The Development of DRIs 1994-2004: Lessons Learned and New Challenges: Workshop Summary (2008)

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Marla Sheffer and Christine Lewis Taylor, Rapporteurs Food and Nutrition Board 

THE NATIONAL ACADEMIES PRESS   500 Fifth Street, N.W.   Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Govern- ing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineer- ing, and the Institute of Medicine. This study was supported by Contract No. HHSP2332004509XI TO #8 between the National Academy of Sciences and U.S. Department of Health and Human Ser- vices; Contract No. AG-0202-P-06-0014 between the National Academy of Sciences and U.S. Department of Agriculture; and Contract No. 4500164550 between the National Academy of Sciences and Health Canada. Additional support came from the Canadian Institutes of Health Research. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for this project. International Standard Book Number-13: 978-0-309-11562-9 International Standard Book Number-10: 0-309-11562-0 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu. For more information about the Institute of Medicine, visit the IOM home page at: www.iom.edu. Copyright 2008 by the National Academy of Sciences. All rights reserved. Printed in the United States of America. The serpent has been a symbol of long life, healing, and knowledge among almost all cultures and religions since the beginning of recorded history. The serpent ad- opted as a logotype by the Institute of Medicine is a relief carving from ancient Greece, now held by the Staatliche Museen in Berlin. Suggested citation: Institute of Medicine (IOM). 2008. The development of DRIs 1994–2004: Lessons learned and new challenges—workshop summary. Washing- ton, DC: The National Academies Press. 

“Knowing is not enough; we must apply. Willing is not enough; we must do.” —Goethe Advising the Nation. Improving Health. 

The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Acad- emy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding en- gineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineer- ing programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Charles M. Vest is presi- dent of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Insti- tute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sci- ences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Coun- cil is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair, respectively, of the National Research Council. www.national-academies.org 

PLANNING COMMITTEE FOR DIETARY REFERENCE INTAKES REVIEW WORKSHOP JOHN W. SUTTIE (Chair), Department of Biochemistry, University of Wisconsin, Madison STEPHANIE A. ATKINSON, Nutrition and Metabolism Research Laboratory, Department of Pediatrics, McMaster University, Hamilton, Ontario JANET C. KING, University of California at Berkeley and Davis, Children’s Hospital Oakland Research Institute, Oakland SUSAN TAYLOR MAYNE, Division of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT HUGUETTE TURGEON O’BRIEN, Department of Food Sciences and Nutrition, Laval University, Quebec City, Quebec WILLIAM M. RAND, Department of Public Health and Family Medicine, Tufts University School of Medicine, Boston, MA ROBERT M. RUSSELL, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA Staff CHRISTINE LEWIS TAYLOR, Study Director and Scholar HEATHER DEL VALLE, Research Associate SANDRA AMAMOO-KAKRA, Program Associate MARLA SHEFFER, Consultant Writer, Orleans, Ontario  

FOOD AND NUTRITION BOARD* DENNIS M. BIER (Chair), Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX MICHAEL P. DOYLE (Vice Chair), Center for Food Safety, University of Georgia, Griffin DIANE BIRT, Center for Research on Dietary Botanical Supplements, Iowa State University, Ames YVONNE BRONNER, School of Public Health and Policy, Morgan State University, Baltimore, MD FERGUS M. CLYDESDALE, Department of Food Science, University of Massachusetts, Amherst GORDON L. JENSEN, Department of Nutritional Sciences, Pennsylvania State University, University Park REYNALDO MARTORELL, Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA SUSAN TAYLOR MAYNE, Division of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT SANFORD A. MILLER, Center for Food, Nutrition, and Agriculture Policy, University of Maryland, College Park J. GLENN MORRIS, JR., Emerging Pathogens Institute, University of Florida, Gainesville SUZANNE P. MURPHY, Cancer Research Center of Hawaii, University of Hawaii, Honolulu JOSE M. ORDOVAS, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA MARTIN A. PHILBERT, School of Public Health, University of Michigan, Ann Arbor JIM E. RIVIERE, College of Veterinary Medicine, North Carolina State University, Raleigh REBECCA J. STOLTZFUS, Division of Nutritional Sciences, Cornell University, Ithaca, NY PATRICK J. STOVER, Institute for Nutritional Genomics, Division of Nutritional Sciences, Cornell University, Ithaca, NY WALTER C. WILLETT, Department of Nutrition, Harvard School of Public Health, Boston, MA Staff LINDA D. MEYERS, Director GERALDINE KENNEDO, Administrative Assistant ANTON L. BANDY, Financial Officer *IOM boards do not review or approve individual reports and are not asked to endorse conclusions and recommendations. The responsibility for the content of the summary rests with the rapporteurs and the institution. vi 

Reviewers This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for 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 wish to thank the following individuals for their review of this report: Frances Seligson, Hershey, PA John W. Suttie, Department of Biochemistry, University of Wisconsin John E. Vanderveen, Food and Drug Administration, Rockville, MD Susan Whiting, College of Pharmacy and Nutrition, University of Saskatchewan, Canada Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the final draft of the report before its release. The review of this report was overseen by Hugh Tilson, M.D., Dr.P.H., M.P.H., University of North Carolina, who was appointed by the Institute of Medicine. He was responsible for mak- ing certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the author and the institution. vii 



Contents ACRONYMS xiii PREFACE xv 1 WORKSHOP INTRODUCTION 1 Welcome and Opening Remarks, 1 John Suttie Overview of Current DRI Framework and Issues Raised, 3 Christine Taylor 2 CONCEPTUAL FRAMEWORK FOR DRI DEVELOPMENT: SESSION 1 11  Current Framework for DRI Development: What Are the Pros and Cons?, 13 Robert M. Russell  Case Study: Applying the DRI Framework to Chronic Disease Endpoints, 19 Paula Trumbo  Case Study: Applying the DRI Framework to Non-Chronic Disease Endpoints, 25 Allison Yates Discussion: Framework Pros/Cons; Case Studies, 29 Patsy Brannon and Alice H. Lichtenstein ix 

 CONTENTS Two Perspectives: The DRI Framework, 32 Perspective I, 32 George Beaton Perspective II, 37 Janet King Evaluating Evidence for DRI Development: What Are the Issues in Applying Systematic Evidence-Based Review Approaches to DRI Development?, 40 Alice H. Lichtenstein Risk Assessment: Is It a Relevant Organizing Structure?, 46 Elizabeth A. Yetley Discussion: Systematic Evidence-Based Review; Risk Assessment, 54 Sanford Miller Panel Discussion: In What Ways Could the Conceptual Framework Be Enhanced?, 56  Cutberto Garza, Mary L’Abbé, Irwin Rosenberg, and Barbara Stoecker 3 CRITERIA FOR SCIENTIFIC DECISION MAKING: SESSION 2 63  Selecting Endpoints: What Are the Issues and What Are the Options for Criteria?, 64 Irwin Rosenberg  Dose–Response Data: Are There Options for Dealing with Limited Data?, 68 Susan Taylor Mayne  What Are the Challenges in Addressing Extrapolation/ Interpolation for Unstudied Groups?, 77 Stephanie A. Atkinson  What Are the Challenges in Addressing Adjustment for Data Uncertainty?, 81 Hildegard Przyrembel  Estimating Dietary Intake: What Are the Implications for DRI Development?, 87 Amy Subar  Highlights of Other Important Issues: Physiological, Environmental, and Genomic Factors, 93 Cutberto Garza 

CONTENTS xi 4 GENERAL GUIDANCE FOR USERS OF DRIs: SESSION 3 99  Overview: Issues Raised About General Guidance for Users, 100 Christine Taylor Discussion, 102 Johanna Dwyer  Special Challenges: Planning and Assessing the Total Diet— What Are the Issues and What Are the Options for Enhanced Guidance?, 104 Assessing the Total Diet, 105 Suzanne Murphy Planning the Total Diet, 107 Susan Barr Discussion, 110 Patricia Guenther and Krista Esslinger  Special Challenges: What Are the Issues Related to a Framework for Individual-Level and Group-Level Applications?, 114 Valerie Tarasuk Discussion, 117 Gerard Dallal  Panel Discussion: In What Ways Could the Guidance for Users of DRIs Be Enhanced?, 119  Danielle Brulé, Mary Frances Picciano, William Rand, and Linda Van Horn 5 LOOKING TO THE FUTURE PROCESS FOR DRI DEVELOPMENT: SESSION 4   123  Emerging Issues: What New Challenges Might the Future Hold?, 124 Catherine Woteki  There a Need to Enhance Transparency of the Decision- Is Making Process?, 128 Robert M. Russell Opportunities for Stakeholder Input in IOM Activities, 133 Linda D. Meyers  What Are the Criteria Options for Determining When to Update/Review Existing DRIs?, 136 John Suttie 

xii CONTENTS What Are the Considerations in Specifying “New” Nutrient Substances for DRI Study?, 138 Peter Greenwald Panel Discussion: Reflections on What We Have Heard About the Process of DRI Development, 145  Mary Bush, Jean-Pierre Habicht, Suzanne Harris, Van Hubbard, and Molly Kretsch 6 SUMMARY AND CLOSING REMARKS 151 John Suttie Paul Coates REFERENCES 155 APPENDIXES A Workshop Agenda and Background Materials 161 B Workshop Presenters, Discussants, Panelists, and U.S./Canadian Sponsor Representatives 169 C Brief List of Reoccurring Workshop Discussions 175 D Schematic Used by Workshop Planning Committee: Activities Associated with DRI Development 179 

Acronyms AI Adequate Intake ALA a-linolenic acid AMDR Acceptable Macronutrient Distribution Range AROI Acceptable Range of Oral Intake ATBC Alpha-Tocopherol Beta-Carotene BMI body mass index BMR basal metabolic rate BW body weight CDC Centers for Disease Control and Prevention CHD coronary heart disease CV coefficient of variation CVD cardiovascular disease DHA docosahexaenoic acid DNA deoxyribonucleic acid DRI Dietary Reference Intake EAR Estimated Average Requirement EC European Commission EER Estimated Energy Requirement EFSA European Food Safety Authority EPA eicosapentaenoic acid EU European Union xiii 

xiv ACRONYMS FACA Federal Advisory Committee Act FDA U.S. Food and Drug Administration FFQ food frequency questionnaire FNB Food and Nutrition Board IOM Institute of Medicine ISU Iowa State University LDL low-density lipoprotein LOAEL lowest-observed-adverse-effect level NAS National Academy of Sciences NCI National Cancer Institute NHANES National Health and Nutrition Examination Survey NIH National Institutes of Health NOAEL no-observed-adverse-effect level NRC National Research Council OPEN Observing Protein and Energy Nutrition PICO population, intervention, comparator, outcome RAE retinol activity equivalent RDA Recommended Dietary Allowance RNI Recommended Nutrient Intake SD standard deviation SEBR systematic evidence-based review (also abbreviated in some documents as SR) TSH thyroid stimulating hormone UF uncertainty factor UK United Kingdom UL tolerable upper intake level USDA U.S. Department of Agriculture WHO World Health Organization WIC Special Supplemental Nutrition Program for Women, Infants and Children 

Preface In what ways can the process for developing Dietary Reference Intakes (DRIs) be enhanced? The workshop entitled “The Development of DRIs 1994–2004: Lessons Learned and New Challenges” offered a valuable window into the issues and challenges inherent in the development of nutri- ent reference values. The dialogue—carried out under the auspices of the Institute of Medicine (IOM), Food and Nutrition Board (hereafter referred to jointly as the IOM)—was enriched by the 10 years of experience in de- riving the expanded set of values known as the DRIs, plus the decades of experience that grounded the earlier Recommended Dietary Allowances for the United States and the Recommended Nutrient Intakes for Canada. The lessons learned and the knowledge gained will guide decisions about the next phase of the DRIs. To paraphrase one participant, we are now asking better questions. In 2006, the IOM, with support from the United States and Canadian governments, undertook an effort to synthesize the research needs identi- fied during the 10 years of DRI development. While the workshop sum- marized here was predicated on the fact that the development of DRIs is improved by better data, its focus was different. Its goals were to examine the framework and conceptual underpinnings for developing DRIs and to identify issues important for enhancing the process of DRI development.   Agreement is lacking as to whether the preferred or appropriate term is “framework,” “ap- proach,” “model,” or “paradigm.” The term generally used in this summary is “framework.” However, given the lack of consensus, no efforts were made to change speakers’ or discussants’ remarks to universally refer to a single term. xv 

xvi PREFACE The United States and Canadian governments again served as sponsors for this important effort. The process for developing nutrient reference values in the United States and Canada has evolved over time. For example, the earliest editions undertaken by the National Research Council, dating back to the 1940s and 1950s, included fewer nutrients and less background than did later editions. Beginning in 1994, efforts overseen by the IOM resulted in DRIs that specified several kinds of reference values and provided more volumes of accompanying explanation as well as guidance for users. These changes, of course, were a function of the increasing knowledge base in the field of nutrient requirements as well as evidence of the consequences of excessive intake. However, they were also due to the increasing interest in providing transparency for the decision-making process and in communicating better with those responsible for making the public health policy that depends on the reference values. The workshop was designed to use the existing framework for DRI development as a basis for the discussions and to consider the components of the framework in sequence. Consideration of the pros and cons of the current conceptual underpinnings of the framework opened the workshop, followed by the general “road map” for decision making and the needed scientific criteria. Next, the challenges associated with providing guidance for users were explored. The workshop concluded with an array of issues germane to the future process for developing DRIs, including strategies for updating and revising existing DRIs and opportunities for stakeholder input. Many topics were interrelated and common themes often emerged during different discussions. Transparency and the need for more informa- tion on the rationale behind the decisions made were important themes sounded during the workshop. There was also interest in determining a method whereby the uncertainty surrounding the reference values could be better articulated and made known to users. In looking to the future, the advantages of focusing on single nutrients or groups of similar nutrients were highlighted. Appendix C of this summary contains a brief listing of reoccurring workshop discussions and may be useful to readers. Given the history that many participants brought with them to the workshop, it was not surprising that the discussions were rich and focused. Nor was it surprising that the numerous successes of the DRI process were readily acknowledged. What was remarkable and very gratifying was the willingness of those close to the DRI process to openly discuss newer op- tions and to readily acknowledge the appropriateness of some changes. Although many presenters, discussants, and panelists expressed view­points and recommended specific strategies, their perspectives and recom­mendations should not be viewed as workshop conclusions or rec- 

PREFACE xvii ommendations. The workshop was designed to identify issues and foster discussion, not to identify consensus recommendations. The discussions will be useful in planning the next stage of DRI activities, and clearly such planning activities will benefit greatly from the workshop conversations. Christine Lewis Taylor, IOM Scholar and Study Director Linda D. Meyers, Director, Food and Nutrition Board