Part D. Chapter 1: Food and Nutrient Intakes, and Health: Current Status and Trends - Continued
Needs for Future Research
- Expand WWEIA participation to include more respondents from race/ethnic minorities and non-U.S. born residents.
Rationale: Very little is known about the dietary habits of many of the cultural subgroups in the United States. This knowledge is essential to moving forward any nutrition programs for first and second generation immigrants. More data on the impact of acculturation also are needed on food and health behaviors. The number of participants in WWEIA using the derived acculturation variable was too small for any analysis. Finally, “Hispanic” is a very broad term and a better understanding is needed of the nutritional profiles (including shortfalls and excesses) across various Spanish-speaking people in the United States, who come from different cultural backgrounds with distinct eating patterns.
- Include higher proportion of older Americans as respondents in WWEIA.
Rationale: More data are needed on dietary intake of older adults; the sample sizes in WWEIA were too small for any meaningful analyses for those older than the age of 71 years. In addition to nutrient intake, additional information is needed on whether older adults are able to shop and cook, whether polypharmacy plays a role in nutritional adequacy, and whether co-morbidities, such as poor dentition, musculo-skeletal difficulties, arthralgias and other age-related symptoms, affect their ability to establish and maintain proper nutritional status.
- Increase the number of pregnant women as respondents in WWEIA.
Rationale: The number of pregnant women in WWEIA is currently too small to properly evaluate the status and trends in food and nutrient intake in pregnant women. Since good nutrition in pregnancy is critical to proper growth development of the infant it is critical to properly evaluate food and nutrient intake, which will inform recommendations and public policies for pregnant women.
- Conduct research on nutrition transitions from childhood to shed light on how and why dietary intake changes so rapidly from early childhood through pre-adolescence and adolescence, and to identify the driving forces behind dietary intake change in these age groups and what programs are most effective at maintaining positive nutrition habits established in very young children.
Rationale: Young children have better dietary intake than older children and adolescents. It is important to maintain the positive gains made in early childhood and identify factors responsible for the declines in intakes of fruit, dairy, and other food groups and increases in added sugars and refined grains as children enter the elementary school age years, as poor eating patterns in elementary school seem to persist into adolescence and beyond.
- Evaluate the effects of common variations in dietary patterns in small children on nutrient intakes.
Rationale: Children from 2 to 4 years of age have a highly variable diet and often do not fit readily into the USDA Food Pattern food groups diet pattern analyses. Further information is needed to understand the broad range of diets and supplement use in small children and how this relates to nutrient intake and growth. Research is needed to better characterize their diets so that appropriate guidance can be offered.
- Increase the quantity and quality of food composition databases available for research.
Rationale: Accurate assessment of nutrient intake and trends over time in the U.S. population is dependent upon the quality of food composition data. Tens of thousands of foods are available for purchase and consumption in the United States, but accurate nutrient content data are available only for less than 10,000 foods and are almost non-existent for many ready-to-eat and restaurant-type foods. Analytic values from foods are needed on specific nutrients and components, such as vitamin D, fiber, added sugars, and sodium. Improved food composition data also is critical for needed research to better define, identify, and quantify total grain, whole grain consumption, and refined grain consumption in dietary studies.
- Investigate the validity, reliability, and reproducibility of new biomarkers of nutrient intake and biomarkers of nutritional status.
Rationale: Limited biomarkers are available and some that are available are difficult to interpret due to other contributing factors to the biomarker measure (e.g., vitamin D is obtained in the diet and is also endogenously synthesized).
- Evaluate effects of fortification strategies and supplement use on consumer behavior related to the intake of foods and supplements containing key nutrients, including calcium, vitamin D, potassium, iron, and fiber.
Rationale: The intake of key nutrients of concern is considerably affected by the rapidly evolving marketplace of food fortification and supplementation. Understanding consumer behavior related to fortification and supplementation would be important in predicting the effects of interventions and marketplace changes in content of these nutrients. Special interest exists regarding fortification strategies of foods, including whole grains and yogurts, in allowing individuals to reach the RDA for vitamin D without using supplements. Data are needed on how supplements may help meet nutrient shortfalls and/or how use of supplements may place individuals at risk of overconsumption. Research on effective consumer guidance is needed.
- Understand the rationale for and consequences of the use of supplements above the UL for vitamins and minerals. Identify biochemical markers that would indicate the effects of high-dose supplement use.
Rationale: Consumer use of high-dose supplements has increased. Understanding the influences guiding this use would be helpful in considering how to educate consumers about safe upper intake limits.
- Develop a standardized research definition for meals and snacks.
Rationale: Multiple different criteria are used in studies to define a snack or meal occasion, such as time of day, the types or amounts of food consumed, or subjective assessment by the study respondent. Researchers should work toward a consensus on the use of standard definitions.
- Understand better the concept of dietary patterns and design approaches to quantify the diet in large population-based studies.
Rationale: More methodological work on dietary patterns is needed. For example, food frequency questionnaires, which are used in most diet assessment studies, do not capture data on meal timing, meal frequency, or the types of foods consumed together. Studies using diet recalls and records are better at capturing specific foods and their quantities consumed (portion sizes) and the types of foods eaten together, but often these detailed assessment methods are not feasible for large population-based studies. Quantification of food group intake is needed. In addition, dietary patterns research encompasses a broader scope of issues than can be addressed by diet scores and data drive approaches.
- Consistently report the nutrients, foods, and food groups that are used to evaluate dietary patterns in published studies.
Rationale: The current scientific literature evaluating dietary patterns and health is inconsistent in its provision of dietary patterns composition information. This makes it difficult to compare, across studies, the components of healthful patterns that are associated with health benefits.
- Conduct population surveillance on the prevalence and trends of nutrition-related chronic diseases including type 2 diabetes, cardiovascular disease, some cancers, osteoporosis and neurocognitive disorders.
Rationale: Current data on diabetes in adults cannot be stratified by disease type (type I or type II), making it very difficult to monitor incidence and prevalence of type 2 diabetes. Continued population surveillance is needed to effectively link nutritional factors with risk of these diseases.