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Practice Applications USDA Center for Nutrition Policy and Promotion Corner| Volume 117, ISSUE 4, P519-521, April 2017

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Healthy Eating Index—Beyond the Score

Published:March 23, 2017DOI:https://doi.org/10.1016/j.jand.2017.02.002
      The Healthy Eating Index (HEI) is a measure of diet quality that is based on key recommendations of the Dietary Guidelines for Americans (DGA). The DGA as well as the HEI are a result of collaborations between nutritionists at the US Department of Health and Human Services and the US Department of Agriculture (USDA). The current version is HEI-2010, which reflects the 2010 DGA and includes component scores for total fruit, whole fruit, total vegetables, greens and beans, whole and refined grains, total protein foods, seafood and plant-based protein foods, sodium, and calories from solid fats, added sugar, and alcohol beyond a moderate level. The updated HEI-2015, to be released later this year, will reflect the 2015-2020 DGA. Starting with the 2005 version, the HEI has used a universal set of scoring standards. One feature of the universal scoring metric is the density approach used to calculate amounts per 1,000 kcal. This approach allows researchers to assess the quality of a mix of foods independent of food quantity. In addition, no single food is required for an optimal score and the HEI components reflect the USDA Food Patterns. The basic food groups are considered culturally neutral, which accounts for individual preferences within food groups. These features contribute to the breadth of applications in a variety of research settings.
      Nutritionists at the Center for Nutrition Policy and Promotion (CNPP) explored the literature to assess the various research applications of the HEI-2005 and HEI-2010 from 2008 to 2016. The purpose of this article is to share various HEI applications that have been published and to spur thought on additional ways that the HEI could be used for measuring diet quality as defined by the DGA.

      Selected Applications of HEI-2005 and HEI-2010 in the Literature

      There have been over 185 scientific publications describing studies that use the HEI-2005 since its release in 2008. Over 100 papers have been published that used HEI-2010, which was released in 2013. The number and scope of publications continued to grow each year; over 50 papers were published in 2016 alone. The Figure illustrates the increasing number of publications using HEI-2005 and 2010 between 2008 and 2016. By 2016, nearly all publications were using the HEI-2010. Many of these publications, including the descriptions of the HEI-2005 and the HEI-2010, are published in the Journal of the Academy of Nutrition and Dietetics as well as many other journals and federal publications.
      Figure thumbnail gr1
      FigureNumber of publications using the Healthy Eating Index-2005 (HEI-2005) and HEI-2010 between 2008 and 2016.
      The range of applications spans studies in the areas of epidemiology, population monitoring, and nutrition interventions. A few studies investigate the association between diet quality and biomarkers, both markers of dietary intakes as well as those associated with disease outcomes. A smaller number of studies examine the diet quality of a particular set of foods in the food environment. Here we highlight the breadth of applications of the HEI-2005 and HEI-2010 in the literature.

      Diet and Chronic Disease

      Nearly 70 studies examined either the prospective or cross-sectional associations between overall diet quality and health outcomes. Many of these studies describe how diets that align with the DGA relate to diet-related chronic disease including cancer, cardiovascular disease, and type 2 diabetes. The DGA provide guidance for a healthy diet that focuses on preventing diet-related chronic disease; however, the HEI can be used to assess diet quality and health outcomes in populations with existing chronic disease diagnoses. Examples include associations between diet quality and risk for cardiovascular disease related deaths and diet quality among cancer survivors. Intervention studies that relate to chronic disease outcomes also exist. For example, the impact of dietary interventions on diet quality and improvements in glycemic control for those with type 2 diabetes.

      Population Estimates of Diet Quality

      The HEI is appropriate for examining diet quality of the US population as well as specific subgroups of the population such as children and adolescents, older adults, and specific race-ethnic populations.
      The What We Eat in America portion of the National Health and Nutrition Examination Survey (NHANES) is a commonly used dataset for assessing diet quality in the US population. About 90 publications used NHANES data to answer research questions related to diet quality, including associations between diet quality and health outcomes, biomarkers of disease risk, and associations between health behaviors and diet quality.

      Children

      Nearly 70 publications describe studies that use the HEI to assess diet quality of children and adolescents. Examples of research topics include associations between television viewing time and diet quality, diet quality as a predictor of dental caries, and the effect of food away from home on diet quality. Several studies assess diet quality of children participating in federal nutrition programs.

      Federal Nutrition Programs

      The DGA are the foundation for all federal nutrition programs, and the HEI provides a way to measure the diet quality of the foods those programs make available as well as the diet quality of the groups the programs serve. Peer-review publications as well as federal reports were identified that either assess diet quality of foods made available through federal nutrition programs or assess diet quality of participants in federal nutrition programs such as the Supplemental Nutrition Assistance Program, the National School Lunch Program, and the Supplemental Nutrition Program for Women, Infants, and Children. These federal food-assistance programs aim to improve food security and improve nutrition in vulnerable populations, and many of the related studies highlight disparities in diet quality across income groups, education levels, and other socio-demographic indicators.

      Food Environment

      The HEI can also be used to assess diet quality of different levels of the food environment and food availability. Over 20 studies were identified in which the HEI was used for this purpose. Studies have calculated the HEI scores of restaurant menus, grocery store circulars, as well as the entire US food supply to assess how well the mix of foods available to consumers aligns with the DGA. Assessing the US Food Availability Data lets us know whether the food supply supports population level consumption of foods that align with the DGA. Evaluations of the food supply often reveal areas in which food availability could improve. For example, the food package offered through the USDA Food Distribution Program on Indian Reservations (FDPIR) has been assessed, and the HEI score highlighted a food availability HEI score that is higher than population intakes as well as opportunities for FDPIR to improve its offerings.

      Global Applications

      The HEI has been used to assess diet quality in many countries other than the United States. For some countries, the HEI serves as the template for a diet quality index adapted to the country specific guidance. For example, researchers in Brazil adapted an early version of the HEI for use with the Brazilian population. The HEI-2005 and 2010 have been used in countries other than the United States without adaptation to the scoring algorithm. These countries include Iran, China, Greece, Italy, Puerto Rico, Spain, Belgium, Sweden, France, and Malaysia. As mentioned previously, the 12 components in the HEI reflect basic food groups that are culturally neutral. Though intended to reflect dietary guidance in the United States, the HEI can be a useful tool for assessing diet quality in countries that may not have their own index or in instances where there is a desire to compare associations between an established definition of diet quality and health outcomes.

      Implications

      The breadth of research demonstrates the importance of HEI to assess alignment with dietary guidance and investigate the relationship between diet quality and health outcomes across a variety of research settings. Information on the HEI is maintained on both the CNPP site (cnpp.usda.gov) as well as the National Cancer Institute site (www.epi.grants.cancer.gov/hei/). The National Cancer Institute dedicates pages for HEI Tools for Researchers, which describe the basic steps for calculating HEI component and total scores and further details for calculating scores for different types of research questions. The CNPP site includes technical reports, updated population level HEI scores for different age groups, and fact sheets that have been developed for each version of the HEI. The breadth of current HEI applications is being used to inform the development of new resources for researchers that will accompany the release of the HEI-2015 later this year. As the number of studies and scope of applications grows, so will our understanding of the far-reaching impact of diet quality on health outcomes.