Scientific Report of the 2015 Dietary Guidelines Advisory Committee

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Part D. Chapter 1: Food and Nutrient Intakes, and Health: Current Status and Trends - Continued

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List of Questions

Nutrient Intake and Nutrients of Concern

  1. What are current consumption patterns of nutrients from foods and beverages by the U.S. population?
  2. Of the nutrients that are underconsumed or overconsumed, including over the Tolerable Upper Limit of Intake (UL), which present a substantial public health concern?
    1. What would be the effect on food choices and overall nutrient adequacy of limiting saturated fatty acids to 6 percent of total calories by substituting mono- and polyunsaturated fatty acids?
  3. Is there evidence of overconsumption of any micronutrients from consumption of fortified foods and supplements?
  4. What is the level of caffeine intake derived from foods and beverages on the basis of Institute of Medicine (IOM) Dietary Reference Intakes age and sex categories in the U.S. population?
  5. How well do updated USDA Food Patterns meet IOM Dietary Reference Intakes and 2010 Dietary Guidelines recommendations? How do the recommended amounts of food groups compare to current distributions of usual intakes for the U.S. population?
    1. How well do the USDA Food Patterns meet the nutritional needs of children 2 to 5 years of age and how do the recommended amounts compare to their current intakes? Given the relatively small empty calorie limit for this age group, how much flexibility is possible in food choices?
  6. Can vitamin D Estimated Average Requirements (EARs) and/or Recommended Dietary Allowances (RDAs) be met with careful food choices following recommended amounts from each food group in the USDA Food Patterns? How restricted would food choices be, and how much of the vitamin D would need to come from fortified dairy and other food products?

Food Groups—Current Intakes and Trends

  1. What are current consumption patterns of USDA Food Pattern food groups by the U.S. population?
    1. What is the contribution of whole grain foods, fruits and vegetables, and other food groups to (1) total fiber intake and (2) total nutrient intake in the USDA Food Patterns? What is the contribution of fruit and vegetables to current nutrient intake (focus on nutrients of concern, including fiber)?
    2. What would be the impact on the adequacy of the patterns if (1) no dairy foods were consumed, (2) if calcium was obtained from nondairy sources (including fortified foods), and (3) if the proportions of milk and yogurt to cheese were modified?  What is the relationship between changes in types of beverages consumed (milk compared with sugar-sweetened beverages) and diet quality?
  2. What are the trends in USDA Food Pattern food group consumption by the U.S. population?

Food Categories—Current Intakes and Sources of Energy, Nutrient, and Food Group Intakes

  1. What are the current consumption patterns by food categories (i.e., foods as consumed) by the U.S. population?
  2. What are the top foods contributing to energy intake by the U.S. population?
  3. What are the top foods contributing to sodium, saturated fat, and added sugars intake by the U.S. population?
    1. What is the current contribution of fruit products with added sugars to intake of added sugars?
    2. What is the current contribution of vegetable products with added sodium to intake of sodium?
    3. What is the current contribution of refined grains to intake of added sugars, saturated fat, some forms of polyunsaturated fat, and sodium?
    4. What are the sources of caffeine from foods and beverages on the basis of age and sex subgroups?
  4. What is the contribution of beverage types to energy intake by the U.S. population?

Eating Behaviors—Current Status and Trends

  1. What are the current status and trends in the number of daily eating occasions and frequency of meal skipping? How do diet quality and energy content vary based on eating occasion?
  2. What are the current status and trends in the location of meal and snack consumption and sources of food and beverages consumed at home and away from home? How do diet quality and energy content vary based on the food and beverage source?

Prevalence of Health Conditions and Trends

  1. What is the current prevalence of overweight/obesity and distribution of body weight, body mass index (BMI) and abdominal obesity in the U.S. population and in specific age, sex, race/ethnicity and income groups? What are the trends in prevalence?
  2. What is the relative prevalence of metabolic and cardiovascular risk factors (i.e., blood pressure, blood lipids, and diabetes) by BMI/waist circumference in the U.S. population and specific population groups?
  3. What are the current rates of nutrition-related health outcomes (i.e., incidence of and mortality from cancer [breast, lung, colorectal and prostate] and prevalence of cardiovascular disease (CVD), high blood pressure, diabetes, bone health, congenital anomalies, and neurological and psychological illness) in the overall U.S. population?

Dietary Patterns Composition

  1. What is the composition of dietary patterns with evidence of positive health outcomes (e.g., Mediterranean-style patterns, Dietary Approaches to Stop Hypertension (DASH)-style patterns, patterns that closely align with the Healthy Eating Index, and vegetarian patterns) and of patterns commonly consumed in the United States? What are the similarities (and differences) within and among the dietary patterns with evidence of positive health outcomes and the commonly consumed dietary patterns?
  2. To what extent does the U.S. population consume a dietary pattern that is similar to those observed to have positive health benefits (e.g., Mediterranean-style patterns, Dietary Approaches to Stop Hypertension (DASH)-style patterns, patterns that closely align with the Healthy Eating Index, and vegetarian patterns) overall and by age/sex and race/ethnic groups?
  3. Using the Food Pattern Modeling process, can healthy eating patterns for vegetarians and for those who want to follow a Mediterranean-style dietary pattern be developed? How do these patterns differ from the USDA Food Patterns previously updated for use by the 2015 DGAC?

Methodology

To address questions on the current status and trends in food and nutrient intakes, the prevalence of diet-related chronic diseases in the U.S. population, and the composition of healthful dietary patterns, the DGAC relied on analysis of data from several sources and food pattern modeling analyses. Many of the questions relied on analysis of data from What We Eat in America (WWEIA), the dietary component of the National Health and Nutrition Examination Survey (NHANES), using either existing data tables or new analyses conducted by the Data Analysis Team (DAT) upon request of the DGAC (see Part C. Methodology, Data Analyses section, and Appendix E-4: NHANES Data Used in DGAC Data Analyses). Existing data tables were used when available to answer questions about nutrient intake, food group intake, and meal and snack consumption. In some cases, new analyses were conducted by DAT agencies to provide additional information on food or nutrient intake, for example, by specific population groups, such as pregnant women, or information on potential overconsumption of nutrients when supplement intake is considered. New WWEIA/NHANES data analyses also were used to answer questions about food category intakes, the energy content and nutrient density of foods by point of purchase and location of consumption, and the food choices of self-identified vegetarians.

Data from the U.S. Centers for Disease Control and Prevention (CDC) NHANES data tables and from the peer-reviewed literature, also were the source of information on prevalence of health conditions, including body weight status, lipid profiles, high blood pressure, and diabetes. In addition, NHANES data on biochemical indicators of diet and nutrition in the U.S. population were used to help determine nutrients that may be of public health concern. To supplement data from NHANES, additional data sources were drawn upon to answer questions on the prevalence of health conditions, including the National Health Interview Survey, the National Cancer Institute’s Surveillance Epidemiology and End Results (SEER) cancer registry statistics, SEARCH for Diabetes in Youth Study (SEARCH), and heart disease and stroke statistics from the 2014 report of the American Heart Association.6

Some of the questions posed by the DGAC were best addressed by Food Pattern Modeling (see Part C. Methodology, Special Analyses Using the USDA Food Patterns section). These included questions about the nutrient adequacy of the USDA Food Patterns, modifications of the patterns for specific population groups or to meet specific nutrient targets, and the nutrients provided by various food groups in the Patterns. In some cases, questions could be answered with modeling analyses that had been conducted for the 2005 or 2010 DGACs, and so the results of these analyses were brought forward. The modeling process also was used to develop new USDA Food Patterns based on different types of evidence: Healthy Vegetarian Patterns that take into account food choices of self-identified vegetarians, and Healthy Mediterranean-style Patterns that take into account food group intakes from studies using a Med-diet index to assess dietary patterns. The latter were compiled and summarized to answer the questions addressed on dietary patterns composition. The food group content of dietary patterns reviewed by the DGAC and found to have health benefits formed the basis for answering these questions. WWEIA food group intakes and USDA Food Pattern recommendations were compared with the food group intake data from the healthy dietary patterns as part of the answer for these questions.

The DGAC took the strengths and limitations of data analyses into account in formulating conclusion statements. The grading rubric used for questions answered using NEL systematic reviews do not apply to questions answered using data analyses. Therefore, these conclusions were not graded.

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