2015 Dietary Guidelines Advisory Committee
Topic Selection Criteria and Approaches for Examining the Evidence
The 2015 Dietary Guidelines Advisory Committee (DGAC) will examine the Dietary Guidelines for Americans, 2010, and determine topics for which new scientific evidence is likely to be available that may inform revisions to the current guidance or suggest new guidance. This document was developed to promote Committee discussion and decision-making related to the topics to be considered. Once topics are identified, refined, and prioritized, the DGAC, with support from Federal staff, can determine how best to address the topic. The approaches available for examining the evidence are described later in this document.
Topic Selection Criteria
Proposed topic selection criteria include consideration of the scope of the Dietary Guidelines for Americans (DGA) and the likelihood that new scientific evidence on the topic may inform revisions to the current guidance or suggest new guidance:
The Dietary Guidelines for Americans address food and nutrition issues that will inform public health action to promote 1) population health or well-being, and/or 2) reduce the significant burden of avoidable disease in the U.S. population as a whole or in specific population subgroups.
Food and Nutrition Topics
- The major focus of the DGA is on foods and beverages, including groupings of these foods and beverages and dietary patterns, highlighting the amounts and combinations that should be consumed to promote health and prevent disease.
- Nutrients may be considered, but the DGA is intended to provide food-based recommendations that complement the Dietary Reference Intakes (DRIs). Changes to the DRIs are out-of-scope for the DGAC process. Examples of potential nutrient topics include:
- Nutrients of public health concern (e.g. where intakes are too low or too high)
- Topics that could demonstrate how to implement the DRIs (e.g., consider if some quantitative recommendations should be energy-adjusted for implementation)
- Topics that could complement the DRIs (e.g., provide guidance on reasonable implementation of DRIs in the USDA Food Patterns )
- Additional topics may address factors that have the potential to enhance implementation of the DGA. Examples include:
- Social, behavioral, and/or environmental factors that may improve dietary intake or calorie balance
- Principles that ensure food is safe for consumption
- The target population of the DGA is the general U.S. population ages 2 years of age and older. This includes children, adolescents, adults, and older adults.
- The age span from birth to 24-months of age is not in the scope of the 2015 DGAC as a primary target population at this time. This group is being addressed in a separate effort which is considering topics pertinent to infant and toddler intake, such as breastfeeding, formula feeding, and introduction of foods and their relationship with infant and toddler outcomes.
- The scope of the DGAC's work includes maternal intake. This includes optimal dietary intake during pregnancy, postpartum, and lactation, as it relates to maternal health and pregnancy outcomes.
- Pertinent subpopulations, including those who are at-risk for nutrition-related chronic disease and/or subpopulations at nutritional risk (e.g., low socioeconomic status), are also included.
Public Health Outcomes
- Topics to be considered should have the potential to impact one or more food and nutrition-related outcomes of public health concern. Examples include the following:
- Health Outcomes: Body weight status, cardiovascular disease, type 2 diabetes, cancer, bone health, and prevention of foodborne illness (Relevant biomarkers may also be considered, as appropriate.)
- Diet-related Outcomes (relevant to social, behavioral, and environmental topics): Intake of foods, food groups, dietary patternsutrients of public health concern, diet quality, and dietary behaviors
Likelihood of Informing Recommendations
When selecting topics, the DGAC may consider the likelihood of a review of the topic potentially informing dietary guidance. Potential criteria to consider include the following:
- A review of the current evidence on the topic may inform the development of new dietary guidance for Americans ages 2 years and older.
- A review of the current evidence on the topic may result in a change or elaboration in existing recommendations.
- The topic represents important uncertainty or a knowledge gap for decision makers.
- Addresses important controversy or dilemma in public health nutrition
- There is a degree of urgency for guidance (e.g., significant area of public health concern, emerging area for public health action)
- Addresses a common practice in public health nutrition for which there is no government guidance
Approaches for Examining the Evidence
Once topics have been refined so that they are targeted and answerable, the DGAC, with support from Federal staff, can determine the best approach for examining the evidence on the topic. The DGA should be based on the preponderance of current scientific evidence. The primary approaches for examining the evidence will be systematic reviews, data analyses, and/or food pattern modeling analyses requested by the DGAC and completed with support from Federal staff. Additional sources of information may include existing high-quality evidence-based reports, input from expert guest speakers, as well as oral and written comments from the public. It is expected that topics will be considered using one or a combination of the following:
- Systematic reviews: If sufficient new evidence is available that warrants a full systematic review, the USDA Nutrition Evidence Library (NEL) can support the completion of DGAC systematic reviews. Updates to NEL reviews conducted by the 2010 DGAC and/or systematic reviews to complement other sources of evidence may also be conducted. To promote consistency, a common framework for all of the DGAC systematic reviews is desirable.
- Food pattern modeling analyses: USDA staff are available to conduct these analyses that determine the hypothetical impact on nutrients in and the adequacy of USDA Food Patterns, in relation to potential dietary guidance, when specific modifications are made.
- Data analyses: Federal staff from HHS and USDA are available to conduct data analyses related to intakes of foods and/or nutrients, obesity, food safety, the food supply, and other topics.
- Existing high-quality evidence-based reports: To prevent duplication of effort and promote time and resource management, the DGAC may choose to consider all or aspects of existing high-quality systematic review, food pattern modeling, and data analysis reports to fully or partially address a topic.
- Public comments: Oral and written comments are received from the public throughout the DGAC's work. Comments from the public can bring to light new issues, new approaches to current issues, and emerging evidence.