Applying Retrospective Harmonization to the Field of Nutrition and Cognitive Health


The 2020 Dietary Guidelines Advisory Committee (DGAC) explored neurocognitive health through several systematic reviews and was faced with a literature having “considerable variation in testing methods, inconsistent validity and reliability of cognitive testing methods, and differences between dietary patterns and cognitive outcomes examined,” reducing the ability to draw conclusions (USDA/HHS 2020). The lack of harmonization is a long-standing challenge in the field of nutrition and cognition, recognized over many decades. As the challenge faced by the 2020 DGAC is likely to still be in place for the 2025 DGAC’s review, one potential solution is to develop an approach to this literature.

Retrospective harmonization approaches may be one way to enable better use of more of the prior research to inform current dietary guidance. These approaches involve placing disparate measures on a common scale. In this way, the value of individual studies using these two different measures can be magnified to better inform clinical practice. A similar approach could be taken for measures commonly used in the nutrition and cognition field. This project involves formation of an Expert Group to develop guiding principles for retrospective harmonization in the field of nutrition and cognition, as well as exploration of a pilot exercise using data from large-scale observational studies and focusing on a specific cognitive outcome.

Expert Group:

Lyn Steffen, PhD, MPH, University of Minnesota – Co-Chair

Rafael de la Torre Fornell, PharmD, IMIM-Hospital del Mar Medical Research Institute – Co-Chair

Amaia Ayala-García, PhD, MPH, Hospital del Mar Research Institute, Barcelona, Spain

Courtney K Blackwell, PhD, Northwestern University

Christina Khoo, PhD, Ocean Spray Cranberries

Maxwell Armand Mansolf, PhD, Northwestern University

Emilio Ros, MD, PhD, IDIBAPS, Barcelona, Spain

Natalia Soldevila-Domenech, PhD, MPH, Hospital del Mar Research Institute, Barcelona, Spain

Linda Snetselaar, PhD, RD, University of Iowa

Tina Wey, PhD, Maelstrom Research, McGill University Health Centre

So Yun Yi, MPH, University of Minnesota

Year: 2023

Read more: Diet Patterns Associated with Cognitive Decline: Methods to Harmonize Data from European and US Cohort Studies

View this project on the Center for Open Science's Open Science Framework.

This work was supported by the IAFNS Cognitive Health Committee.