The contribution of mixed dishes to vegetable intake among US children and adolescents

The 2010 Dietary Guidelines for Americans call for an increase in consumption of vegetables due to their high nutrient profile, protective association with certain chronic diseases and relatively low energy content(1). Although they do not advocate for one specific eating pattern, these dietary guidelines do emphasize the importance of nutrient-dense foods in the diet and recommend increased intake of nutrient-dense foods, particularly vegetables, with little added solid fats or sugars(1). In addition, the guidelines continue to recognize that some forms of vegetables are more healthful than others, such as dark-green or orange vegetables, and give specific recommendations for intake(1); however, the guidelines do not give specific recommendations for how much vegetable consumption should be in whole forms, or forms where a vegetable is eaten primarily by itself, whether raw or cooked, without other added ingredients or foods, or as part of other dishes where vegetables may not be the main ingredient. In dietary research, vegetables are often treated as a broad classification that may or may not include vegetables from mixed dishes, such as pizza, or those that include a relatively high proportion of white or fried potatoes that US children and adolescents are known to consume but generally are of lower nutritional value(1). Distinguishing between vegetables eaten in their whole forms and those contained within mixed dishes is important due to the potential differences in added fats and sugars, as well as nutrient profile, associated with these categorizations. These distinctions remain under-explored in the literature, particularly among children. Vegetables may often be eaten as part of mixed food dishes (e.g. tomato sauce on pizza), particularly by children who may resist eating vegetables in their whole forms due to issues regarding preference and undeveloped taste(2). Although mixed dishes may be a way to incorporate more vegetables into children’s diets, they also may provide more unfavourable aspects of dietary intake, such as greater intake of energy, fat or added sugar, especially when compared with vegetables in their whole forms. Some national nutritional data sets and databases in the USA commonly used to estimate food intake, such as the US Department of Agriculture’s (USDA) My Pyramid Equivalent Database (MPED), capture servings of vegetables eaten as part of mixed dishes; while others, such as the National Health and Nutrition Examination Survey (NHANES) individual food files, do not. Therefore, measurement and quantification of overall vegetable intake may differ according to the database used. This could lead to variable estimates of population vegetable intake depending on the amount vegetables eaten as part of mixed dishes contribute to overall vegetable intake. However, there has been little recent description of vegetables eaten as mixed dishes υ. whole forms in the diets of children and adolescents and how this may impact overall intake, an issue recently highlighted in a review by Roark and Niederhauser(3). The objectives of the present analysis are twofold. First, we aim to describe vegetable intake among children and adolescents in more specific detail according to type of vegetable and source of vegetable (i.e. whole form or mixed dish) and second to examine how the use of different dietary databases and coding schemes affects population estimates of vegetable intake among children and adolescents. We also examine potential differences in forms of vegetable consumption by demographic characteristics.