HARMONIZATION
OF
APPROACHES
TO
NUTRIENT
REFERENCE VALUES
APPLICATIONS TO YOUNG CHILDREN AND
WOMEN OF REPRODUCTIVE AGE
Committee on the Application of Global Harmonization of
Methodological Approaches to Nutrient Intake Recommendations for
Young Children and Women of Reproductive Age
Food and Nutrition Board
Health and Medicine Division
A Consensus Study Report of
THE NATIONAL ACADEMIES PRESS
Washington, DC
www.nap.edu
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This activity was supported by a contract between the National Academy of Sciences and the Bill & Melinda Gates Foundation (Grant OPP1150751) and by the Kellogg Endowment Fund of the National Academy of Sciences’ Health and Medicine Division. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any organization or agency that provided support for the project.
International Standard Book Number-13: 978-0-309-47769-7
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Digital Object Identifier: https://doi.org/10.17226/25148
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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2018. Harmonization of approaches to nutrient reference values: Applications to young children and women of reproductive age. Washington, DC: The National Academies Press. doi: https://doi.org/10.17226/25148.
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COMMITTEE ON THE APPLICATION OF GLOBAL HARMONIZATION OF METHODOLOGICAL APPROACHES TO NUTRIENT INTAKE RECOMMENDATIONS FOR YOUNG CHILDREN AND WOMEN OF REPRODUCTIVE AGE
ROBERT E. BLACK (Chair), Edgar Berman Professor, Director, Institute for International Programs, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
LINDSAY ALLEN, Center Director, Agricultural Research Center, Western Human Nutrition Research Center, U.S. Department of Agriculture, Davis, California
ZULFIQAR A. BHUTTA, Noordin Noormahomed Sheriif Endowed Professor and Founding Chair, Division of Women and Child Health, Aga Khan University, Toronto, Ontario
SUSAN FAIRWEATHER-TAIT, Professor, Human Nutrition, Norwich Medical School, University of East Anglia, Norwich, United Kingdom
WAFAIE FAWZI, Richard Saltonstall Professor of Population Sciences, Professor of Nutrition, Epidemiology, and Global Health, Chair, Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
MARY L’ABBÉ, Earle W. McHenry Professor, Chair, Department of Nutritional Sciences, University of Toronto, Ontario, Canada
LAURA MARTINO, Senior Statistician, Systematic Review and Experimental Design Team, Assessment and Methodological Support Unit, European Food Safety Authority, Parma, Italy
HILDEGARD PRZYREMBEL, Professor, Director, Federal Institute for Risk Assessment, Berlin, Germany
EMORN UDOMKESMALEE, Senior Advisor, Institute of Nutrition, Mahidol University, Nakhon Pathom Province, Thailand
Study Staff
GILLIAN BUCKLEY, Study Director
AMANDA NGUYEN, Associate Program Officer
MEREDITH YOUNG, Senior Program Assistant
ANN L. YAKTINE, Director, Food and Nutrition Board
Consultants
JANET KING, Professor Emeritus, University of California, Berkeley, and Davis; Senior Scientist, Children’s Hospital Oakland Research Institute, Oakland, California
LESLIE PRAY, Science Writer
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Reviewers
This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.
We thank the following individuals for their review of this report:
STEPHANIE A. ATKINSON, McMaster University
PATSY M. BRANNON, Cornell University
KATHRYN G. DEWEY, University of California, Davis
SUSAN KREBS-SMITH, National Cancer Institute, National Institutes of Health
JOSEPH LAU, Brown University School of Public Health
AMANDA MacFARLANE, Health Canada
SUZANNE P. MURPHY, Emerita, University of Hawaii at Manoa
PATRICK J. STOVER, Texas A&M University System
Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations of this report nor did they see the final draft before its release. The review of this report was overseen by M. R. C. GREENWOOD,
University of California, Davis, and Santa Cruz, and SUSAN C. SCRIMSHAW, Tufts University. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.
Preface
The establishment of reference values for nutrient intakes of populations is essential for making recommendations for appropriate, safe dietary intakes and for designing nutritional interventions, such as nutrient fortification of foods. Traditionally these efforts have been directed at preventing nutrient deficiencies. Additionally, with the increasing globalization of information and identification of factors that influence the specific nutritional needs of different population groups (e.g., young children and women of reproductive age), there has been a growing appreciation for the need to develop nutrient reference values that are applicable across countries and that take into account the varying needs of different population subgroups.
In recognition of this expanding range of concerns regarding the nutritional needs of populations, the United Kingdom and the United States, in the 1990s, convened a group of experts who proposed a new approach to setting nutrient intake recommendations to address these concerns. The outcome of those efforts was the development of new methodologies for setting nutrient intake values that were adopted initially in the United States in collaboration with Canada and in the United Kingdom. Similar approaches were developed and adopted by many European and other middle- and high-income countries. In spite of these advances, the methods are challenging for countries to apply, and there has been limited guidance on when and how to adapt the values from high-income countries for use in more resource-constrained countries. While the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) have published nutrient reference values with some consideration of diverse dietary and environmental conditions, these recommendations have not been updated
regularly and have not employed recent advances in methods for synthesis and analysis of evidence.
In 2009, the Department of Nutrition for Health and Development of WHO established a new process and approach for developing and updating nutrition guidelines, and in 2010 a WHO Nutrition Guidance Expert Advisory Group (NUGAG) was formed to strengthen the role of WHO in providing science-based advice, evidence-informed policy, and program guidance in support of the WHO Nutrition Program. Simultaneously, the Global Network of Institutions for Scientific Advice on Nutrition was formed to provide scientific advice on nutrition and to establish nutrition recommendations and guidelines. The Global Network met in Geneva, Switzerland, in 2010 to share information about nutrition guidance and explore opportunities for collaboration as a step toward harmonization of diet- and nutrition-related recommendations and guidelines. An important outcome of the meeting was recognition of the need to synergize efforts and examine approaches for developing nutrition guidance, including the harmonization of methods for (1) assessing the evidence underpinning nutrition science and (2) developing nutrient intake recommendations and guidance to steer national policy development.
Today there is greater consistency across high-income countries in the methodological approach used to derive an average nutrient requirement (AR) and safe upper intake level (UL), the two fundamental values needed for establishing nutrient intake recommendations. However, there remains considerable inconsistency across other national and international bodies, particularly in low- and middle-income countries, in the approaches used to derive nutrient intake recommendations for their populations. Moreover, there are no consistent processes in place to ensure that any such intake recommendations remain current and relevant to those population subgroups.
With these activities as a backdrop, the Bill & Melinda Gates Foundation recognized the need for action toward developing a uniform and consistent basis for setting nutrient intake recommendations across countries. The foundation therefore asked the National Academies of Sciences, Engineering, and Medicine to do two things: first, to convene a workshop to explore questions about the uses of nutrient intake recommendations, the frameworks used for their development, the status of nutrient intake recommendations globally, and experiences and expertise in methodological approaches; and, second, to convene a consensus study committee to assess methodological approaches that could be applied uniformly across countries in setting nutrient intake recommendations. The workshop provided a backdrop and a resource for the consensus study committee’s task. Specifically, the Bill & Melinda Gates Foundation asked the committee to focus on young children and women of reproductive age and to apply its findings to
these target population subgroups using case scenarios informed by workshop presentations and further review of global evidence and opportunities.
This committee’s work builds on the previous work of WHO, FAO, and other relevant authoritative bodies to bring international stakeholders together to exchange data, experience, and ideas in an open setting, and then to examine the current evidence, conceptualize candidate methodologies, and develop recommendations for ways to move toward the goal of standardizing methodologies for establishing nutrient intake recommendations.
The committee’s analyses, findings, and recommendations are presented in this report. The report provides a framework for how stakeholders can, within the context of a country or a region’s needs and abilities, generate a uniform approach for establishing nutrient intake recommendations that take into account culturally and context-specific food choices and dietary patterns.
The Committee on the Application of Global Harmonization of Methodological Approaches to Nutrient Intake Recommendations for Young Children and Women of Reproductive Age was supported in its task by the invaluable contributions of a number of individuals. First, many thanks are owed to the members of the committee who volunteered their time and expertise to a complex and challenging task and to the preparation of this report. Their dedication to the project was commendable. Special thanks go to the contributions of Janet King, who served as a consultant to the committee. Additional thanks go to WHO and FAO for facilitating the workshop, as well as the many individuals who gave presentations at the workshop hosted at FAO headquarters in Rome, Italy. Finally, the committee wishes to acknowledge the contributions of the study staff: Gillian Buckley, study director; Amanda Nguyen, associate program officer; and Meredith Young, senior program assistant. Finally, this project benefited from the general guidance and assistance of Ann Yaktine, director of the Food and Nutrition Board.
Robert E. Black, Chair
Committee on the Application of Global Harmonization of Methodological Approaches to Nutrient Intake Recommendations for Young Children and Women of Reproductive Age
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Contents
1 INTRODUCTION AND PROBLEM STATEMENT
2 CONCEPTUAL FOUNDATIONS OF NUTRIENT REFERENCE VALUE DEVELOPMENT
Guiding Principles in Setting Nutrient Reference Values
3 A HARMONIZED PROCESS FOR NUTRIENT REFERENCE VALUE DEVELOPMENT
Key Steps in the Process for Deriving Nutrient Reference Values
Findings, Conclusion, and Recommendation
Harmonizing the Process for Nutrient Reference Values Using Exemplar Nutrients
Findings and Conclusions for Zinc
Findings and Conclusions for Iron
Findings and Conclusions for Folate
Applications of Nutrient Reference Values in Low- and Middle-Income Countries
5 FUTURE DIRECTIONS AND DATA GAPS
Advantages of Harmonizing Methodologies to Derive Nutrient Reference Values
Steps Required to Encourage Commitment to the Guidelines
Moving Forward Toward Harmonization
D Tools and Methods to Evaluate the Risk of Bias in Individual Studies
E Scaling Methods to Extrapolate from Reference Values of One Age Group to Another
Acronyms and Abbreviations
AHRQ | Agency for Healthcare Research and Quality |
AI | adequate intake |
AMDR | acceptable macronutrient distribution range |
ANR | average nutrient requirement |
AR | average requirement |
ASEAN | Association of Southeast Asian Nations |
COMA | United Kingdom Committee on Medical Aspects of Food and Nutrition Policy |
CV | coefficient of variation |
D-A-CH | Nutrition Societies of Germany, Austria, Switzerland |
DRI | Dietary Reference Intake |
DRV | dietary reference value |
EAR | estimated average requirement |
EDTA | ethylenediaminetetra-acetic acid |
EFSA | European Food Safety Authority |
EFZ | endogenous fecal zinc |
EURRECA | European Micronutrient Recommendations Aligned |
FAO | Food and Agriculture Organization |
FZA | fractional zinc absorption |
GRADE | Grading of Recommendations, Assessment, Development and Evaluation |
INL | individual nutrient level |
IOM | Institute of Medicine |
IUNS | International Union of Nutritional Sciences |
IZiNCG | International Zinc Nutrition Consultative Group |
LOAEL | lowest observed adverse effect level |
LRNI | lower reference nutrient intake |
LTI | lowest threshold intake |
NIV | nutrient intake value |
NL | Netherlands Food and Nutrition Council |
NNR | Nordic Nutrition Recommendations |
NOAEL | no observed adverse effect level |
NRV | nutrient reference value |
OHAT | Office of Health Assessment and Translation |
PICO/PECO | population, intervention/exposure, comparator, and outcome of interest |
PRI | population reference intake |
RCT | randomized controlled trial |
RDA | recommended dietary allowance |
RI | recommended intake |
RNI | reference nutrient intake |
SADC | Southern African Development Community |
SRDR | Systematic Review Data Repository |
SUL | safe upper level |
TAZ | total absorbed zinc |
UK | United Kingdom |
UL | tolerable upper intake level |
UNICEF | United Nations Children’s Fund |
UNL | upper nutrient level |
WHO | World Health Organization |