August 18, 2019
Barbara Schneeman, PhD
Chair, 2020-2025 Dietary Guidelines Advisory Committee
c/o Eve Stoody, PhD
Designated Federal Officer
Center for Nutrition Policy and Promotion, Food and Nutrition Service
U.S. Department of Agriculture
3101 Park Center Drive, Room 1034
Alexandria, VA 22301
Re: Posted Nutrition Protocols and Utilization of Nutrition Science
Dear Dr. Schneeman:
The Academy of Nutrition and Dietetics (the "Academy") appreciates the opportunity to submit comments to the 2020 Dietary Guideline Advisory Committee (DGAC or the "Committee") regarding issues and protocols relevant to the development and integrity of its forthcoming scientific report "outlin[ing] its science-based recommendations and rationale"1 for the 2020-2025 Dietary Guidelines for Americans (the "Dietary Guidelines," "Guidelines," or DGAs). Representing more than 107,000 registered dietitian nutritionists (RDNs), nutrition and dietetic technicians, registered (NDTRs), and advanced-degree nutritionists, the Academy is the largest association of food and nutrition professionals committed to accelerating improvements in global health and well-being through food and nutrition. Our members have helped conduct, review, and translate nutrition research for the DGAs since their inception, and will work to help consumers, industry, and schools choose meal patterns in accordance with the final recommendations of the Secretaries of the U.S. Department of Agriculture and the U.S. Department of Health and Human Services (collectively, the "Departments").
The Academy is pleased with the work to-date of the DGAC and the Departments and recognizes the enormous task before it in developing the 2020-2025 DGAs and the newly required guidelines for Americans from birth to two-years-old. Below, we respectfully offer comments and recommendations related to the following issues:
- The importance of clarity regarding the DGA's target audience given the prevalence and variety of chronic diseases in the U.S. population.
- The need for additional research and funding to close identified gaps.
- The need for enhanced transparency throughout the DGA development process, including work by the Departments after issuance of the scientific report.
- The unique nature of nutrition science, its value, and its role in developing actionable dietary recommendations.
- Proposed protocols and the DGAC's intended use of existing systematic reviews.
- The need to address sustainability, avoid arbitrarily restricting the DGAC's time to complete its work, and focus on the DGA's implementation and dissemination.
A. Commitment to Science-Based Dietary Guidelines
The Academy has full confidence that the Committee will fulfill its charge to "provide independent, science based advice and recommendations to be considered by USDA and HHS in the development of the 2020-2025 Dietary Guidelines for Americans."2 We strongly support meta-analysis research to back up the DGAs whenever possible. We look forward to a transparent and collaborative process for reviewing and translating the best available "science into succinct, food-based guidance that can be relied upon to help Americans choose foods that provide a healthy and enjoyable diet."3 We also underscore the importance of conducting regular, quinquennial DGAs that allow the Departments to engage on a continuing basis in scoping and other valuable evidence analysis processes. Nutrition science produces a wealth of valuable literature with substantial, beneficial application from clinical guidelines to industry formulations.
B. Focus on Primary Prevention Amid Prevalence of Chronic Disease
For 35 years, the DGAs have provided the best available scientific advice to consumers seeking to prevent or reduce their risk of diet-related diseases. This advice has never been more critical. As the most recent iteration makes clear, the DGA's "recommendations are ultimately intended to help individuals improve and maintain overall health and reduce the risk of chronic disease—its focus is disease prevention."4 While appropriate, the Academy notes this focus on primary prevention of diet-related chronic diseases and conditions is not uniformly applicable to most Americans. Two out of three American adults and one out of three children are overweight or have obesity.5 Nearly half of adults have diabetes or prediabetes,6 and roughly half of adults have high blood pressure,7 a major risk factor for heart disease and stroke. Furthermore, 13 cancers, including breast, colorectal, esophageal, and uterine, are linked to overweight or obesity.8 In total, 60% of Americans in 2014 "had at least one chronic condition, and 42% had multiple chronic conditions."9 Given the extremely high prevalence of co-morbidities and overweight/obesity, the DGAs need to go beyond mere prevention and equally focus on amelioration of these conditions by leveraging a healthy food environment and food choices.
We are fully supportive of extending DGA recommendations beyond its existing target demographic to include pregnancy and children from birth to 24 months ("B-24") as essential to improved primary prevention, including focused recommendations supporting breastfeeding. Good nutrition throughout the first two years of life helps lay the foundation for a child's future health well into adulthood. New research in the fields of neuroscience and the early origins of adult health is shedding light on how infants' brains develop, how children and adults become susceptible to diseases, and how capacities and skills are either nourished or thwarted, beginning at least during pregnancy and continuing through the first two years of life.10,11
This growing body of scientific research indicates that the foundations for lifelong health—including predispositions to obesity and certain chronic diseases—could be significantly determined by poor nutrition early in life that impacts not only a child's health, but also potentially that of the child's offspring.12 The damaging effects caused by poor nutrition in early life could have the potential to cascade down through generations of children and lock families into a cycle of poor health, making comprehensive, actionable recommendations for infants and children essential.
C. Target Audience(s)
The charter for the 2020 DGAC reminds us that the National Nutrition Monitoring and Related Research Act of 1990 (Section 301 of Public Law 101-445 codified at 7 U.S.C. 5341) instructs that [the DGAs] shall contain nutritional and dietary information and guidelines for the general public"13 The Academy strongly recommends the DGAC and Departments reconcile that instruction with the 2015-2020 DGAs' statement that its "primary audiences are policymakers, as well as nutrition and health professionals, not the general public,"14 or otherwise explain whether there has been a change in the primary audience since the 2015-2020 DGAs were published. We recognize the value in directing guidelines at the entities and individuals most able to effect the respective changes on both micro and macro levels, including registered dietitian nutritionists. At the same time, there is a potentially competing value in the guidelines being written in approachable, concise language that is easy for consumers to apply. As there are evidence-based dietary recommendations for many diet-related chronic diseases that do not match the DGAs, confusion can develop among professionals and the public about which dietary recommendations to follow if it is not clear who the DGAs target in terms of nutritional needs. We suggest the Departments consider publishing slightly different iterations of the Guidelines to specifically target intended audiences, similar to the manner in which clinical guidelines often include both clinician-focused and public-facing versions to add clarity and facilitate more effective implementation.
In addition to the DGAs' putative applicability to the general public; they are used as the scientific basis for the benefit design and certain programmatic elements of the National School Lunch and School Breakfast Programs, the Child and Adult Care Food Program and senior meals through the Older Americans Act. They also are used by state and local governments and health departments across the country as the basis for many of their nutrition policies and programs, where food may be sold or served on public property or public funds are used.
D.Research Needs: Limitations Encountered and Gaps Identified
The Academy encourages the federal government to enhance its investment in critical food and nutrition research to build on the work the DGAC and the Departments are doing in the DGA development process. We note that despite continual enumeration of the same research gaps by previous DGACs, this chasm continues to widen from a lack of investment in addressing these fundamental research questions.15 Specifically, we need prospective, translational research in humans including the entire life cycle, comparative effectiveness research, and population based policy studies that examine facilitators and barriers to healthy community environments and access to safe, high quality nutrition care. Accordingly, we reiterate our previous recommendation that the USDA and HHS form an advisory group to address this concern; work with the National Institutes for Health (NIH), National Institutes for Food and Agriculture (NIFA), the Centers for Disease Control and Prevention (CDC), and Congress to make funding available to conduct this research; define best practices and methodologies to address the identified needs; and establish a process to identify and resolve lingering research needs. The limited funding for these fundamental health research efforts are resulting in the United States slipping from the leadership role in the global scientific community. At its core, the development of evidence-based guidelines hinge upon the quality and quantity of the science available to make recommendations.
We are pleased that the DGAC's charge directs it to "provide its advice and recommendations to[, among others,] the USDA Under Secretar[y] of . . . Research, Education, and Economics (REE). With the tremendous resource of respected scientists at its disposal, the agencies and offices of REE are exactly the right entities to undertake the necessary research consumers, public health practitioners, and the government have been begging for since the first iteration of the DGAs. The research these agencies undertake is essential to the scientific progress necessary to improve the health and well-being of Americans. The recent losses of staff and infrastructure within the USDA Agricultural and Food Research Institute (AFRI) being moved from Washington, D.C. to Kansas City will have a rippling effect for years in the development of science in the areas of food and agriculture research. It will not only be incalculably devastating to the DGAs and the health of the nation but will also be woefully fiscally irresponsible to decimate these offices and agencies by forcing an ill-considered relocation that results in mass retirements and resignations of some the nation's leading scientists.
E. Health Equity
The Academy's strategic plan encourages a shift in focus toward health equity, social determinants of health, and transparent involvement of broader constituencies throughout the DGA process. The Academy believes that the DGAs and the Departments' other initiatives to improve the nutritional status of Americans, reduce obesity and other diet-related chronic diseases, and increase food security must include efforts to achieve health equity and reduce health disparities. We urge the Committee to include in its scientific report strategies for achieving health equity, including how collaboration across all sectors and levels of government to implement policies can improve public health and provide equitable access to healthy and affordable food, clean water, and effective nutrition care services.
Racial and ethnic minorities experience unique health and wellness challenges and are at a greater risk of having food insecurity as well as obesity.16,17 Academy members' research, leadership and community-based efforts provide excellent examples of success stories that can be scaled up across the country to reduce disparities, including:
- The Academy's just-released comprehensive toolkit for community leaders, which guides them through a step-by-step process to identify the best solutions to improve food security in the community. This toolkit provides a plethora of resources and is free to the public at https://eatrightfoundation.org/why-it-matters/public-education/food-security-solutions/.
- The NEW Soul Study at the University of South Carolina is examining impacts on blood pressure, cholesterol levels, and weight of a plant-based, soul food diet and low-fat, standard soul food diet in the African American community.18
- The Healthy Community study "[e]xamine[d] relationships between number, type and intensity of community programs and policies (CPPs) and child nutrition[, concluding that [m]ultiple characteristics of CPPs to prevent obesity appear important to improve children's diets."19
F. Integrity of the DGA Development Process
1. Conflicts of Interest
The actual and perceived integrity of the DGA development process is absolutely paramount. The Academy agrees with the recommendation of the National Academies of Sciences, Engineering, and Medicine that, "Actual and/or perceived conflicts of interest—both financial and nonfinancial—will need to be eliminated to the extent possible or their effects be minimized and managed."20 The National Academies specifically anticipated that "those who have had relationships with industry or issue-specific advocates in the recent past could participate fairly on a panel if the nature of the relationship was incidental to the work of the panel," so long as any perceived conflicts are identified and mitigated.
Despite some claims to the contrary, there has been a distinct lack of bias and little undue, disproportionate, or non-public industry impact or contact in DGACs' development of their scientific reports. The Academy supports additional procedures and transparency to be enacted in accordance with the National Academies recommendations to ensure distinct lack of perceived or actual bias once federal officials and political appointees take the scientific report and draft the final DGAs, ignoring some recommendations and adopting others without sufficient or satisfactory explanation, which adds bias and reduces public trust of the DGAs.
2. Need for Enhanced Transparency at All Stages of the Process
Given the Departments' new, powerful role in dictating the scope of the research inquiry at the beginning of the DGA process, we agree with the National Academies that novel, substantial transparency will be especially critical at the final stage of the process, when the agencies take the DGAC's scientific report and transform it into the official Guidelines: "The federal writing team ought not be exempted from adhering to explicit and transparent standards for developing clinical practice guidelines."21
The public must have confidence that the Guidelines are indeed "based on the preponderance of the scientific and medical knowledge which is current at the time the report is prepared"22 that has not been "influenced by politics or other factors" that were noted by the National Academies.23 We strongly agree with the National Academies that, "In the steps of the process where public participation would be inappropriate, such as decision making for the DGA recommendations themselves, it will be critical for the agencies responsible for the DGA to explain to the public why key decisions were made."24
The Academy believes the need for transparency includes identifying the "HHS and USDA nutrition and health experts"25 tasked with drafting and approving the final DGAs and assuring the scientific community and the public that these individuals have the skill set to decide if the research relied upon and the final recommendations of the report are appropriate and reflect the best available science. Scientists—not politicians—should be formulating the guidelines in accordance with the statutory mandate, and it is not just the scientific community urging this: "Americans also voiced a strong preference for experts—not politicians—to develop the dietary guidelines. By a nearly 4-to-1 margin (79% to 20%), survey respondents agreed that scientists, doctors, and health experts should be able to create recommendations free of interference. . . ."26
Accordingly, to avoid conflict with the National Academies' explicit recommendations and consistent with the need for an evidence-to-decision framework as noted above, the public should expect that the agencies will provide the public with a forthcoming detailed rationale for:
- Criteria in the continuing development of protocols and systematic reviews;
- All material deviations from the DGAC scientific report to the final DGA; and
- The preponderant scientific rationale for each deviation from the Scientific Report.
II. Addressing Opportunities and Challenges in Nutrition Science
The ability to distill the nutritional factors to health and chronic disease outcomes is complex. Nutrition science presents unique challenges in research and implementation given certain structural differences from other disciplines, ethical considerations, and limited scientific and health literacy among many journalists and much of the general population. The Academy is encouraged by efforts to think about nutrition science in novel, comprehensive, and holistic ways, and we respectfully suggest the DGAC critically evaluate the existing evidence with a focus on rigor and validity as it develops its recommendations through the lenses highlighted below.
A. Scientific and Health Literacy
Scientific literacy and health literacy are lacking among many journalists and much of the general population. Journalists—particularly science journalists—are tasked with the responsibility to make nutrition, health, and behavioral sciences approachable and easily understandable for a public audience, while at the same time making it 'interesting" or contentious enough to drive internet traffic and get more clicks.27 We appreciate the observation that, "Quality science journalists are a promising model for a scientifically literate populace, but quality science journalism is increasingly difficult to locate amid the explosion of information available in our society through increasingly internetworked sources."28 These science journalists are necessary as "competent outsiders," and although "[t]he expert science journalist may not always be someone with a degree in science, . . . with time he or she has learned to navigate science communities, understand how science experts work, and can make sense of and translate technical language."29 The current need for journalists and the public to translate a single DGA intended for many targets may contribute to the confusion and misinterpretation. There is a pressing need to 1) train journalists on the science behind the DGAs and 2) provide clear and strong rationale for the translation of the scientific report into the DGAs for the journalists and the public.
We strongly support efforts to ensure the DGAs are relevant to and understood by the general public as well as science journalists and other competent outsiders. Research indicates that an individual's socio-economic status, educational attainment, numeracy, English literacy, and health status impact what elements of national nutrition guidance are used and the extent to which an individual is able to more broadly incorporate a variety of nutrient content data into the context of a healthy daily diet.30 The Academy commends recent findings on health and scientific literacy among the general public to the DGAC:
Efforts to promote healthy eating have often focused on nutrition knowledge or food preparation skills in isolation. However, such efforts may achieve limited population-level gains because they do not address the myriad of socio-ecological factors that shape dietary intake. In contrast, the emerging concept of food literacy explicitly recognizes the impact of environmental factors on people's capacity to develop and apply knowledge, skills, and behaviors that are essential to healthy eating. In concert with policy measures to create healthy food environments and address social determinants, food literacy is theorized as an integral component to improving dietary outcomes.31
These findings are consistent with the 2015 DGAC recommendation that "food and calorie label education should be designed to be understood by audiences with low health literacy, some of which may have additional English language fluency limitations."32 Academy members are renowned for their expertise in both conducting rigorous nutrition research and translating scientific information that consumers can understand and can apply to self-directed goals to improve their overall health. We hope to work closely with the Departments and other stakeholders in developing an effective implementation strategy.
B. Dietary Patterns and Nutrition as a Comprehensive Science
The Academy supports a holistic focus on nutrition and diet, particularly the Dietary Guidelines' focus on dietary patterns rather than individual nutrients and we encourage HHS and USDA to adopt these recommendations for healthy eating in the 2020-2025 Dietary Guidelines for Americans. It is imperative to translate the complex dietary patterns associated with healthy eating into a relatively simple way to deliver consumer-friendly guidance by utilizing existing knowledge of health and nutrition. As the DGAC's recommendations are translated into real dietary guidance, individuals must be able to understand the types and amounts of foods they should consume as the basis for lifelong health.
The Academy supports the use of dietary pattern analysis as a framework for generating public health recommendations and the use of the Departments' systematic reviews on the topics selected for review. It is important, however, to recognize and articulate the limitations of this approach and accordingly, support the DGAC in presenting the findings in a manner consistent with the systematic reviews' most accurate interpretation.
We note the difficulty in making inferences about the contributions that individual food groups make to the overall effect observed for a dietary pattern, and encourage use of an analytical approach to compare the contributions of these food group components to either overall scores or to the predictive performance of individual food groups.33 These analyses could help determine whether any individual food group was correctly identified as positively or negatively contributing to the pattern score and disease risk. As a result, the possibility remains that individual food groups have a diminished or even opposite effect of what is expected, an effect that could be masked by other components of the diet pattern assessment techniques that are strongly performing. These efforts will need to address the concerns of substitution in relation to the removal of foods or beverages to assess the cumulative impact of dietary behavior change on dietary and nutrient intakes. A particular benefit of the 2015-2020 DGA has been its focus on dietary patterns instead of individual nutrients, consistent with the way in which we typically eat; the Academy strongly encourages the DGAC to continue this focus in its present task.
C. Nutrition as a Biological Variable
The Academy strongly encourages the DGAC to conduct its evidence reviews and analysis and make its recommendations considering nutrition as a biological variable and treating it from a systems approach, including how nutrients interact with biological systems and the consideration of nutritional status as both an input and an outcome. Consideration must be given to the impact of substitution and realizing the larger impact of reductions or additions to one's diet.
Daniel J. Raiten, PhD, the Nutrition Program Director at the National Institute of Health's Eunice Kennedy Shriver National Institute of Child Health and Human Development, outlined the meaning of nutrition as a biological variable:
- An effort to improve the credibility of nutrition as a scientific discipline
- A more effective integration of nutrition (not just food/diet) in all aspects of biomedical research and by extension to efforts to promote health, prevent and treat disease
- An effort to provide new tools and approaches to support the constituencies involved in nutrition related research
- An acknowledgement of the importance of interdisciplinary research at all levels (basic, clinical, translational).34
Dr. Raiten notes that "contemporary nutrition questions concern health effects of marginal nutrient status more than those of acute deficiency" and that "[k]nowing an individual's nutrient status reveals little about function or effect."35 Of particular importance is the manner in which drugs and toxins and nutrients mutually affect one another and the "[i]nterrelationships of multiple nutrients in systems regulating drug metabolism."36
D. Quality of Nutrition Research
Despite what some critics of nutritional epidemiology assert, there is significant value in this research. The Academy recognizes that—as in every field—there are certain poorly designed studies, including some epidemiological and intervention studies, in this case by individuals without sufficient training in nutrition. These studies have inherent errors in unfounded or inaccurate assumptions as well as misuse of data because of a lack of understanding of nutrition science. Unfortunately, these errors can help create a body of literature that produces poor quality and often contradictory findings. We believe the literature not only needs to be evaluated based on the outcomes, but also culled for any poor quality designs that impede progress of dietary patterns research.
We reiterate, however, that these issues do not render nutrition epidemiology without value; in fact, the truth is quite the contrary. Observational data provides a unique perspective on the daily lives of thousands of Americans that would simply not be available in a timely or cost-effective manner from traditional clinical trials. We note that many of the same methods applied to dietary surveillance today were applied in the past to successfully identify smoking as a cause of lung cancer and a significant public health hazard.37 Although there are limitations to observational data, many of the specific criticisms leveled against NHANES and other data—particularly that underreporting in dietary assessments undermines the validity of the data—have been assuaged when the criticisms are analyzed in detail. Criticisms of NHANES have been found to be exaggerated, based on flawed methodologies, and awash in conflicts of interest.38 Underreporting is also unlikely to interfere with the use of findings from NHANES data to support the DGAC conclusions. In fact, underreporting would most likely serve the bias findings towards the null hypothesis and smaller effect sizes, thereby causing estimates and conclusions to be more conservative.39 When controlled trials are not available or when other research is not yet available, well-designed and sound nutrition epidemiology provides a solid foundation for dietary recommendations and forms the basis of driving dietary interventions. This issue again provides the rationale for fundamentally necessary USDA and NIH funding streams designed to address systemic gaps in the DGAs over time. Fundamental nutrition research questions on dietary patterns, nutrient needs for individuals in different life cycle stages and metabolic status, implementation barriers, and health inequity continue to exist and need to be addressed in a non-biased, rigorous manner. Collaborating with nutrition organizations and universities to get these questions answered is essential to improving the health of the U.S. population.
E. Structural Differences
There are significant structural differences between nutrition science and other disciplines. As one researcher notes, "there are many challenges and considerations unique to the field, such as the baseline nutritional status of study participants, defining appropriate control groups, effective blinding of participants and investigators, the evolving ethics of randomized control trials, and a tension in a priori decisions regarding inclusion of nutritionally vulnerable participants versus representative samples of general populations."40,41
The DGAs "provide guidance for choosing a healthy diet and focus on preventing the diet-related chronic diseases."42 The current funding environment allows limited exploration of the long term impacts of dietary intakes, let alone the monitoring of long term effects of nutrition intervention.
Institutional Review Board (IRB) approval and requirements are particularly difficult for nutrition research, and there are substantial ethical issues with randomized controlled trials (RCTs) on individuals for standard of care intervention including difficulty "blinding" the participants for many research trials not focused on dietary supplementation. As Weaver et al write, "deliberately depleting participants in a nutrient to the point of harm—or even to the point of biochemical impairment without overt clinical or physiological consequence—is now typically considered unacceptable. In recent years, IRBs have extended this ethical concept to RCTs in which deficiency is not being induced by the study protocol per se but a portion or all of the study population is low or deficient in a specific nutrient at baseline based on their own selected dietary patterns or other circumstances."43
There remains within nutrition research a lack of standardized and validated measures for some diet-related outcomes, a need for better nutrition standardized terminology and common data elements for research, and a need for additional funding. Securing funding for lifestyle behavior research, especially for prevention, is embattled by the sentiment of "don't we know nutrition is important for health" and the perceived likelihood of success compared to interventions based on supplementation. Funding is particularly critical given many researchers noting an insufficient ability to fund or cultivate interest research to confirm prior findings. Furthermore, Dr. Raiten also notes that, "A disconnect often exists between basic nutrition science and its translation to clinical research. This results, in part, from use or lack of relevant animal/experimental models and diets."44
In addition to the limited evidence in certain topics, challenges also come when designing and conducting research in nutrition science. Due to the nature, it is difficult to conduct double-blind, randomized placebo-controlled trials, which most considered as gold standard, for some topics. Thus when conducting systematic studies, non-RCT nutrition studies may be "marked down" in quality or seems weaker compared to drug trials. However, strong recommendations can come from a seemingly lower quality body of evidence. Many nutrients have multiple tissue or metabolic targets and thus a singular focus on one outcome may not demonstrate the whole impact of a nutrient (e.g., with respect to vitamin D, focusing on only one outcome, such as bone density, provides a limited view of the entirety of functions that vitamin D performs in the body. A more wholistic approach to nutrients and foods in general is needed. The use of composite outcomes maybe of use but we recognize the need for more research in this area.
III. Research Issues Specific to the Dietary Guidelines
A. Assumptions and Methodologies
We strongly encourage the DGAC to detail in an ongoing manner its relevant assumptions and methodologies in lay language. To that end, we appreciate the recent updates to the dietaryguidelines.gov website detailing the methodology used and noting the status and current stage of each respective process. Published protocols should provide sufficient detail to enable independent replication; at present, they do not. In addition, going forward, it is imperative for the DGAC to explain the reason for any deviation from the protocols as presented.
We are concerned about the impact of artificial, arbitrary time constraints on the systematic review process. At the first public meeting of the DGAC held March 28, 2019, Dr. Obbagy's presentation, Nutrition Evidence Systematic Review, stated, "Due to time and resource constraints, NESR will not be conducting systematic reviews with input from technical expert panels, rather NESR will be conducting systematic reviews directly with the 2020 Committee."45 At the second public meeting, the public was informed of the Departments' intentions to complete the work of the DGAC by May of 2020, approximately five months earlier than anticipated in the DGAC's charter. Critical work of developing systematic reviews should not sacrifice quality for alacrity, nor should they be developed in a manner that is less-transparent or that engages fewer relevant experts than was previously used. The Dietary Guidelines for Americans are simply too important to be rushed unnecessarily. Rather than arbitrarily cutting short the process, the Departments could provide additional support through a contracting process that ensures transparency and alignment with consistent methodologies.
B. Proposed Protocols
1. Dietary Patterns
The Academy has reviewed the available search protocol on dietary patterns and all-cause mortality. The 'intervention/exposure' coined as 'dietary pattern' will likely be common for all the relationships explored under this topic and subcommittee. Thus, it will be important to carefully and explicitly define the concept 'dietary pattern'. As described, it is not explicit that known patterns such as (1) Diet, Western; (2) Diet, Mediterranean; (3) Diet, Vegetarian and (4) others will be consistently searched for. We believe it is important to define what exactly each diet means (e.g., is a high-fat diet predicated upon a percentage of fat in the diet, or is the type of fat in the diet relevant to the definition?).
We recommend an explicit listing of specific search terms listed in the protocols, at minimum terms that are MeshTerms in PubMed, to ensure reproducibility of the searches. As presented, key areas may not be addressed, or searches may not be consistent across this group of relationships on all search protocols, including dietary patterns.
2. Sources of Saturated Fat
Overall the protocol for sources of saturated fat appears appropriate. However, we encourage the DGAC to ensure that "total amount of saturated fat intake" is collected and taken into consideration when writing conclusions.
3. Specific Nutrients from Supplements and/or Fortified Foods
If research is available, we believe it would be appropriate and beneficial to differentiate the studies that used supplement from natural nutrients (i.e., whole food sources) as opposed to synthetic nutrients.
4. Frequency of Eating
The Academy shares concerns raised by DGAC members at the second public meeting suggesting that simply drinking water would be considered an "eating occasion" for the frequency of eating protocols. The DGAC should ensure it can reconcile this proposed definition with traditional understandings and concepts of fasting for religious and other purposes. In addition, we note it is not unusual for individuals to eat lunch and dinner eight hours or more apart, whether because work continues into the evening or as consistent with cultural traditions. The use of NHANES for dietary patterns analyses allows for less researcher bias by allowing the participant to define the meal or eating occasion. This adds content and face validity to the DGA recommendations anchored to meal intake patterns. Further, lifestyle and financial barriers, such as food insecurity, may lead individuals to delay eating for eight hours or more at a time. The definition of fasting should account for these experiences and recognize the intentional nature of fasting rather than as a habitual or forced schedule.
C. Target Population Issues
As noted above, the charter for the 2020 DGAC reminds us that the National Nutrition Monitoring and Related Research Act of 1990 (Section 301 of Public Law 101-445 codified at 7 U.S.C. 5341) instructs that [the DGAs] shall contain nutritional and dietary information and guidelines for the general public."46 This creates a significant tension when the general public has obesity, overweight, or one or more other chronic diseases. The DGAC must make clear if and when its dietary recommendations are appropriate for (1) a general population in which more than two-thirds of the adult population is overweight or instead (2) prevention for obesity and other chronic diseases.
If there are differences in recommendations for preventing disease among a healthy population and preventing or managing disease among a population with one or more chronic diseases or risk factors for them, the DGAC should explicitly ascertain those differences when evaluating the existing science and make explicit the populations for which it is making recommendations. A different set of literature is needed for disease treatment and health promotion. In addition, the DGAC should make clear whether recommendations are based upon the concepts leading to, and inherent in, the new Chronic Disease Risk Reduction Intake (CDRR) category outlined in the recent National Academies' report, Dietary Reference Intakes for Sodium and Potassium.47 We seek clarification as to the extent to which specific recommendations may rely on DRIs that are outdated, overly reliant upon surrogate endpoints, or otherwise ripe for an update.
To promote understanding of the Scientific Report and the subsequent Guidelines, we encourage the DGAC to reiterate that the DGAs don't apply to people with certain health statuses and are not meant to replace medical advice or individualized recommendations based on health assessment and disease status. In addition, recommendations may differ across the lifecycle—particularly for older adults—making the current age-related approach appropriate. In short, the DGAs should indicate when certain recommendations may differ for a significant proportion of Americans, and should explicitly detail its rationale for making differing recommendations.
D. Peer Review of Systematic ReviewsThe Academy is pleased that, "All systematic reviews conducted by the 2020 Committee will undergo a formal peer review process coordinated by the USDA Agricultural Research Service (ARS)."48 We look forward to the Departments detailing specifics of this peer review process in advance of the ARS conducting it. It is critical that the scientific community is able to have confidence in the peer review process and be assured that it provides an appropriate, scientifically-sound method for research validation devoid of outside, non-scientific interference.
We encourage the Departments and the DGAC to identify how peer review can be better integrated into the timeline, recognizing that peer review may need to happen at multiple timepoints rather than just once in the systematic review process. In addition, we seek clarification as to how the methods of external systematic reviews used to inform the Scientific Report will be vetted. Finally, it is essential that the DGAs themselves be peer reviewed before they are finalized to ensure compliance with the requirements of the National Nutrition Monitoring and Related Research Act of 1990 that the DGAs "shall be based on the preponderance of the scientific and medical knowledge which is current at the time the report is prepared." This necessary aspect of peer review would appropriately occur after the Departments incorporate any suggested changes resulting from congressional oversight or political persuasion.
E. Scientific Reviews and Food Pattern Modeling
The Academy respectfully requests that the DGAC specify which recommendation statements are based on systematic reviews, which are based on food pattern modeling analyses, and which are based upon a combination thereof. The underlying assumptions and targets of the models will need to be explicitly described from the models. This includes how foods and food groups are evaluated (most commonly consumed vs variety of foods) and if the endpoints target food group intakes or meeting nutrient intake recommendations. When developing public health and clinical guideline recommendations, the DGA scientific committee should use gold standard methods. As such, identification of the type and strength of evidence used to shape the DGA recommendations would enhance their credibility through transparency. The GRADE method is evolving to include subspecialties that have unique challenges limiting their use of RCTs and specifically the GRADE tables could be used to demonstrate the evidence used to shape the DGA recommendations.
F. Consideration of Non-Public Data
We note that Cochrane systematic reviews sometimes include results from studies that are not yet published. We query whether the Departments and the DGAC will engage with researchers to incorporate these ongoing trials into the systematic reviews guiding the DGAs.
IV. Additional Issues for DGAC and the Departments' Consideration
1. National Academies' Recommendations
Implementation of the DGA by the US population is difficult or impossible if healthy food choices are not accessible with an individual's environment. Increasing accessibility to health food choices involves a systems approach that expands from food growth and procurement to sales and ensures that the healthy food is physically and financially available to the majority of the population. The US population cannot fully adopt or implement the guideline recommendations if the foods are unavailable. For example, there are currently available insufficient fruits and vegetables necessary for every American to adopt the current fruit and vegetable recommendations. Including sustainability in the DGA targets this identified-need for enhanced access to a healthy food supply.
The Academy has long supported the Departments' implementation of the National Academies recommendations to improve the DGA development process. As part of the ongoing process of implementation, we specifically highlight the National Academies' recommendation that
Encouraging adoption of the DGA could be facilitated by including topics of importance to the general public through established methods[, such as] surveys. . . . To develop guidelines that people can follow, it will be important to turn the DGA recommendations into practical advice to help consumers make decisions in the marketplace.49
Indeed, such surveys have already been conducted, including one "by Greenberg Quinlan Rosner Research[ that] polled 800 Americans and found an interest in sustainability measures that cuts across partisan political lines. Nearly 83% of Democrats, 72% of Independents, and 64% of Republicans agree that the dietary guidelines should take into account environmental considerations as they relate to health, nutrition, and long-term healthy food availability."50> In total, "[n]early three-quarters of adults surveyed believe U.S. Dietary Guidelines should include environmental provisions and support sustainable agriculture practices."51 However, these recommendations need to be based on valid and rigorous scientific outcomes as expected for all recommendations from the DGAs. To implement the National Academies' recommendations, the role of sustainability must be considered for each of the relevant identified topics.
2. Departments' Existing Resources and Authority
We recognize that the Departments have specified that, "The Committee will limit its review and advice to dietary guidance for human nutrition on the topics and scientific questions specified by the Departments."52 Pursuant to its charter, the DGAC "will provide its advice and recommendations to the USDA Under Secretaries of Food, Nutrition, and Consumer Services (FNCS) and Research, Education, and Economics (REE) and HHS Assistant Secretary for Health."53 Dr. Scott Hutchins, the Deputy Under Secretary for Research, Education, and Economics, oversees both USDA's Economic Research Service (ERS) and NIFA, which have together compiled substantial research and drawn conclusions regarding the association of sustainability, climate change, food, and nutrition. Given the importance Dr. Hutchins' own agencies ascribe to sustainability's connection to human nutrition and food, we presume it will incorporate these findings into the 2020-2025 DGAs irrespective of its decision not to "seek advice to be examined by the Committee."54
Even if a topic is addressed through existing evidence-based federal guidance or in ERS and NIFA studies but is not addressed by the Committee, we believe it must be included in the DGA if it can help guide individual consumers or institutional policies towards healthier diets or ensure federal policies align with relevant science. If key topics are omitted, there will be significant gaps in evidence-based federal guidance for food and nutrition. Therefore, the 2020-2025 DGA should encompass all of the federal government's evidence on sustainability and other dietary practices for optimal nutrition and food policies, "including new scientific evidence and current resource documents."55
The Academy is familiar with the growing body of evidence around the importance of sustainable practices in food and water systems, including the alarming amount of food wasted daily in the United States, which the ARS estimates per capita at 1,249 calories per day.56 Food wasted on a daily basis could provide substantial amounts of the recommended intake of nutrients identified as shortfall nutrients in the 2015-2020 DGAs, including iron for 66% of the population, calcium for 40% of the population, and fiber for 27% of the population.57 Registered dietitian nutritionists recognize the opportunity and responsibility, as food and nutrition professionals, to integrate the principles of sustainable, resilient, and healthy food and water systems into our respective practice areas as a means to secure, preserve, and strengthen these systems now and for the future. The Academy continues to develop and implement standards of professional performance for practitioners in the area of sustainable, resilient, and healthy food and water systems to ensure that we can better serve our clients and communities now and in the future.58
A growing body of literature raises important questions about our collective ability to meet human nutritional needs given the finite natural resource available to us. One of many such reports is the EAT/Lancet Commission, which recommends that dietary patterns should be viewed not only on the basis of their ability to promote health outcomes, but also on the basis of their ability to mitigate environmental externalities and their alignment with global agendas such as the United Nations Sustainable Development Goals.59 The Academy encourages the Departments to review several scientific questions for the proposed sustainability topic, recognizing the questions are also relevant to food insecurity and other cross-cutting issues:
- What is our nation's capacity to supply, consistently and equitably across regions, the foods recommended by the proposed dietary pattern(s)? If that supply is insufficient or inequitably distributed, what (if any) shifts in agricultural production (i.e., what is produced and how) and policy would be needed to ensure sufficient supply of the recommended foods or food groups? For example, the DGAs generally recommend increased consumption of seafood and fruits & vegetables (above the current levels of typical consumption), but the US seafood supply only provides enough seafood to meet about half of this demand, and only 55% of the global population lives in countries where fruit and vegetable availability surpasses minimum targets for consumption.60,62 This underscores the need to take into account the natural resource constraints that may undermine our ability to meet dietary recommendations now and in the future.
- Do the proposed shifts in consumption patterns to address environmental sustainability meet the nutritional needs of Americans? This includes the composition of amino acids and fatty acids, as well as the quantity and bioavailability of micronutrients to support optimal nutritional status.
- Are U.S. households of varying income levels able to afford the proposed dietary patterns, and what is the likelihood of long-term adherence to the proposed dietary pattern(s) in light of potential economic barrier? In addition, the DGAC should assess what, if any, geographic or demographic disparities exist in households' ability to afford adherence to such a pattern.
- If financial or geographic access to and intake of such foods is inequitable, what evidence-based programs and policies (e.g., based on experiences and experiments at the local, state and regional levels) could be tested or scaled nationally to reduce such disparities and bolster implementation of and adherence to the Guidelines?
- Evaluate the estimated economic impact (e.g., on our agricultural economy) and ecological impact of collective adherence to the Guidelines and of any shifts in production needed to better support the proposed dietary pattern(s).
B. Dissemination and Implementation Resources
The National Academies estimates that "less than 10% of Americans actually follow the Guidelines."62 Despite the strength of the recommendations and the evidence underlying them, the Guidelines cannot meet their promise without substantially more widespread and effective implementation and dissemination. We agree with the National Academies that, "The transfer of knowledge from science-based recommendations into actionable guidance that may be adopted by the general public can be challenging. An intentional effort to do so is warranted and should be guided by models that deploy proven processes."63 As noted above, we seek clarification whether the DGAC and/or the Departments will utilize a systematic and transparent process for translating evidence to guidelines. In addition, the Departments should engage a broad group of stakeholders to help translate the guidelines into action and implementation in an effective way.
Implementation science is relatively new but shows significant promise in its value, and thus we encourage the DGAC to give considerable consideration to improving strategies for implementation of the Guidelines in the 2020-2025 iteration. In addition, we seek ongoing updates on the DGAC's plans for dissemination.
Effective implementation likely includes tailoring of the implementation strategies to the contextual needs of a particular change effort. The Academy encourages the DGAC to assess the ability of various subgroups of the population to effectively implement the Guidelines in their own lives, including those with chronic illness, struggles with hunger and food insecurity, and other impediments. Effective implementation of the DGAs require that the Guidelines themselves recognize the functional reality that health inequities, existing chronic health conditions, and the socio-economic status and environmental conditions of many Americans greatly limits their opportunities to incorporate the DGAs into their lifestyle.
The Academy welcomes a scientific review of strategies to help best facilitate the adoption or selection of healthy dietary patterns among Americans. We encourage the DGAC to review the extent to which successful implementation of dietary recommendations depends upon how referenced dietary patterns are interpreted by various subpopulations and the referenced diets or eating styles those subpopulations adopt.
Finally, we recognize the increasing interest in personalized and individualized nutrition and the growing body of research in this field. Although the prospects are presently limited, we are excited at the future potential for guidelines that could apply to the general public as the law requires, taking into account genetic, epigenetic, cultural, and other differences.
We urge the Departments and the DGAC to consider what tools are offered to support acceptance and adoption of the Guidelines. For example, USDA discontinued Supertracker in 2018 without replacement with the explanation that was too much overlap with existing private resources (e.g., websites and mobile apps available for tracking food, activity and weight). However, not only are these private resources not available at non-charge (as Supertracker was, thereby creating inequity for individuals with low socio-economic status), they do not necessarily meet disability accessibility guidelines, and there is no assurance whatsoever they are either accurate or work to reinforce the DGA messages.
Pursuant to the charter filed October 5, 2018, "The Committee is established to accomplish a single, time-limited task. It is expected that the Committee will complete the objectives for which it was established within two years from the date this charter is filed." We strongly urge the DGAC to utilize the entire two years for which it is authorized to conduct evidence reviews, analyze the results, consider its recommendations, and draft its scientific report. The DGAC has been tasked this iteration with drafting not just the scientific report similar to that which previous DGACs drafted, but in addition, has been tasked with drafting a wholly new scientific report for a new population: children from birth to 24 months. Given this additional work and the overall importance of the DGA development process, we see no reason to sacrifice quality for expediency; there is no reason why the DGAC needs to complete its work to meet an arbitrary and artificial deadline and should instead complete its work accordance with the charter in October 2020.
The Academy appreciates the opportunity to comment on the evidence analysis process and other issues of concern for the DGAC. We are happy to discuss these recommendations in greater detail in the near future. Please contact either Alison Steiber at 202/775-8277 ext. 4860 or by email at firstname.lastname@example.org or Pepin Tuma at 202/775-8277 ext. 6001 or by email at email@example.com with any questions or requests for additional information.
Alison Steiber, PhD, RDN
Chief Science Officer
Academy of Nutrition and Dietetics
Pepin Andrew Tuma, Esq.
Sr Director, Government & Regulatory Affairs
Academy of Nutrition and Dietetics
Members of the Academy of Nutrition and Dietetics' Collaborative on the DGAs
Catherine Champagne, PhD, MS, RDN, LDN, FADA, FAND
Louisiana State University Pennington Biomedical Research Center
Alana Cline, PhD, RD
University of Northern Colorado (retired)
Patricia Davidson, DCN, RDN, CDE, LDN, FAND
West Chester University
Sharon Groh-Wargo, PhD, RD, LD
Case Western Reserve University School of Medicine
Deanna M. Hoelscher, PhD, RDN, LD, CNS, FISBNPA
University of Texas Health Science Center at Houston School of Public Health in Austin
Teresa A. Marshall, PhD, RDN
University of Iowa College of Dentistry
Punam Ohri-Vachaspati, PhD, RD, LD
Arizona State University College of Health Solutions
Hollie Raynor, PhD, RD, LDN
University of Tennessee Knoxville
Diane L. Rigassio-Radler, PhD, RDN<
Rutgers, The State University of New Jersey
Kim Robien, PhD, RD, FAND
Milken Institute School of Public Health at George Washington University
Joanne L. Slavin, PhD, RD<
University of Minnesota
Marie Spiker, PhD, MSPH, RDN
Healthy and Sustainable Food Systems Fellow, Academy of Nutrition and Dietetics Foundation
Mary Story, PhD, RD
Duke Global Health Institute
Christopher A. Taylor, PhD, RDN, LD, FAND (Chairman)
The Ohio State University
Brie Turner-McGrievy, PhD, MS, RD, FTOS
University of South Carolina Arnold School of Public Health
1 United States Department of Agriculture. Charter for the 2020 Dietary Guidelines Advisory Committee, Section 4 p.2. Available at https://www.dietaryguidelines.gov/sites/default/files/2019
2 Ibid., Section 3, p.1.
3 U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition, Introduction at p.6. December 2015. Available at https://health.gov/dietaryguidelines/2015/guidelines/. Accessed July 6, 2019.
5 Fryar CD, Carroll MD, Ogden CL. Prevalence of overweight, obesity, and extreme obesity among adults aged 20 and over. National Center for Health Statistics. 2016 July. Available athttps://www.cdc.gov/nchs/data/hestat/obesity_adult_13_14/obesity_adult_13_14.htm. Accessed July 10, 2019.
6 Centers for Disease Control and Prevention. A Snapshot: Diabetes in the United States. 2017 November. Available at https://www.cdc.gov/diabetes/library/socialMedia/infographics.html. Accessed July 10, 2019.
7 Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/ PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2017 Nov 7. pii: S0735-1097(17)41519-1. doi: 10.1016/j.jacc.2017.11.006.
8 Centers for Disease Control and Prevention. Cancers Associated with Overweight and Obesity Make up 40% of Cancers Diagnosed in the United States. 2017 October. Available at https://www.cdc.gov/media/releases/2017/p1003-vs-cancer-obesity.html. Accessed July 10, 2019.
9 Buttorff C. Multiple Chronic Conditions in the United States. 2017. Available at http://www.fightchronicdisease.org/sites/default/files/TL221_final.pdf. Accessed July 6, 2019.
10 See, e.g., Center on the Developing Child at Harvard University (2010). The Foundations of Lifelong Health Are Built in Early Childhood. Available at http://www.developingchild.harvard.edu. Accessed July 10, 2019.
11 Mcmillen IC, Adam CL, Mühlhäusler BS. Early origins of obesity: programming the appetite regulatory system. J Physiol (Lond). 2005;565(Pt 1):9-17.
12 Borja JB. The impact of early nutrition on health: key findings from the Cebu Longitudinal Health and Nutrition Survey (CLHNS). Malays J Nutr. 2013;19(1):1-8.
13 Secretary of Health and Human Services. Charter: 2015 Dietary Guidelines Advisory Committee. Washington, DC: 2013, section 3, p.1. Available at https://health.gov/dietaryguidelines/dgac2015-charter-final.pdf. Accessed July 6, 2019. (Emphasis added.)
14 U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition, Introduction at p.5. December 2015. Available at https://health.gov/dietaryguidelines/2015/guidelines/. Accessed July 6, 2019. (Emphasis added.)
15 Myers EF, Khoo CS, Murphy W, Steiber A, Agarwal S. A critical assessment of research needs identified by the dietary guidelines committees from 1980 to 2010. J Acad Nutr Diet. 2013;113(7):957-971.e1.
16 Vaccaro JA, Huffman FG. Sex and Race/Ethnic Disparities in Food Security and Chronic Diseases in U.S. Older Adults. Gerontol Geriatr Med. 2017;3:2333721417718344. Published 2017 Jun 30. doi:10.1177/2333721417718344 ("Although the national average of household food insecurity is 14%, it is 22.4% for Hispanic households and 26% for African American households as compared with 11% for White non-Hispanics." (Internal citations omitted.)).
17 Liang Wang, Jodi Southerland, Kesheng Wang, et al., "Ethnic Differences in Risk Factors for Obesity among Adults in California, the United States," Journal of Obesity, vol. 2017, Article ID 2427483, 10 pages, 2017. https://doi.org/10.1155/2017/2427483.
18 NEW Soul. Nutritious Eating with Soul Study. Available at https://www.newsould.org. Accessed July 30, 2019.
19 Ritchie, L. D., Woodward‐Lopez, G., Au, L. E., Loria, C. M., Collie‐Akers, V., Wilson, D. K., Frongillo, E. A.,Strauss, W. J., Landgraf, A. J., Nagaraja, J., Sagatov, R. D. F., Nicastro, H. L., Nebeling, L. C., Webb, K. L., and on behalf of the Healthy Communities Study Team ( 2018) Associations of community programs and policies with children's dietary intakes: the Healthy Communities Study. Pediatric Obesity, 13: 14– 26. https://doi.org/10.1111/ijpo.12440.
20 NASEM 2 at 43.
21 National Academies of Sciences, Engineering, and Medicine. 2017. Redesigning the process for establishing the Dietary Guidelines for Americans. Washington, DC: The National Academies Press. doi: https://doi.org/10.17226/24883 (NASEM 2) at 129.
22 National Nutrition Monitoring and Related Research Act of 1990 (Public Law 101-445 - Oct. 22, 1990).
23 NASEM 2 at 129.
24 NASEM 2 at 43.
25 U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition, Message from the Secretaries at vii. December 2015. Available at https://health.gov/dietaryguidelines/2015/guidelines/. Accessed July 6, 2019.
26 Wood-Wright, Natalie. "New U.S. dietary guidelines ignore broad support for food sustainability." Hub, Johns Hopkins University, Mar 11, 2016, https://hub.jhu.edu/2016/03/11/dietary-guidelines-sustainability-survey/.
27 Cutberto Garza, Patrick J Stover, Sarah D Ohlhorst, Martha S Field, Robert Steinbrook, Sylvia Rowe, Catherine Woteki, Eric Campbell, Best practices in nutrition science to earn and keep the public's trust, The American Journal of Clinical Nutrition, Volume 109, Issue 1, January 2019, Pages 225–243, https://doi.org/10.1093/ajcn/nqy337.
28 Polman, J. L., Newman, A., Saul, E. W. & Farrar, C. (2014). Adapting practices of science journalism to foster science literacy. Science Education, 98(5), 766-791. doi: 10.1002/sce.21114 P. 10
30 See, e.g., Rothman RL, Housam R, Weiss H, et al. Patient understanding of food labels: the role of literacy and numeracy. Am J Prev Med. 2006;31(5):391-8. See also, Speirs KE, Messina LA, Munger AL, Grutzmacher SK. Health literacy and nutrition behaviors among low-income adults. J Health Care Poor Underserved. 2012;23(3):1082-91.
31 Thomas H, Azevedo Perry E, Slack J, et al. Complexities in Conceptualizing and Measuring Food Literacy. J Acad Nutr Diet. 2019;119(4):563-573 (internal citations omitted).
32 Scientific Report of the 2015 Dietary Guidelines Advisory Committee (DGAC Report). Part D. Chapter 3, Page 25. Dietary Guidelines website. Released February 23, 2015. Accessed July 8, 2019.
33 Nutrition Evidence Library. "A Series of Systematic Reviews on the Relationship Between Dietary Patterns and Health Outcomes." United States Department of Agriculture. 2014. Accessed April 28, 2015. Nutrition Evidence Library. "2015 DGAC Dietary Patterns NEL Systematic Reviews" United States Department of Agriculture. 2015. Accessed April 28, 2015.
34 Raiten, Daniel J. "Nutrition as a Biological Variable (NABV): Integrating Nutrition into Basic and Clinical Research and Care; A Conceptual Framework." Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 2017, http://ilsi.eu/wp-content/uploads/sites/3/2017/04/Dr-Daniel-Raiten.pdf.
37 Proctor, R. N. (2012). The history of the discovery of the cigarette–lung cancer link: evidentiary traditions, corporate denial, global toll. Tobacco control, 21(2), 87-91.
38 Archer, E., Hand, G. A., & Blair, S. N. (2013). Validity of US nutritional surveillance: National Health and Nutrition Examination Survey caloric energy intake data, 1971–2010. PloS one, 8(10), e76632. Compare to Healthy People 2020. PA-2. Increase the proportion of adults who meet current federal physical activity guidelines for aerobic physical activity and for muscle-strengthening activity. Washington, DC: U.S. Department of Health and Human Services. Office of Disease Prevention and Health Promotion; [cited 2014]. Available from: https://www.healthypeople.gov/2020/topics-objectives/topic/physical-activity/objectives.
39 Jepsen P, Johnsen SP, Gillman MW, Sørensen HT. Interpretation of observational studies. Heart. 2004;90(8):956-960. doi:10.1136/hrt.2003.017269.
40 Connie M Weaver, Joshua W Miller, Challenges in conducting clinical nutrition research, Nutrition Reviews, Volume 75, Issue 7, July 2017, Pages 491–499, https://doi.org/10.1093/nutrit/nux026
41 Hébert JR, Frongillo EA, Adams SA, et al. Perspective: Randomized Controlled Trials Are Not a Panacea for Diet-Related Research. Adv Nutr. 2016;7(3):423–432. Published 2016 May 16. doi:10.3945/an.115.011023
42 2015-2020 Dietary Guidelines for Americans — Page vii
43 Connie M Weaver, Joshua W Miller, Challenges in conducting clinical nutrition research, Nutrition Reviews, Volume 75, Issue 7, July 2017, Pages 491–499, https://doi.org/10.1093/nutrit/nux026
44 Raiten, Daniel J. "Nutrition as a Biological Variable (NABV): Integrating Nutrition into Basic and Clinical Research and Care; A Conceptual Framework." Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 2017, http://ilsi.eu/wp-content/uploads/sites/3/2017/04/Dr-Daniel-Raiten.pdf.
45 Obbagy, Julie. "Nutrition Evidence Systematic Review Presentation." Dietary Guidelines for Americans website, March 28, 2019. Accessed at https://www.dietaryguidelines.gov/day-1-nutrition-evidence-systematic-review.
46 United States Department of Agriculture. Charter for the 2020 Dietary Guidelines Advisory Committee, Section 3 p.1. Available at https://www.dietaryguidelines.gov/sites/default/files/2019-03/DietaryGuidelinesAdvisoryCommitteeCharter-10-05-18.pdf. Accessed July 6, 2019. (Emphasis added.)
47 National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for sodium and potassium. Washington, DC: The National Academies Press. doi: https://doi.org/10.17226/25353
48 Obbagy, Julie. "Nutrition Evidence Systematic Review Presentation." Dietary Guidelines for Americans website, March 28, 2019. Accessed at https://www.dietaryguidelines.gov/day-1-nutrition-evidence-systematic-review.
49 NASEM 2 at 45.
50 Wood-Wright, Natalie. "New U.S. dietary guidelines ignore broad support for food sustainability." Hub, Johns Hopkins University, Mar 11, 2016, https://hub.jhu.edu/2016/03/11/dietary-guidelines-sustainability-survey/.
52 United States Department of Agriculture. Charter for the 2020 Dietary Guidelines Advisory Committee. Available at https://www.dietaryguidelines.gov/sites/default/files/2019-03/DietaryGuidelinesAdvisoryCommitteeCharter-10-05-18.pdf. Accessed July 6, 2019.
56 Buzby, Jean C., Hodan F. Wells, and Jeffrey Hyman. The Estimated Amount, Value, and Calories of Postharvest Food Losses at the Retail and Consumer Levels in the United States, EIB-121, U.S. Department of Agriculture, Economic Research Service, February 2014.
57 Spiker ML, Hiza HAB, Siddiqi SM, Neff RA. Wasted Food, Wasted Nutrients: Nutrient Loss from Wasted Food in the United States and Comparison to Gaps in Dietary Intake. J Acad Nutr Diet. 2017;117(7):1031-1040.e22.
58 Tagtow A, Robien K, Bergquist E, et al. Academy of Nutrition and Dietetics: Standards of professional performance for Registered Dietitian Nutritionists (Competent, Proficient, and Expert) in Sustainable, Resilient, and Healthy Food and Water Systems. J Acad Nutr Diet. 2014;114(3):475-488.e24.
59 Willett, W., Rockström, J., Loken, B., Springmann, M., et.al. 2019. Food in the Anthropocene: the EAT–Lancet Commission on healthy diets from sustainable food systems. EAT-Lancet EAT–Lancet Commission on healthy diets from sustainable food systems DOI: 10.1016/S0140-6736(18)31788-4.
60 C. Love, Dave & Fry, Jillian & C. Milli, Michael & Neff, Roni. (2015). Wasted seafood in the United States: Quantifying loss from production to consumption and moving toward solutions. Global Environmental Change. 35. 116-124. 10.1016/j.gloenvcha.2015.08.013.
61 Mason-D'Croz, Daniel & R Bogard, Jessica & Sulser, Timothy & Cenacchi, Nicola & Dunston, Shahnila & Herrero, Mario & Wiebe, Keith. (2019). Gaps between fruit and vegetable production, demand, and recommended consumption at global and national levels: an integrated modelling study. 3. e318-e329. 10.1016/S2542-5196(19)30095-6.
62 NASEM 2 at ix.
63 NASEM 2 at 43.