New Report Calls for Comprehensive Redesign of Process for Updating Dietary Guidelines for American
WASHINGTON – Although the process used to develop the Dietary Guidelines for Americans (DGA) has become more evidence-based since its inception more than 30 years ago, it is not currently positioned to effectively adapt to changes such as food diversity and chronic disease prevalence, while also ensuring the integrity of the process, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine. The U.S. Department of Agriculture (USDA) and U.S. Department of Health and Human Services (HHS) should comprehensively redesign the process for updating the DGA to improve transparency, promote diversity of expertise and experience, support a deliberative process, foster independence in decision-making, and strengthen scientific rigor.
The Dietary Guidelines for Americans provide nutritional and dietary information to promote health and prevent chronic disease. Reviewed and updated every five years, the guidelines underpin all federal nutrition policies and programs, such as the National School Lunch Program and the Special Supplemental Nutrition Program for Women, Infants, and Children. The process for updating the DGA begins with an independent evaluation of the scientific evidence by the Dietary Guidelines Advisory Committee (DGAC) -- a group selected and convened by USDA and HHS. The conclusions and recommendations of the DGAC are then submitted to the secretaries of USDA and HHS in the form of a scientific report. The DGAC's report is only advisory and does not constitute draft policy, though it does serve as the scientific evidence base for updating the subsequent edition of the DGA. The DGA themselves are then developed by USDA and HHS.
The juxtaposition of the five-year DGA cycle and the two-year term for each DGAC constrains the overall system, including the time available to complete necessary tasks, the report says. The DGAC conducts all tasks associated with scientific review, limiting opportunities for a truly deliberative process with the nutrition community, technical experts, and the public. The report recommends a redistribution of the tasks of the DGAC to three separate groups with more targeted expertise in order to leverage the five-year cycle more effectively: 1) a Dietary Guidelines Planning and Continuity Group to monitor for and curate new evidence, identify and prioritize topics for inclusion in the DGA, and provide strategic planning support across DGA cycles; 2) technical expert panels to provide content and methodological consultation during evidence evaluation; and 3) a Dietary Guidelines Scientific Advisory Committee to interpret the scientific evidence and draw conclusions.
The report recommends that the secretaries of USDA and HHS carry out several other actions in a number of areas as part of the process redesign:
- Enhance Transparency: A clear explanation should be given when the DGA omit or accept only parts of conclusions from the DGAC Scientific Report. Enhancing transparency -- for example, by appropriately balancing individual biases and conflicts of interest -- is vital to engendering public trust in the process, as well as providing assurance that decisions were made free of undue influences. Opportunities for participation and engagement from stakeholders including the public, academia and researchers, advocacy groups, professional organizations, the food sector, and federal agencies should be enhanced, as it is critical to fostering diversity and increasing trustworthiness of the process.
- Strengthen the Evidence Base: Methodological approaches and scientific rigor for evaluating the evidence should be strengthened by using validated, standardized processes and methods with the most up-to-date data. It is critical that, for example, the Nutrition Evidence Library is aligned with best practices for conducting systematic reviews and uses appropriate methods.
- Advance Methods Used: Processes and actions should be based on the best available evidence, requiring that the analyses used be continuously improved and advanced. Food pattern modeling should better reflect complex interactions, variabilities in food composition and consumption, and range of possible healthful diets. In addition, standardizing the methods and criteria for establishing “nutrients of concern” would lead to consistent development of quantitative thresholds of inadequacy or excess. To help more clearly define the roles and limitations of diet in reducing chronic disease risk, the report recommends a systems science approach, which accounts for complex relationships, for example, biological, behavioral, social, and environmental interactions and pathways.
In terms of the guidelines’ scope, future DGA should focus on the general public across the entire life span, not just healthy Americans ages 2 years and older, the report says. Given the range in health status and the prevalence of chronic diseases in the population, as well as the importance of nutrition to pregnant women and children from birth to 24 months, it is essential that future DGA be developed for all Americans whose health could benefit by improving diet. The breadth and content of each DGAC report could vary because not all topics may require a detailed review every five years; only those topics with enough new data to generate a full review would be considered for in-depth evaluation in the next DGA cycle.
The study was sponsored by the U.S. Department of Agriculture. The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. The National Academies operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln.