Elsevier

Nutrition

Volume 30, Issue 6, June 2014, Pages 613-618
Nutrition

Review
Diet quality concept

https://doi.org/10.1016/j.nut.2013.10.001Get rights and content

Abstract

The term diet quality has recently gained considerable attention in nutritional research. Despite widespread use, it is often poorly defined and remains difficult to measure. Confusion surrounds the term, as there is no consensus on how to define quality of the diet or to pin down a framework for producing a standard indicator. The composite and cut-off selection of most diet quality indices depend on investigator choices in line with research objectives. In addition to the frequently used dietary compliance-based approach, innovative approaches have emerged to construct diet quality indices based on antioxidant and anti-inflammatory profiles of diet. Different viewpoints and overlapping interests may yield different interpretations. Most of the unresolved issues are related directly or indirectly to the multidimensional and open-textured nature of the concept.

This review aims to elucidate several debated key points to understand the reasons behind this confusion and address the complexity of how to define and quantify this concept. A standardized and well-defined framework of diet quality is of great importance for both consumers and scientists from different disciplines.

Introduction

Since early time, humans have attributed to nutrition a functional role in health and well-being [1]. During the past two decades, the term diet quality has emerged in the scientific literature, most often in nutritional epidemiology, to evaluate the population's dietary habits and the efficacy of dietary interventions [2], [3]. Researchers have also envisioned diet quality as a risk assessment tool to predict outcomes such as all-cause mortality, cardiovascular disease, and risk for cancer [4]. Ever since, the understanding of the relationships between food, physiological function, and disease has swiftly progressed.

A plethora of studies have been conducted on methods used to assess overall diet quality with a growing number of scenarios to identify healthy dietary patterns [5]. Numerous dietary indices have been developed, tested and validated to reflect various aspects of diet quality [6]. These vary in composition from simple tools measuring adherence to dietary recommendations, to complex indices requiring substantial analysis of macronutrient and micronutrient intakes. Despite their frequent uses, recent systematic reviews have criticized existing indices as having several drawbacks and most of them are limited in their predictive capacity, thus casting doubts on their relevance and validity [7], [8].

The definition of a concept is the encapsulation of total information about a subject. Although the concept of diet quality became popular in the research arena, capturing all the aspects related to diet quality is challenging. The term remains broadly used, poorly defined, and is often difficult to measure. Confusion still surrounds the term, as there is no consensus on how to define diet quality and to determine a framework for producing a relevant diet quality indicator. Different viewpoints and even vested interests may influence its significance and hence yield different constructions of its composite.

This review aims to elucidate several debated key points to understand the reasons behind the confusion regarding the concept of diet quality and addresses the complexity in how to define and quantify this concept. A standardized and well-defined outline of diet quality is important for both general public and different actors interested in the subject, particularly scientists and practitioners working in the fields of nutrition, public health, toxicology, sociology, and the food industry.

Section snippets

Heterogeneous terminologies

Although the term diet quality has existed for a long time in human history [9], heterogeneous terminologies have been applied in nutritional epidemiology and related disciplines to reflect its significance, such as healthy diet, balanced diet, nutritious food, optimal nutrition, functional foods, overall health-promoting diet, nutrient-rich foods, and so on. Across the literature, diet quality is an umbrella term frequently used to describe how well an individual's diet conforms to dietary

Toward a new global and standard diet quality definition

In light of the points discussed here, it is challenging to outline the diet quality concept and to delimit its application. To date, the nutritional value of diet has almost been extensively measured in a quantitative manner. In order to capture the multidimensional nature of diet quality, the concept should encapsulate, among others, further distinct characteristics, including the following:

  • Sensory organoleptic quality: Assessing the subjective and cognitive perception of consumed foods could

Recommendations for future research

The difficulties inherent in measuring this broadly based, multidimensional concept explain the multiplicity of existing scores and their respective approaches and applications. The following recommendations would be suggested for the future research:

  • 1.

    Diet quality needs to be grasped conceptually and clearly defined, before it can be measured.

  • 2.

    An integrated approach that combines all the different characteristics of diet quality is needed to successfully measure the concept of overall diet

Conclusion

The diet quality concept is currently imprecisely defined, there is a lack of consensus regarding the construct of existing diet quality indicators, and there is uncertainty regarding their relevance as predictors of disease risk. Missing from current indicators is important information surrounding eating patterns, food safety, cultural, and organoleptic properties.

This review presents a simple review of diet quality concept. Careful analysis is needed to determine the best approach to define

Acknowledgments

The author acknowledges Georgina Crichton for her valuable comments on this review. The author has no competing interest.

The present review was supported by a research grant from the National Fund of Research (Fond National de Recherche; project DIQUA-LUX, 5870404).

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