Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2017 Jan;105(1):249S-285S.
doi: 10.3945/ajcn.116.139097. Epub 2016 Dec 7.

Options for basing Dietary Reference Intakes (DRIs) on chronic disease endpoints: report from a joint US-/Canadian-sponsored working group

Elizabeth A Yetley  1 , Amanda J MacFarlane  2 , Linda S Greene-Finestone  3 , Cutberto Garza  4   5   6 , Jamy D Ard  7 , Stephanie A Atkinson  8 , Dennis M Bier  9 , Alicia L Carriquiry  10 , William R Harlan  11 , Dale Hattis  12 , Janet C King  13   14   15 , Daniel Krewski  16 , Deborah L O'Connor  17   18 , Ross L Prentice  19   20 , Joseph V Rodricks  21 , George A Wells  22
Affiliations
Review

Options for basing Dietary Reference Intakes (DRIs) on chronic disease endpoints: report from a joint US-/Canadian-sponsored working group

Elizabeth A Yetley et al. Am J Clin Nutr. 2017 Jan.

Abstract

Dietary Reference Intakes (DRIs) are used in Canada and the United States in planning and assessing diets of apparently healthy individuals and population groups. The approaches used to establish DRIs on the basis of classical nutrient deficiencies and/or toxicities have worked well. However, it has proved to be more challenging to base DRI values on chronic disease endpoints; deviations from the traditional framework were often required, and in some cases, DRI values were not established for intakes that affected chronic disease outcomes despite evidence that supported a relation. The increasing proportions of elderly citizens, the growing prevalence of chronic diseases, and the persistently high prevalence of overweight and obesity, which predispose to chronic disease, highlight the importance of understanding the impact of nutrition on chronic disease prevention and control. A multidisciplinary working group sponsored by the Canadian and US government DRI steering committees met from November 2014 to April 2016 to identify options for addressing key scientific challenges encountered in the use of chronic disease endpoints to establish reference values. The working group focused on 3 key questions: 1) What are the important evidentiary challenges for selecting and using chronic disease endpoints in future DRI reviews, 2) what intake-response models can future DRI committees consider when using chronic disease endpoints, and 3) what are the arguments for and against continuing to include chronic disease endpoints in future DRI reviews? This report outlines the range of options identified by the working group for answering these key questions, as well as the strengths and weaknesses of each option.

Keywords: Dietary Reference Intakes; chronic disease; evidence assessments; evidentiary challenges; intake response.

PubMed Disclaimer

Figures

FIGURE 1
FIGURE 1
Hierarchy of evidence pyramid. The pyramidal shape qualitatively integrates the amount of evidence generally available from each type of study design and the strength of evidence expected from indicated designs. In each ascending level, the amount of available evidence generally declines. Study designs in ascending levels of the pyramid generally exhibit increased quality of evidence and reduced risk of bias. Confidence in causal relations increases at the upper levels. *Meta-analyses and systematic reviews of observational studies and mechanistic studies are also possible. RCT, randomized controlled trial.
FIGURE 2
FIGURE 2
Conceptual framework for assessing causality on the basis of level of confidence that the intake–chronic disease relation is causal. Panel A: Direct assessment involving the measurement of both intake and chronic disease outcome (event or incidence); highest confidence that relation is causal. Panel B: Indirect assessment involving the measurement of a qualified surrogate disease marker as a substitute for a direct measurement of the chronic disease per se; provides a reasonable basis, but not absolute certainty, that the relation between the intake and the chronic disease is causal. Panel C: Indirect assessment involving the measurement of a nonqualified disease marker as a substitute for a direct measurement of the chronic disease; because this type of outcome measure lacks sufficient evidence to qualify as a substitute for the chronic disease of interest, there is considerable uncertainty as to whether the relation between the intake and the chronic disease is causal. Shaded boxes indicate variables and outcomes that are measured directly. Nonshaded boxes indicate variables or outcomes that are not measured but whose presence on the causal pathway is inferred. Arrows indicate a unidirectional, causal relation. This type of relation can be directly assessed by randomized controlled trials. If observational studies (e.g., prospective cohort studies) are being assessed, the observed relations are associations, not causal links. Solid bold arrows indicate a relation with high confidence. Dashed arrows indicate relations with some uncertainty. Lighter arrows indicate less certainty than bolder arrows. If any part of the causal pathway between intake and chronic disease outcome has uncertainty, then the entire causal pathway has uncertainty. “Qualified” biomarkers of outcome require strong evidence that their use as substitutes for unmeasured outcomes can accurately and reliably predict the outcome of interest. “Qualification” has a contextual basis in that the evidence about its use as a substitute for an unmeasured outcome needs to be relevant to the proposed use of the biomarker (e.g., relation between food-substance intake and a chronic disease). Intakes can be assessed directly or by measurement of qualified biomarkers of intake.
FIGURE 3
FIGURE 3
Framework for evidence integration. Adapted from reference with permission.
FIGURE 4
FIGURE 4
Relations of intakes and adverse effects of substances that are nutritionally necessary. EAR, Estimated Average Requirement; RDA, Recommended Dietary Allowance; UL, Tolerable Upper Intake Level. Reproduced from reference with permission.
FIGURE 5
FIGURE 5
Intake-response relations between the intake of a food substance and chronic disease risks can vary. The intake of a food substance could decrease (A) or increase (B) chronic disease risk. The intake of a food substance could be independently related to multiple chronic diseases that show different and overlapping dose-response relations (C). The relation or relations between the intake of the food substance and chronic disease or diseases might not be monotonic. The background risk of a given chronic disease is not zero. “Substances” could be individual food substances or groups of interacting substances. UL, Tolerable Upper Intake Level.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes: the essential guide to nutrient requirements. Washington (DC): National Academies Press; 2006. [cited 2016 May 4]. Available from: https://fnic.nal.usda.gov/sites/fnic.nal.usda.gov/files/uploads/DRIEssen....
    1. Taylor CL. Framework for DRI development components “known” and components “to be explored” background paper. Food and Nutrition Board, Institute of Medicine; 2008 [cited 2016 May 4]. Available from: https://fnic.nal.usda.gov/sites/fnic.nal.usda.gov/files/uploads/Framewor....
    1. Murphy SP, Yates AA, Atkinson SA, Barr SI, Dwyer J. History of nutrition: the long road leading to the Dietary Reference Intakes for the United States and Canada. Adv Nutr 2016;7:157–68. - PMC - PubMed
    1. Goodman RA, Posner SF, Huang ES, Parekh AK, Koh HK. Defining and measuring chronic conditions: imperatives for research, policy, program, and practice. Prev Chronic Dis 2013;10:E66. - PMC - PubMed
    1. WHO. Noncommunicable diseases. Media centre fact sheet. 2015 [cited 2016 Nov 1]. Available from: http://www.who.int/mediacentre/factsheets/fs355/en/.

Publication types