The Nordic Nutrition Recommendations 2022 - principles and methodologies

Abstract

Background: The Nordic Nutrition Recommendations (NNRs) constitute the scientific basis for national dietary reference values (DRVs) and food-based dietary guidelines (FBDGs) in the Nordic and Baltic countries.

Objective: To define principles and methodologies for the sixth edition of NNR to be published in 2022 (NNR2022).

Design: The principles and methodologies of the previous edition of NNR were used as a starting point. Recent nutrition recommendations commissioned by other national food and health authorities or international food and health organizations were examined and dissected. Updated principles and methodologies were agreed by the NNR2022 Committee in a consensus-driven process.

Results: An organizational model with 'checks and balances' was developed to minimize the influence of subjective biases of the committee members and experts. Individual chapters on all included nutrients and food groups will be updated as scoping reviews. Systematic reviews (SRs), which are the main basis for evaluating causal effects of nutrients or food groups on health outcomes, will be embedded in each chapter. A NNR SR Centre will be established for performing de novo SRs on prioritized topics. To avoid duplication and optimize the use of resources, qualified SRs commissioned by other national and international organizations and health authorities will also inform DRVs and FBDGs in NNR2022.

Discussion: The evidence-based methods defined in the NNR2022 project are compatible with most contemporary methods used by leading national food and health authorities. Global harmonization of methodological approaches to nutrition recommendations is strongly encouraged.

Conclusion: Evidence-informed principles and methodologies underpinned by SRs will ensure that DRVs and FBDGs defined in the NNR2022 project are based on the best available evidence and as far as possible free from overt bias.

Keywords: Nordic countries; dietary reference values; evidence-based nutrition; food-based dietary guidelines; national food and health authorities; nutrient recommendations; systematic reviews; the Baltics.

Fig. 1

The NNR2022 project: organization and responsibilities.

Fig. 2

The process for prioritizing and selecting topics for SRs. Abbreviations: SAG, Scientific Advisory Group; qSR, qualified systematic review; ScR, scoping review; NNR SR Centre, NNR Systematic Review Centre; DRVs, dietary reference values; FBDGs, food-based dietary guidelines; PI/ECOTSS, population, intervention/intake/exposure, comparator, outcome, timing, setting, study design.

Fig. 3

Process for defining DRVs and FBDGs: four stages. Abbreviations: SAG; Scientific Advisory Group; qSR, qualified systematic review; ScR, scoping review; NNR SR Centre, NNR Systematic Review Centre; DRVs, dietary reference values; FBDGs, food-based dietary guidelines.

Fig. 4

Principles of Mendelian randomization in nutrition research. (a) Instrumental variable analysis. Figure adapted from (21). (b) Dietary interventions that affect causal disease exposures are clinically important. (c) Instrumental variables can sometimes be used as proxies for dietary intake.

Fig. 5

The theoretical relationship between intake of a nutrient and the effect on the organism.

Fig. 6

Frequency distribution of an individual nutrient requirement. Abbreviations: SD, standard deviation.

Fig. 7

Derivation of Upper Intake Level. Abbreviations: UL, upper intake level; UF, uncertainty factor; NOAEL, no observed adverse effects level; LOAEL, lowest observed adverse effects level.