Increase Font Size Decrease Font Size View as PDF Print

2015 DGAC Nutrition Evidence Library Methodology


Nutrition Evidence Library (NEL) systematic reviews (SRs) are designed to address food and nutrition-related topics that are important to Federal government policy and program decision-making. The methodology used by NEL to conduct SRs is designed to be transparent and reproducible, and to minimize bias. The following represent overarching principles for the NEL process:
  • The Dietary Guidelines Advisory Committee (DGAC) makes all substantive decisions required during the process.
  • NEL staff provides facilitation and support to ensure that the process is consistently implemented in accordance with NEL methodology.
  • NEL uses document templates, which serve as a starting point and are tailored to the specific review.
  • When working with a DGAC, the Science Review Subcommittee provides oversight to the DGAC’s work throughout their deliberative process, ensuring that the Subcommittees use consistent and transparent approaches when reviewing the evidence using NEL SRs.
The roles and responsibilities of those individuals involved in NEL SR projects are described below.
Systematic Review Management Team
Each NEL SR project is planned, organized, and guided by a Systematic Review Management Team composed of Federal nutritionists and two librarians who have been trained in systematic review methodology.
  • NEL Lead: Responsible for all aspects of planning, facilitating, and conducting the work necessary for timely execution of SRs.
  • NEL Secondary Lead: Provides support to the NEL Lead as needed. May play the lead role in planning, facilitating, and conducting some SRs.
  • NEL Librarian: Works with the NEL Lead and Secondary Lead to develop implement, refine and document the literature search strategies.
  • Technical Advisor: NEL staff member with recognized subject matter expertise in an area who may be appointed to assist the NEL Lead in the SR development process and technical execution.
Dietary Guidelines Advisory Committee
The Dietary Guidelines Advisory Committee (DGAC) is one specific expert group that the NEL works with. The DGAC is chartered following Federal Advisory Committee Act (FACA) guidelines, and is composed of nationally recognized experts in the field of human nutrition and chronic disease prevention. The DGAC examines the state of current scientific evidence using SRs, data analyses, and/or food pattern modeling analyses, as well as scientific evidence-based reports, input from expert guest speakers, and oral and written comments from the public. The DGAC then submits an Advisory Report of its recommendations with rationales to the Secretaries of Health and Human Services and U.S. Department of Agriculture for consideration in developing the Dietary Guidelines for Americans policy document.
NEL Fellows and Abstractors
NEL Fellows and Abstractors are National Service Volunteers from across the United States with advanced degrees in nutrition or a related field. They are trained to review individual research articles included in NEL SRs. They extract data from the research articles and post this information to data fields in evidence worksheet templates in the NEL online portal, and assess the risk of bias of each individual study using the NEL Bias Assessment Tool. NEL Fellows, who contribute a higher level of commitment to the NEL, may also provide support to the NEL by screening literature and assisting in preparation and/or review of other components of a NEL SR.

More information on the 2015 DGAC Nutrition Evidence Library Methodology

Last Updated: 01/22/2014