Keywords

FormalPara Key Points

  • Diet quality scores are related to health outcomes. Thus, diet quality is as important as quantity, a fact which is overlooked when food security is measured.

  • However, an evidence-based approach to the assessment, measurement and application of diet quality is required to improve morbidity and mortality due.

  • This chapter lists the most up-to-date resources on the regulatory bodies, journals, books, professional bodies and websites that are relevant to an evidence-based approach to diet quality.

Introduction

The availability of or access to sufficient calories (i.e. “food security”) is increasing worldwide [1]. However, food-secure individuals and populations with access to sufficient calories (i.e. adequate quantities of food) may still lack essential nutrients or those dietary components that are yet unmasked as being important for human health. These components are encompassed within the concept of “diet quality”. Diet quality scores are related to health outcomes. So despite “food security” nutritional inadequacies in poor-quality diets (“hidden hunger”) increase the risk of both short- and long-term morbidity and mortality. Thus, diet quality is as important as quantity, a fact which is overlooked when food security is measured. However, the term “diet quality” itself is subjected to a variety of interpretations, definitions and usage.

Methods of measuring diet quality have recently been developed and several scoring systems have been derived. Diet quality can be measured by scoring food patterns relative to national dietary guidelines and the diversity of healthy choices within core food groups. On the other hand, some have interpreted diet quality in terms of micro- or macronutrient profiles of single food items. In our view, both are valid especially when considered with the wider context of food and nutrition. Nevertheless, assessment of the quality and variety of the whole diet allows analysis of associations between foods and health status to be undertaken in order to determine risk factors. Refinement of diet quality scoring systems has facilitated identification of both protective and harmful diets. They also potentially unmask dietary components that are not essential for life per se but have been shown to significantly improve health-related outcomes. These include, for example, polyphenols in wine (when consumed moderately).

Diet quality scores are inversely related to health outcomes. So despite ‘food security’ nutritional deficiencies in poor-quality diets (‘hidden hunger’) increase the risk of both short- and long-term morbidity and mortality. One review reported that improved diet quality reduced all-cause mortality up to 42 %, cardiovascular disease (CVD) mortality by up to 53 %, CVD risk by up to 28 %, cancer mortality by up to 30 % and all-cancer risk by up to 35 % [2]. This does not mean to say that diet quality is related to just the physical manifestations of disease. For example, a better diet quality has been shown to be related to a reduced cognitive decline in the elderly over an 11-year period [3].

Thus, diet quality is as important as quantity, a fact which is overlooked when food security is measured. Targeted nutritional interventions may improve the most critical aspects of an individual’s or population’s specific deficiencies [1]. However, an evidence-based approach to the assessment, diagnosis and treatment of nutritional deficiencies is required to prevent morbidity and mortality from either inadequate or excessive micronutrient supplementation. This does not mean that all diseases are related to diet quality. For example, one recent study on ovarian cancer specifically showed no relationship with diet quality assessed with the Health Eating Index [4]. Studies like the aforementioned, albeit negative, allow health professionals to redirect their investigations to other causative mechanisms (e.g. epigenetics or environmental risk factors) and reaffirm the need for an evidence-based approach. Other examples of the definitions, measurement and applications of diet quality can be found in this book and also via the recommended resources in the tables below.

Tables 28.1, 28.2, 28.3, 28.4, and 28.5 list the most up-to-date information on the regulatory bodies (Table 28.1), journals (Table 28.2), books (Table 28.3), professional bodies (Table 28.4) and websites (Table 28.5) that are relevant to an evidence-based approach to diet quality.

Table 28.1 Regulatory bodies
Full size table
Table 28.2 Journals
Full size table
Table 28.3 Books
Full size table
Table 28.4 Professional societies
Full size table
Table 28.5 Relevant internet resources (i.e. those devoted to micronutrient deficiency)
Full size table