From tracking energy and sodium intake to shaping dietary indices used worldwide, the “What We Eat in America” program has quietly become one of the most influential data sources in modern nutrition science, fueling research, surveillance, and policy evaluation across the globe.
Study: The Reporting of “What We Eat in America” Nutrient Intake Data in the Scientific Literature: A Scoping Review. Image credit: Hryshchyshen Serhii/Shutterstock.com
A recent study in the Journal of Nutrition examined the extent to which The What We Eat in America (WWEIA) nutrient data have been reported in the peer-reviewed scientific literature.
The What We Eat in America (WWEIA), a component of the US national dietary surveillance program called National Health and Nutrition Examination Survey (NHANES), plays a crucial role in informing and evaluating healthcare and public health policies, nutritional guidelines, and food programs.
Importance of national dietary surveillance
Assessing the nutrient content of foods through national dietary surveillance is essential. The U.S. Department of Agriculture (USDA) plays a key role in characterizing foods based on their nutrient profiles. For over two decades, the NHANES has been conducted continuously in the United States, serving as the federal government’s premier program for evaluating the health and nutritional status of the population.
WWEIA serves as the dietary intake component of the U.S. NHANES, a principal national surveillance program managed jointly by the USDA and the U.S. Department of Health and Human Services (HHS). WWEIA collects two 24-hour dietary recalls from a representative sample of non-institutionalized Americans using the Automated Multiple-Pass Method (AMPM). The resulting data are used to support public health policy, develop nutrition guidelines, and evaluate food programs.
The Food and Nutrient Database for Dietary Studies (FNDDS), developed and maintained by the USDA, forms the foundation for determining nutrient values. Specifically designed to analyze dietary intake data from the WWEIA, NHANES, FNDDS, and the AMPM, these functions serve as interconnected tools within national dietary surveillance. The food and beverage items listed in FNDDS are based on AMPM questions and response options. Beyond nutrient and food component values for foods and beverages consumed in the United States, FNDDS also includes comprehensive reference data for all nutrient values.
Examining a decade of nutrition studies
The current review included all nutrient components, referred to as nutrients, estimated in FNDDS, except for added vitamin E and vitamin B12. This scoping review included publications that analyzed the U.S. population or its subgroups using WWEIA or NHANES dietary intake data. All research contexts and applications of nutrient analyses were considered, except studies focused solely on dietary supplement intakes.
Eligible studies were English-language publications from January 2013 to October 2023 that reported at least one nutrient using WWEIA, NHANES data from any cycle of continuous NHANES (1999–2020). All relevant studies were obtained from multiple databases, including Ovid MEDLINE.
Global reliance on U.S. diet data
A total of 12,589 studies appeared in the initial search. After removing duplicates, 2,203 studies met the inclusion criteria and were included in the scoping review. The number of studies increased nearly fourfold, from 106 in 2013 to 414 in 2022. Between January 1 and October 18, 2023, 375 studies had been published, reflecting the partial year covered by the review.
Of the 2,203 publications reviewed, energy was cited in 78 % of research. Nutrients commonly reported in at least a quarter of the publications included total saturated fatty acids (SFAs), sodium, protein, polyunsaturated fatty acids (PUFAs), dietary fiber, monounsaturated fatty acids (MUFAs), total fat, and carbohydrates.
Of the 63 nutrients examined, 42 appeared in over 100 studies, 26 in more than 300, and 11 in over 500. The least frequently reported nutrients were individual SFAs and MUFAs, as well as theobromine, each of which was reported in about 2 % of studies. At least one mineral, mostly sodium, was reported in 57 % of studies. At least one vitamin was featured in approximately 35 % of articles, with vitamin C being the most reported (22 %).
Researchers from 60 countries across six continents contributed to these studies. Approximately 18 % of the publications had authors from multiple countries. Most studies included authors from North America (64 %), followed by Asia (37 %), Europe (9 %), South America (3 %), Oceania (2 %), and Africa (1 %).
Thirty-one percent of the publications used one of 38 dietary indices, a more than threefold increase over ten years. The USDA’s Healthy Eating Index (HEI) and the Dietary Inflammatory Index were the most frequently used, while other indices each appeared in 5 % or fewer of these studies. Fourteen percent of studies focused only on children (≤19 years), 51 % on adults (≥20 years), and 33 % included both age groups. About 9 % of the studies used WWEIA and NHANES data linked to mortality outcomes.
WWEIA reporting trends highlight lasting research and policy value
This is the first study to systematically review how often national dietary surveillance data are reported in scientific literature. The number of studies grew fourfold over 10 years, with contributions from researchers worldwide. Typically, nutrients with established roles in chronic disease risk and public health guidelines, such as energy, protein, sodium, and total SFAs and PUFAs, appear most frequently in the literature. The diverse and widespread use of these continuously collected, nationally representative data highlights their ongoing importance in nutrition research.
Advances in dietary assessment methods and analytics, as well as integration with new data sources, will further enhance the value of WWEIA, NHANES data. Continued improvements in data accessibility, accuracy, and granularity will enable more targeted research on population subgroups and dietary trends. As nutrition science evolves, these robust datasets will remain essential for informing policy, guiding dietary recommendations, and meeting future public health challenges.
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