Rethinking the Acceptable Macronutrient Distribution Range for the 21st Century: A Letter Report (2024)
Chapter: Summary
Summary
BACKGROUND
The Dietary Reference Intakes (DRIs) are authoritative recommendations used by health professionals in dietary assessment and counseling and in development of educational materials for consumers and patients. DRIs are also used by scientists in designing and interpreting research as well as users of national nutrition survey data. DRIs are integral to dietary recommendations across federal food and nutrition programs and serve as a resource for developing food and nutrition policies and regulations as well as development of national dietary guidelines.
A component of the DRIs is the Acceptable Macronutrient Distribution Range (AMDR). AMDRs are reference values for energy intakes from carbohydrate, fat, and protein that were established in the mid-1990s to provide health professionals with guidance on dietary intake recommendations for energy-containing macronutrients associated with micronutrient intake adequacy and decreased risk of chronic disease. To achieve this goal, an intake range based on the percent of total calories was established. In 2019, a committee of the National Academies of Sciences, Engineering, and Medicine (the National Academies) updated the review of DRIs for sodium and potassium to include a structured and consistent approach to chronic disease risk reduction for these two nutrients. The application of the AMDR approach for these nutrients was considered but not adopted. A new DRI category, the Chronic Disease Risk Reduction (CDRR) value, was created and applied to sodium. Development of the CDRR values, in part, prompted the question of whether the
AMDR should be retained, removed, or modified within this expanded DRI framework. Thus, the Standing Committee for the Review of the Dietary Reference Intake Framework was asked to consider whether the AMDR is needed within the expanded DRI framework that includes CDRR considerations.
THE COMMITTEE’S TASK
In 2023, the U.S. Department of Agriculture Agricultural Research Service asked the National Academies to convene a committee to carry out a review of whether the AMDR concept adds value within the expanded DRI framework that includes chronic disease risk considerations. The committee was asked to provide justification for its findings through an assessment of the considerations related to either retaining or removing the AMDR.
To carry out its task, the committee gathered data from current peer-reviewed published literature and held a virtual workshop that included speakers from a range of different organizations that use the AMDR in planning and/or assessment of individual and/or group diets.
SHOULD THE AMDR BE RETAINED?
The committee considered whether to retain the AMDR. One possible reason for retaining AMDRs is the widespread application of these ranges by a variety of users to plan and assess diets with the goal of achieving a low prevalence of macronutrient energy intakes outside the recommended ranges. This suggests that the AMDR can be used as a general guideline for planning and evaluating diets. Among the concerns for retaining the AMDR is that it fails to capture nutrient quality for each macronutrient, for example, complex versus simple carbohydrates or complete versus incomplete proteins. Another overarching concern is the strength, or lack of, and quality of the evidence to support the AMDR values. Considering the scientific standards of today, it is unclear whether the evidence base used to define the AMDRs would meet the updated criteria established for setting DRI values based on chronic disease risk.
FINDINGS, CONCLUSIONS, AND RECOMMENDATIONS
Findings
The committee found that users of AMDRs reported they applied the values as a primary or secondary tool for assessment of diets or for dietary planning. Some users of the AMDR reported that it provided a
check for dietary quality after using other DRI values to evaluate adequacy, safe upper levels of intake, and/or chronic disease risk reduction.
The AMDR recommendations were predicated on a narrative literature review that yielded estimates based on subjective interpretation of the data (IOM 2002/2005; chapter 11). A concern recognized by the committee was that except for essential fatty acids, the AMDR concept was not linked to macronutrient quality. Applying the AMDRs is another concern because guidance on using DRIs in dietary assessment and planning is based on distributions and probability, and the AMDRs do not fit this paradigm. These issues were not addressed in documentation of the development of the AMDR values.
Conclusion
The committee concludes that the approach used to derive the AMDRs is not consistent with current evidence-based standards. A future DRI review of macronutrients and their constituent nutrients and other food substances needs to consider the quality and strength of the evidence associated with chronic disease risk.
Recommendations
Recommendation 1: In developing future reviews of Dietary Reference Intakes (DRIs) for macronutrients, the federal DRI working group should remove the Acceptable Macronutrient Distribution Range from the panel of nutrient intake values considered in the DRI framework.
Recommendation 2: In future reviews of Dietary Reference Intakes for macronutrients, the expert review panel should consider macronutrient quality, the requirement for essential nutrients associated with macronutrient intake, and the reference values for their constituent nutrients and other food substances as supported by the evidence.
CONSIDERATIONS
The committee recognizes that in the interim, and until an alternative approach is provided, some users may wish to continue to apply the AMDR values. However, users should realize their limitations if they continue to employ these ranges. The committee suggests the use of existing DRIs (e.g., Estimated Energy Requirement [EER], Estimated Average Requirement [EAR], Recommended Dietary Allowance [RDA], Adequate
Intake [AI], Tolerable Upper Intake Level [UL], CDRR) as appropriate, for dietary assessment and planning. If there is a well-defined need for an alternative to the AMDR, it should be in the purview of the relevant DRI macronutrient expert review panel.
