Indicators for the evaluation of diet quality.

The role of diet quality and physical activity in reducing the progression of chronic disease is becoming increasingly important. Dietary Quality Indices or Indicators (DQIs) are algorithms aiming to evaluate the overall diet and categorize individuals according to the extent to which their eating behaviour is "healthy". Predefined indexes assess dietary patterns based on current nutrition knowledge and they have been developed primarily for nutritional epidemiology to assess dietary risk factors for non-communicable diseases. There are many different types of DQIs. There are three major categories of DQIs: a) nutrient-based indicators; b) food/food group based indicators; and c) combination indexes, the vast majority of DQIs, which often include a measure of diet variety within and across food groups, a measure of adequacy i.e. nutrients (compared to requirements) or food groups (quantities or servings), a measure of nutrients/foods to consume in moderation, and an overall balance of macronutrients. The Healthy Eating Index (HEI), the Diet Quality Index (DQI), the Healthy Diet Indicator (HDI) and the Mediterranean Diet Score (MDS) are the four 'original' diet quality scores that have been referred to and validated most extensively. Several indexes have been adapted and modified from those originals. In particular, many variations on the MDS have been proposed, included different alternate MDS and Mediterranean Diet Adherence Screener (MEDAS). Primary data source of DQI's are individual dietary data collection tools, namely 24 h quantitative intake recalls, dietary records and food frequency questionnaires. Nutrients found in many scores are total fat, saturated fatty acids or the ratio of monounsaturated fatty acids to saturated fatty acids or the latter SFA to polyunsaturated fatty acids. Cholesterol, protein content and quality, complex carbohydrates, mono- and disaccharides, dietary fibre and sodium are also found in various scores. All DQIs, except those that only contain nutrients, include the components fruits and vegetables; additional attributes are legumes or pulses, nuts and seeds. Meat and meat products, namely red and processed meat, poultry, and milk and dairy products are also included in many scores. Other foods contained in some DQIs e.g. MDS are olive oil and fish. Nowadays, there is interest in defining more than DQIs, healthy life indices (HLIs), which give information on behaviours associated with specific patterns and beyond dietary habits they include physical activity, rest and selected socio-cultural habits. The Mediterranean Lifestyle (MEDLIFE) index has been recently created based on the current Spanish Mediterranean food guide pyramid and it includes both the assessment of food consumption directly related to the Mediterranean diet, physical activity and rest and other relevant cultural information. However, a global HLI should consider, based on the Iberoamerican Nutrition Foundation (FINUT) Pyramid of Healthy Lifestyles, in addition to food groups and nutrients, selected items on food safety e.g. consumption rate of proceed foods, food handling, preparation and storage and access to drinking water, selected food habits, including alcoholic beverage and salt consumption patterns, purchase of seasonal and local foods, home cooking and conviviality, as well as patterns of physical activity, sedentary and rest habits and some selected sociocultural habits, particularly those related to food selection, religious beliefs and socializing with friends.

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