation rates to match the intakes, with only minor changes in parameters of glucose metabolism. Changing from a L(CHO)/H(F) to H(CHO)/L(F) diet resulted in increased insulin sensitivity (stable labeled iv glucose tolerance test) in adolescents [from 3.2 +/- 0.7 x 10(-4) to 5.0 +/- 1.4 x 10(-4) (min(-1))/( micro U.ml(-1)) (mean +/- SE)] but not in prepubertal children [9.4 +/- 2.5 x 10(-4) to 9.9 +/- 1.5 x 10(-4) (min(-1))/( micro U.ml(-1))], whereas beta-cell sensitivity was unaffected in both groups. Insulin sensitivity was higher in prepubertal children than in adolescents (P < 0.05). The dietary fructose content did not affect any measured parameter. We conclude that in the short term, dramatic changes in fat and carbohydrate intakes (regardless of fructose content) did not adversely affect glucose and lipid metabolism in healthy nonobese children. In the adolescents, the high carbohydrate diet resulted in increased insulin sensitivity, thus facilitating insulin-mediated glucose uptake.
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Affiliation(s)
- Agneta L Sunehag
- Children's Nutrition Research Center, USDA Agricultural Research Service, 1100 Bates Street, Houston, TX 77030, USA.
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Miller TL, Easley KA, Zhang W, Orav EJ, Bier DM, Luder E, Ting A, Shearer WT, Vargas JH, Lipshultz SE. Maternal and infant factors associated with failure to thrive in children with vertically transmitted human immunodeficiency virus-1 infection: the prospective, P2C2 human immunodeficiency virus multicenter study. Pediatrics 2001; 108:1287-96. [PMID: 11731650 PMCID: PMC4383837 DOI: 10.1542/peds.108.6.1287] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE Many children with human immunodeficiency virus-1 (HIV-1) have chronic problems with growth and nutrition, yet limited information is available to identify infected children at high risk for growth abnormalities. Using data from the prospective, multicenter P2C2 HIV study, we evaluated the relationships between maternal and infant clinical and laboratory factors and impaired growth in this cohort. METHODS Children of HIV-1-infected women were enrolled prenatally or within the first 28 days of life. Failure to thrive (FTT) was defined as an age- and sex-adjusted weight z score < or =-2.0 SD. Maternal baseline covariates included age, race, illicit drug use, zidovudine use, CD4+ T-cell count, and smoking. Infant baseline predictors included sex, race, CD4+ T-cell count, Centers for Disease Control stage, HIV-1 RNA, antiretroviral therapy, pneumonia, heart rate, cytomegalovirus, and Epstein-Barr virus infection status. RESULTS The study cohort included 92 HIV-1-infected and 439 uninfected children. Infected children had a lower mean gestational age, but birth weights, lengths, and head circumferences in the 2 groups were similar. Mothers of growth-delayed infants were more likely to have smoked tobacco and used illicit drugs during pregnancy. In repeated-measures analyses of weight and length or height z scores, the means of the HIV-1-infected group were significantly lower at 6 months of age (P <.001) and remained lower throughout the first 5 years of life. In a multivariable Cox regression analysis, FTT was associated with a history of pneumonia (relative risk [RR] = 8.78; 95% confidence interval [CI]: 3.59-21.44), maternal use of cocaine, crack, or heroin during pregnancy (RR = 3.17; 95% CI: 1.51-6.66), infant CD4+ T-cell count z score (RR = 2.13 per 1 SD decrease; 95% CI: 1.25-3.57), and any antiretroviral therapy by 3 months of age (RR = 2.77; 95% CI: 1.16-6.65). After adjustment for pneumonia and antiretroviral therapy, HIV-1 RNA load remained associated with FTT in the subset of children whose serum was available for viral load analysis. CONCLUSIONS Clinical and laboratory factors associated with FTT among HIV-1-infected children include history of pneumonia, maternal illicit drug use during pregnancy, lower infant CD4+ T-cell count, exposure to antiretroviral therapy by 3 months of age (non-protease inhibitor), and HIV-1 RNA viral load.
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Affiliation(s)
- T L Miller
- Division of Pediatric Gastroenterology and Nutrition, University of Rochester Medical Center, NY 14642, USA.
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Sunehag AL, Treuth MS, Toffolo G, Butte NF, Cobelli C, Bier DM, Haymond MW. Glucose production, gluconeogenesis, and insulin sensitivity in children and adolescents: an evaluation of their reproducibility. Pediatr Res 2001; 50:115-23. [PMID: 11420428 DOI: 10.1203/00006450-200107000-00021] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The prevalence of overweight and obese children has doubled, and the incidence of type 2 diabetes in children (0-19 y) has increased 4-fold during the past several decades. As a result we can anticipate an increased number of metabolic studies in children. There are few data on measures of glucose metabolism in normal children, and virtually none relating to their reproducibility. The aims of this study were 1) to provide new data on energy expenditure and glucose, lipid, and protein metabolism in nonobese, healthy children and adolescents; 2) to evaluate their reproducibility; and 3) on the basis of these data, to perform power calculations for metabolic studies. Eight nonobese subjects (8-16 y) were studied on two occasions, preceded by 7 d of a diet with identical energy content and macronutrient distribution. Gluconeogenesis, measured by deuterium oxide, accounted for 50% of glucose production. Insulin sensitivity, measured by the labeled minimal model, averaged 4.9 x 10(-4) mL(mU x min)(-1). Glucose appearance rate was significantly higher (p < 0.01) in the children than in the adolescents. Furthermore, we demonstrated that for energy intake and expenditure, plasma concentrations of glucose and C-peptide, and rates of appearance of glucose and leucine, a 10% difference can be detected in fewer than five subjects with a power of 80% and a type I error of 5%. Insulin concentration, gluconeogenesis, insulin secretory indices, insulin sensitivity, and glucose effectiveness were more variable, but with the above power a difference of 25% could be detected in 7-11 subjects using a paired study design.
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Affiliation(s)
- A L Sunehag
- Children's Nutrition Research Center, Houston, Texas 77030, USA.
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36
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Affiliation(s)
- Dennis M Bier
- From the Department of Pediatrics, Baylor College of Medicine, Houston; the University of Iowa Hospitals and Clinics, Iowa City; and the University of Turku, Finland
| | - Ronald M Lauer
- From the Department of Pediatrics, Baylor College of Medicine, Houston; the University of Iowa Hospitals and Clinics, Iowa City; and the University of Turku, Finland
| | - Olli Simell
- From the Department of Pediatrics, Baylor College of Medicine, Houston; the University of Iowa Hospitals and Clinics, Iowa City; and the University of Turku, Finland
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Bier DM, Lauer RM, Simell O. Fat intake during childhood. Summary. Am J Clin Nutr 2000; 72:1410S-1413S. [PMID: 11063486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Affiliation(s)
- D M Bier
- Department of Pediatrics, Baylor College of Medicine, Houston
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38
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Bier DM, Lauer RM, Simell O. Preface. Am J Clin Nutr 2000. [DOI: 10.1093/ajcn/72.5.1245s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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39
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Caumo A, Vicini P, Zachwieja JJ, Avogaro A, Yarasheski K, Bier DM, Cobelli C. Undermodeling affects minimal model indexes: insights from a two-compartment model. Am J Physiol 1999; 276:E1171-93. [PMID: 10362630 DOI: 10.1152/ajpendo.1999.276.6.e1171] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The classic (hereafter cold) and the labeled (hereafter hot) minimal models are powerful tools to investigate glucose metabolism. The cold model provides, from intravenous glucose tolerance test (IVGTT) data, indexes of glucose effectiveness (SG) and insulin sensitivity (SI) that measure the effect of glucose and insulin, respectively, to enhance glucose disappearance and inhibit endogenous glucose production. The hot model provides, from hot IVGTT data, indexes of glucose effectiveness (SG*) and insulin sensitivity (SI*) that, respectively, measure the effects of glucose and insulin on glucose disappearance only. Recent reports call for a reexamination of some of the assumptions of the minimal models. We have previously pointed out the criticality of the single-compartment description of glucose kinetics on which both the minimal models are founded. In this paper we evaluate the impact of single-compartment undermodeling on SG, SI*, and by using a two-compartment model to describe the glucose system. The relationships of the minimal model indexes to the analogous indexes measured with the glucose clamp technique are also examined. Theoretical analysis and simulation studies indicate that cold indexes are more affected than hot indexes by undermodeling. In particular, care must be exercised in the physiological interpretation of SG, because this index is a local descriptor of events taking place in the initial portion of the IVGTT. As a consequence, SG not only reflects glucose effect on glucose uptake and production but also the rapid exchange of glucose between the accessible and nonaccessible glucose pools that occurs in the early part of the test.
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Affiliation(s)
- A Caumo
- San Raffaele Scientific Institute, 20100 Milan, Italy
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40
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Abstract
Very low birth weight (VLBW) infants are dependent on total parenteral nutrition (TPN) to prevent hypoglycemia and provide a sufficient energy intake. However, diminished tolerance for parenteral glucose delivered at high rates frequently provokes hyperglycemia. We hypothesized that when their glucose supply is reduced to prevent hyperglycemia, VLBW infants can maintain normoglycemia via gluconeogenesis from glycerol and amino acids. Twenty infants born at 27 +/- 0.2 (mean +/- SE) gestational weeks and having a birth weight of 996 +/- 28 g, received lipids (1.6 +/- 0.1 mg x kg(-1) x min(-1)), protein (2.2 +/- 0.1 mg x kg(-1) x min(-1)), and glucose (3.1 +/- 0.1 mg x kg(-1) x min(-1) [17.1 +/- 0.2 micromol x kg(-1) x min(-1)]) parenterally over a period of 8-12 h on day 5.0 +/- 0.2 of life. Gluconeogenesis was estimated using [U-13C]glucose (n = 8) or [2-(13)C] glycerol (n = 6) and mass isotopomer distribution analysis (MIDA), or 2H2O (n = 6) and the rate of deuterium incorporation in carbon 6 of glucose. Blood glucose averaged 3.0 +/- 0.1 mmol/l; plasma glucose appearance rate (glucose Ra), 28.8 +/- 1.1 micromol x kg(-1) x min(-1); and glucose production rate (GPR), 10.7 +/- 1.0 micromol x kg(-1) x min(-1). The [U-13C]glucose and [2-(13)C]glycerol tracers provided similar estimates of gluconeogenesis, averaging 28 +/- 2 and 26 +/- 2% of glucose Ra and 72 +/- 5 and 73 +/- 9% of GPR, respectively. Glycerol contributed 64 +/- 5% of total gluconeogenesis. Gluconeogenesis measured by 2H2O, which does not include the contribution from glycerol, was comparable to the nonglycerol fraction of gluconeogenesis derived by the [2-(13)C]glycerol MIDA. We conclude that in VLBW infants receiving TPN, normoglycemia was maintained during reduced glucose infusion by glucose production primarily derived from gluconeogenesis, and that glycerol was the principal gluconeogenic substrate.
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Affiliation(s)
- A L Sunehag
- US Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA.
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41
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Bier DM, Brosnan JT, Flatt JP, Hanson RW, Heird W, Hellerstein MK, Jéquier E, Kalhan S, Koletzko B, Macdonald I, Owen O, Uauy R. Report of the IDECG Working Group on lower and upper limits of carbohydrate and fat intake. International Dietary Energy Consultative Group. Eur J Clin Nutr 1999; 53 Suppl 1:S177-8. [PMID: 10365996 DOI: 10.1038/sj.ejcn.1600759] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- D M Bier
- Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA
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42
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Vicini P, Zachwieja JJ, Yarasheski KE, Bier DM, Caumo A, Cobelli C. Glucose production during an IVGTT by deconvolution: validation with the tracer-to-tracee clamp technique. Am J Physiol 1999; 276:E285-94. [PMID: 9950788 DOI: 10.1152/ajpendo.1999.276.2.e285] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recently, a new method, based on a two-compartment minimal model and deconvolution [A. Caumo and C. Cobelli. Am. J. Physiol 264 (Endocrinol. Metab. 37): E829-E841, 1993; P. Vicini, G. Sparacino, A. Caumo, and C. Cobelli. Comput. Meth. Prog. Biomed. 52: 147-156, 1997], has been proposed to estimate endogenous glucose production (EGP) from labeled intravenous glucose tolerance test (IVGTT) data. Our aim here is to compare this EGP profile with that independently obtained with the reference method, based on the tracer-to-tracee ratio (TTR) clamp. An insulin-modified (0.03 U/kg body wt infused over 5 min) [6,6-2H2]glucose-labeled IVGTT (0.33 g/kg of glucose) was performed in 10 normal subjects. A second tracer ([U-13C]glucose) was also infused during the test in a variable fashion to clamp endogenous glucose TTR. The TTR clamp was quite successful. As a result, the EGP profile, reconstructed from [U-13C]glucose data with the models of Steele and Radziuk, were almost superimposable. The deconvolution-obtained EGP profile, calculated from [6,6-2H2]glucose data, showed remarkable agreement with that obtained from the TTR clamp. Some differences between the two profiles were noted in the estimated basal EGP and in the initial modalities of EGP inhibition. A high interindividual variability was also observed with both methods in the resumption of EGP to baseline; variability was high in both the timing and the extent of resumption. In conclusion, the use of the two-compartment minimal model of the IVGTT and deconvolution allows the estimation of a profile of EGP that is in very good agreement with that independently obtained with a TTR clamp.
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Affiliation(s)
- P Vicini
- Department of Electronics and Informatics, University of Padova, 35131 Padova, Italy
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Abstract
In order to follow the movement and quantify the metabolic fates of biologically important molecules in vivo, both tracers and kinetic modeling are required. For the study of intermediary metabolism in children, stable isotopically labeled substrates satisfy both the analytical and ethical requirements for tracer use in children. Stable isotope tracers have been proven safe over more than a half-century of use in humans. In addition, mass spectrometric analysis of stable nuclide molecular position and isotopic enrichment in biological molecules is both highly specific and extraordinarily precise. Using stable isotope data to develop models of biological system dynamics in vivo is an essential element of estimating substrate events that take place in cells or organs otherwise inaccessible for ethical sampling in children. Further, modeling is also a critical component in the development and the testing of hypotheses about the structure of the biological system in question and the mechanisms which control its operational parameters.
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Affiliation(s)
- D M Bier
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
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Perriello G, Nurjhan N, Stumvoll M, Bucci A, Welle S, Dailey G, Bier DM, Toft I, Jenssen TG, Gerich JE. Regulation of gluconeogenesis by glutamine in normal postabsorptive humans. Am J Physiol 1997; 272:E437-45. [PMID: 9124550 DOI: 10.1152/ajpendo.1997.272.3.e437] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
There is evidence that glutamine may act as a regulator of protein, free fatty acid, and glycogen metabolism. To test the hypothesis that glutamine may act as a physiological regulator of gluconeogenesis, we infused 16 normal postabsorptive volunteers with glutamine at a rate (11.4 micromol kg(-1) x min(-1)) estimated to approximate its appearance in plasma after a protein meal and assessed changes in production of glucose from glutamine, systemic glucose appearance and disposal, and uptake and release of glucose, glutamine, and alanine by forearm skeletal muscle. Although infusion of glutamine increased plasma glutamine concentration and turnover only threefold (from 0.63 +/- 0.03 to 1.95 +/- 0.10 mmol/l and from 5.43 +/- 0.24 to 14.85 +/- 0.66 micromol x kg(-1) x min(-1), respectively; P < 0.001), formation of glucose from glutamine increased sevenfold from 0.55 +/- 0.03 to 3.74 +/- 0.28 micromol x kg(-1) x min(-1) (P < 0.001). Formation of glucose from alanine was also stimulated (0.52 +/- 0.05 vs. 0.75 +/- 0.04 micromol x kg(-1) x min(-1); P < 0.001) in the absence of a change in plasma alanine concentration. Furthermore, glutamine infusion decreased its own de novo synthesis (4.55 +/- 0.22 vs. 2.81 +/- 0.62 micromol x kg(-1) x min(-1);P < 0.02) while increasing that of alanine (2.82 +/- 0.32 vs. 3.56 +/- 0.32 micromol x kg(-1) x min(-1); P < 0.002). Systemic glucose appearance, systemic glucose disposal, and forearm balance of glucose and alanine were not altered. Because the stimulatory effects of glutamine on gluconeogenesis occurred in the absence of changes in plasma insulin and glucagon levels, these results provide evidence that, in humans, glutamine may act both as a substrate and as a regulator of gluconeogenesis as well as a modulator of its own metabolism.
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Affiliation(s)
- G Perriello
- The University of Rochester School of Medicine, New York 14642, USA
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45
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Abstract
The purpose of this study was to determine whether GH treatment of cystic fibrosis (CF) patients can result in an anabolic effect, i.e., increased weight gain, improved growth rate, nitrogen retention, and improved pulmonary function. Nine prepubertal endocrinologically normal CF patients (3 girls, 6 boys; chronological age (CA) 5.5-9.8 years, and bone age (BA) 4.5-9.0 years), received recombinant human growth hormone (rhGH) 0.3 mg/kg/week subcutaneously for a period of 12 months (N = 8) or 9 months (N = 1). Normal glucose tolerance was determined before treatment. Pulmonary function studies and anthropometric measurements were done every 3 months. Thyroid status, somatomedin C (SmC), BA, and routine chemistries were evaluated every 6 months. The pretreatment growth velocity averaged 5.7 +/- 0.3 (SE) cm/year and significantly increased to 7.8 +/- 0.4 (SE) cm/year during therapy, (P < 0.01). Standard deviation scores (SDS) for height significantly increased during rhGH therapy as compared with pretreatment, (P < 0.05). Weight of the patients during rhGH therapy did not significantly change during or after rhGH therapy. After therapy, all patients showed a significant increase in arm muscle area (AMA) and a significant decrement in arm fat area (AFA) (P < 0.01). Net nitrogen anabolism was negative in all subjects before therapy but became more positive in five patients during rhGH therapy. Three patients achieved positive nitrogen retention. SmC values significantly increased from a mean value of 0.62 +/- 0.1 (SE) U/ml to 1.6 +/- 0.6 (SE) U/ml after therapy. BA advanced 1.0 +/- 0.1 SE per year after treatment. Of the seven patients able to perform adequate pulmonary function testing, improvement occurred in FVC, FEV1.0, and PEFR in 5, 5, and 4 patients, respectively, but these changes did not reach statistical significance. We conclude that biosynthetic rhGH therapy had a significant anabolic effect in CF patients as shown by increased growth velocity, SmC values, increased protein and decreased fet stores, and a positive or less negative net nitrogen retention in five of the patients.
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Affiliation(s)
- C A Huseman
- Department of Pediatrics, University of Nebraska Medical School, Omaha 68198-5180, USA
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46
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Zachwieja JJ, Toffolo G, Cobelli C, Bier DM, Yarasheski KE. Resistance exercise and growth hormone administration in older men: effects on insulin sensitivity and secretion during a stable-label intravenous glucose tolerance test. Metabolism 1996; 45:254-60. [PMID: 8596499 DOI: 10.1016/s0026-0495(96)90063-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To assess the effects of 16 weeks of heavy resistance exercise training (RE) on insulin sensitivity and secretion in healthy older men aged 64 to 75 years (N = 15), stable-label ([6,6,2H2]glucose) intravenous glucose tolerance tests (IVGTTs) were performed before and 7 days after the last bout of exercise. Glucose disappearance rate (Rd) and an index of insulin sensitivity (Si*) were derived using the minimal model of labeled glucose disappearance, and insulin secretion parameters were derived from C-peptide and glucose concentrations measured during the IVGTT, using a minimal model of C-peptide secretion and kinetics. Each subject trained at an intensity of 70% to 95% maximum strength 4 d/wk for 16 weeks on Nautilus (DeLand, FL) weight-training equipment. In conjunction with exercise, six men received daily injections of recombinant human growth hormone ([rhGH] 12.5 to 24 microg/kg/d) and the other nine received placebo injections. GH/placebo injections were administered in a double-blind randomized fashion. The RE program was supervised and progressive in nature, consisting of both upper-and lower-body exercises, and significantly increased muscle strength (P < .05) with no additional benefit from rhGH except for a tendency toward a greater increase in fat-free mass (FFM) in the RE + GH group (P = .06). Peak glucose Rd increased following RE (P < 01), and there was a trend for an improved Si* (ie, from 6.79 +/- 1.14 to 8.42 +/- 0.89 x 10(4) per min/[microU/mL], P = .06). Peak glucose Rd and Si* were unchanged in the RE + GH group following treatment. First- and second-phase insulin secretion were not affected by RE or RE + GH. Glucose tolerance, quantified as the glucose disappearance constant (Kg) between 10 and 32 minutes of the IVGTT, was unchanged by exercise or hormone treatment. These findings support those of a recent study that used the hyperinsulinemic-euglycemic clamp technique (Miller et al, J Appl Physiol 77:1122-1127, 1994), and suggest that when healthy older men engage in RE, whole-body glucose Rd and Si* are improved, and these beneficial effects are not only due to the acute effects of the last bout of exercise. Additionally, in six subjects who received GH, glucose Rd and Si* were not significantly improved following the RE program. Although this may suggest that GH can diminish improvements in glucose Rd and Si* that result from RE, further study is needed to confirm this observation.
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Affiliation(s)
- J J Zachwieja
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge 70808, USA
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47
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Saccomani MP, Bonadonna RC, Bier DM, DeFronzo RA, Cobelli C. A model to measure insulin effects on glucose transport and phosphorylation in muscle: a three-tracer study. Am J Physiol 1996; 270:E170-85. [PMID: 8772490 DOI: 10.1152/ajpendo.1996.270.1.e170] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We studied five healthy subjects with perfused forearm and euglycemic clamp techniques in combination with a three-tracer (D-[12C]mannitol, not transportable; 3-O-[14C]methyl-D-glucose, transportable but not metabolizable; D-[3-3H]glucose, transportable and metabolizable) intra-arterial pulse injection to assess transmembrane transport and intracellular phosphorylation of glucose in vivo in human muscle. The washout curves of the three tracers were analyzed with a multicompartmental model. A priori identifiability analysis of the tracer model shows that the rate constants of glucose transport into and out of the cells and of glucose phosphorylation are uniquely identifiable. Tracer model parameters were estimated by a nonlinear least-squares parameter estimation technique. We then solved for the tracee model and estimated bidirectional transmembrane transport glucose fluxes, glucose intracellular phosphorylation, extracellular and intracellular volumes of glucose distribution, and extracellular and intracellular glucose concentrations. Physiological hyperinsulinemia (473 +/- 22 pM) caused 2.7-fold (63.1 +/- 7.2 vs. 23.4 +/- 6.1 mumol.min-1.kg-1, P < 0.01) and 5.1-fold (42.5 +/- 5.8 vs. 8.4 +/- 2.2 mumol.min-1.kg-1, P < 0.01) increases in transmembrane influx and intracellular phosphorylation of glucose, respectively. Extracellular distribution volume and concentration of glucose were unchanged, whereas intracellular distribution volume of glucose was increased (approximately 2-fold) and intracellular glucose concentration was almost halved by hyperinsulinemia. In summary, 1) a multicompartment model of three-tracer kinetic data can quantify transmembrane glucose fluxes and intracellular glucose phosphorylation in human muscle; and 2) physiological hyperinsulinemia stimulates both transport and phosphorylation of glucose and, in doing so, amplifies the role of glucose transport as a rate-determining step of muscle glucose uptake.
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Affiliation(s)
- M P Saccomani
- Department of Electronics and Informatics, University of Padua, Italy
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48
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Vlachopapadopoulou E, Zachwieja JJ, Gertner JM, Manzione D, Bier DM, Matthews DE, Slonim AE. Metabolic and clinical response to recombinant human insulin-like growth factor I in myotonic dystrophy--a clinical research center study. J Clin Endocrinol Metab 1995; 80:3715-23. [PMID: 8530624 DOI: 10.1210/jcem.80.12.8530624] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Muscle weakness and wasting in myotonic dystrophy (MyD) are believed to be due to a decrease in muscle protein synthesis, secondary to insulin resistance. A 4-month, randomized, double blind, placebo-controlled trial was undertaken to assess whether recombinant human insulin-like growth factor I (rhIGF-I) may overcome the insulin resistance. Patients received either 5 mg rhIGF-I (n = 7) or placebo (n = 9), sc, twice daily. Glucose metabolism was assessed by stable label iv glucose tolerance test, amino acid metabolism by L-[13C] leucine turnover, body composition by dual energy x-ray absorptiometry and N excretion, and muscle response by manual muscle strength and neuromuscular function. In the treated group, the insulin sensitivity index, insulin action, and glucose disposal all increased (P < 0.05). Leucine flux and leucine incorporation into protein increased (P < 0.05), and the rate of leucine oxidation to leucine turnover decreased (P < 0.05), findings indicative of increased protein synthesis. Body weight and lean body mass increased, whereas percent body fat decreased (P < 0.05). An increase in manual muscle strength of 0.42 +/- 0.30 (P < 0.02) and in neuromuscular function of 17.5 +/- 11.7 (P < 0.02) occurred in the four patients who received a rhIGF-I dose greater than 70 micrograms/kg, whereas a more modest response occurred in the three patients who received a dose less than 70 micrograms/kg. Two patients showed dramatic improvement. Long term rhIGF-I therapy appears to cause metabolic and muscle improvement in optimally treated MyD patients.
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Affiliation(s)
- E Vlachopapadopoulou
- Department of Pediatrics, New York Hospital-Cornell Medical Center, New York 10021, USA
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49
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Arends J, Schäfer G, Schauder P, Bircher J, Bier DM. Comparison of serine and hippurate as precursor equivalents during infusion of [15N]glycine for measurement of fractional synthetic rates of apolipoprotein B of very-low-density lipoprotein. Metabolism 1995; 44:1253-8. [PMID: 7476280 DOI: 10.1016/0026-0495(95)90025-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Enrichment in hippurate has been measured to indicate precursor enrichment during glycine tracer infusion studies to estimate fractional synthetic rates of individual hepatic export proteins. However, hippurate tends to overestimate precursor enrichment. Since glycine is rapidly converted to serine by liver cells, we compared tracer enrichment in hippurate and serine with that of glycine incorporated into apolipoprotein (apo) B-100. Ten healthy control subjects were studied in the postabsorptive state during an 8-hour primed-constant infusion of [15N]glycine (10 mumol.kg-1.h-1). Apo B of very-low-density lipoprotein (VLDL) was isolated by standard ultracentrifugation and isopropanol precipitation. Glycine and serine were isolated from plasma and hydrolyzed apo B, hippurate was isolated from plasma, and [15N]enrichment was determined by gas chromatography-mass spectrometry. Enrichment in serine and glycine isolated from apo B was identical at all time points, and their enrichment in apo B increased asymptotically, approaching an apparent plateau (mean +/- SD: 91% +/- 10% of calculated plateau at 8 hours) that was taken to represent hepatic protein precursor enrichment. Enrichment in both plasma serine and hippurate followed a biphasic pattern and continued to increase until the end of the study, raising the possibility that precursor enrichment had not reached a steady state during the study. The apo B plateau was lower (factor 0.76 +/- 0.27) than the final enrichment in hippurate and higher (factor 1.38 +/- 0.36) than that in plasma serine; however, predictions of protein precursor enrichment based on either metabolite were flawed by a large coefficient of variation (35% v 26%).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Arends
- Department of Internal Medicine, University of Göttingen, Germany
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50
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Perriello G, Jorde R, Nurjhan N, Stumvoll M, Dailey G, Jenssen T, Bier DM, Gerich JE. Estimation of glucose-alanine-lactate-glutamine cycles in postabsorptive humans: role of skeletal muscle. Am J Physiol 1995; 269:E443-50. [PMID: 7573421 DOI: 10.1152/ajpendo.1995.269.3.e443] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To evaluate transfer of carbon between plasma glucose and plasma alanine (glucose-alanine cycle) and lactate (Cori cycle), to assess the contribution of skeletal muscle to these cycles, and to determine whether a glucose-glutamine cycle exists in postabsorptive humans, we infused 11 normal overnight-fasted volunteers with [2-3H]glucose, [6-14C]glucose, and [3-13C]alanine to isotopic steady state and in 7 of these simultaneously measured forearm net balance, uptake, and release of labeled and unlabeled glucose, lactate, and alanine. We found that 40.9 +/- 3.3, 66.8 +/- 3.2, and 13.4 +/- 1.1%, respectively, of plasma alanine, lactate, and glutamine carbon came from plasma glucose. More plasma glucose was converted to plasma alanine than could be derived from plasma alanine (1.89 +/- 0.20 vs. 1.48 +/- 0.15 mumol.kg-1.min-1, P < 0.001). A similar direction of net carbon flux was found for lactate (8.5 vs. 4.2 mumol.kg-1.min-1), with only glutamine adding more carbon to plasma glucose than was received from it (1.0 vs. 0.75 mumol.kg-1.min-1). Skeletal muscle accounted for 50.2 +/- 3.9 and 45.5 +/- 5.7% of the overall appearance of alanine and lactate in plasma and 54.2 +/- 5.4 and 36.4 +/- 4.2% of their respective origins from plasma glucose. Skeletal muscle release of alanine and lactate that had been formed from plasma glucose accounted for 19.1 +/- 2.1 and 48.4 +/- 4.8%, respectively, of muscle glucose uptake and 42.4 +/- 5.5 and 49.9 +/- 5.8% of the overall release of alanine and lactate from muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- G Perriello
- Division of Endocrinology and Metabolism, Scripps Clinic, La Jolla, California 92037, USA
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