USDA Nutrition Evidence Library: methodology used to identify topics and develop systematic review questions for the birth-to-24-mo population.

The USDA's Nutrition Evidence Library (NEL) specializes in conducting food- and nutrition-related systematic reviews that are used to inform federal government decision making. To ensure the utility of NEL systematic reviews, the most relevant topics must be addressed, questions must be clearly focused and appropriate in scope, and review frameworks must reflect the state of the science. Identifying the optimal topics and questions requires input from a variety of stakeholders, including scientists with technical expertise, as well as government policy and program leaders. The objective of this article is to describe the rationale and NEL methodology for identifying topics and developing systematic review questions implemented as part of the "Evaluating the evidence base to support the inclusion of infants and children from birth to 24 months of age in the Dietary Guidelines for Americans--the B-24 Project." This is the first phase of a larger project designed to develop dietary guidance for the birth to 24-mo population in the United States.

Modeling dietary patterns to assess sodium recommendations for nutrient adequacy.

BACKGROUND: The 2010 Dietary Guidelines Advisory Committee report contained dietary patterns developed by using nutrient-dense foods. In most cases, low-sodium forms of foods were incorporated into the patterns. OBJECTIVES: We wanted to determine whether choosing lower-sodium foods could lower the sodium content to 1500 mg without compromising nutrient adequacy. We also explored the effect of choosing typical foods (more calories with higher sodium) and the feasibility of implementing sodium recommendations on a density basis (mg Na/kcal). DESIGN: Food patterns developed during the 2010 Dietary Guidelines development process were used as the base for this analysis. Modeling was then used to analyze the effect of substituting lower-sodium foods on nutrient adequacy. RESULTS: Sodium amounts in the base model varied directly with energy level (1.0 mg Na/kcal) and ranged from 996 to 3176 mg/d. Amounts in the lowest-sodium model also varied with energy level (~0.5 mg/kcal) and ranged from 500 to 1250 mg/d. A comparison of sodium density for the base and the lowest sodium models showed that sodium in the lowest model is ~50% of the base. For typical food choices, sodium amounts were much higher (1.6-2.0 mg/kcal and 1715-5078 mg/d). Comparison of sodium density for the base and the typical food choice models showed that amounts were 1.6-2.0 times greater than the base. CONCLUSIONS: By choosing only low-sodium foods, it was possible to construct nutritionally adequate dietary patterns with 1500 mg Na/d. Sodium density (mg Na/kcal) is a practical approach for expressing sodium recommendations.