Rethinking the Acceptable Macronutrient Distribution Range for the 21st Century: A Letter Report (2024)
Chapter: 2 Background and Statement of Task
2
Background and Statement of Task
The Dietary Reference Intakes (DRIs) are a set of evidence-based nutrient reference values used to plan and assess nutrient intakes of the general populations of the United States and Canada. DRI values are established for different age and/or sex groups and include values related to maintaining adequacy, reducing risk of chronic disease, and avoiding toxicity. DRIs provide authoritative recommendations that are used by health professionals in dietary counseling and in the development of educational materials for consumers and patients, by scientists in designing and interpreting research, and by users of national nutrition survey data. The values also underpin several federal food and nutrition programs, policies, and regulations, including food fortification, nutrition labeling, and the development of national dietary guidelines.
The Institute of Medicine’s (IOM) first report on DRIs for macronutrients developed a new DRI value called the Acceptable Macronutrient Distribution Range (AMDR)—these AMDRs are DRI values for the energy intake ranges of carbohydrates, fat, and protein (IOM, 2002/2005) that were intended to incorporate into the DRIs the evidence that macronutrient intake distributions may contribute to risk of chronic diseases. AMDRs were estimated for adults based on evidence to suggest a role in chronic diseases and to ensure sufficient intakes of essential nutrients that do not exceed the Tolerable Upper Intake Levels for all age groups.
A subsequent updated review of DRIs for sodium and potassium included a structured and consistent approach to chronic disease risk reduction for these nutrients (NASEM, 2019). This approach created a
new DRI, the Chronic Disease Risk Reduction (CDRR) value for sodium, which expanded the DRI framework. Development of the CDRR value, in part, prompted the question of whether the AMDR should be retained, removed, or modified within the framework.
THE COMMITTEE’S TASK
In 2023, the U.S. Department of Agriculture Agricultural Research Service asked the National Academies of Sciences, Engineering, and Medicine’s Standing Committee for the Review of the Dietary Reference Intake Framework to carry out a review to respond to the question of whether the AMDR concept adds value within the expanded DRI framework that includes CDRR considerations. The committee was further asked to provide justification for its findings through an assessment of the considerations related to either retaining or removing the AMDR. This letter report responds to that request and will be used to inform future DRI reviews on macronutrients. The committee’s Statement of Task is shown in Box 2-1.
BOX 2-1
Statement of Task
The National Academies of Sciences, Engineering, and Medicine will appoint a standing committee to review the Dietary Reference Intake (DRI) framework, structure, and process relevant to future DRI reviews. The committee will consider past experiences and learning from previous DRI reports, including the report on “Guiding Principles for Basing DRIs on Chronic Disease”; the recent meeting of experts, “Strategic Planning for a New Review of Macronutrient Dietary Reference Intakes”; and other relevant documents related to the DRI process, such as “Development of DRIs 1994–2004: Lessons Learned and New Challenges.” The standing committee will produce approximately two letter reports a year in response to questions relevant to a range of questions relevant to the DRI framework and structuring new DRI reviews as questions arise from various DRI consensus committees. The sponsor will utilize its learning from the standing committee discussions to inform future DRI reviews, including a review of DRIs for macronutrients.
This third letter report will comment on whether the Acceptable Macronutrient Distribution Range (AMDR) is necessary within the expanded DRI framework that includes chronic disease risk reduction considerations. The report will include the committee’s assessment of the considerations related to either retaining or removing the AMDR.
APPROACH TO THE TASK
The committee approached its task first by gathering information from presentations given at an open meeting with stakeholders from a range of relevant backgrounds and organizational affiliations, including industry, clinical, military, and public health settings (see Appendix B). This allowed the committee a first-hand perspective on how professionals in the field are using the AMDR values. It also provided insight into the challenges and limitations associated with operationalizing the AMDR in diverse settings. The committee gathered additional information from existing peer-reviewed published literature sources on how the AMDR values are being applied in nutrition research.
ORGANIZATION OF THE REPORT
This report is organized into six chapters that describe the uses and limitations of the AMDR and considerations for alternative approaches to its application in the context of the DRI framework. Chapter 3 provides historical context for the DRI framework and how the AMDR was developed within the framework. Chapter 4 describes uses and applications of the AMDR as reported to the committee by users in a data-gathering workshop and from the peer-reviewed literature. Chapter 5 describes limitations of the AMDR. Chapter 6 includes the committee’s recommendations in response to its task and the implications of changes to the AMDR for users. References are provided in Appendix A. The open session agenda is given in Appendix B, literature search results are in Appendix C, and biographical sketches of the committee members are presented in Appendix D.
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