The Healthy Eating Index helps determine the answer
ElsevierDietary risk factors are among the key contributors to mortality
and morbidity in the United States and globally, and there is increasing
emphasis on understanding the influence of total diet quality and overall
dietary patterns rather than single aspects of what we eat and drink.
In order to evaluate the quality of what people eat and drink,
researchers often rely on recommendations such as the Dietary Guidelines for
Americans (DGA).
In the latest issue of the Journal of the Academy of Nutrition and Dietetics,
leading nutrition experts describe and evaluate the latest version of the
Healthy Eating Index (HEI), which has been issued to correspond to the
2015-2020 Dietary Guidelines for Americans.
The
DGA are updated every five years, leading to changes in emphasis and
quantification, as the evidence on healthy eating evolves over time.
Likewise, a new HEI is issued to correspond to each new edition
of the DGA and to reflect these changes.
The HEI is a measure of diet quality, independent of quantity,
that can be used at various levels of the food stream, including the national
food supply, the community food environment (e.g., foods available at a school
or a fast food menu), and food intakes among the population.
The HEI score can be used to evaluate how healthy the American diet is in relation to federal dietary guidance.
It has been applied by researchers to describe diet quality
among the US population, as well as population subgroups such as Mexican
Americans, children, and cancer survivors.
It has also been used to evaluate the quality of food offerings
across the food stream, including the US food supply, restaurant menus, grocery
store circulars, and Federal food distribution programs.
"Tracking
quality at these different levels is critical since we are increasingly
recognizing the power of the food environment on eating behavior. That is,
individuals cannot be expected to make healthy choices if those options are not
readily available in the home, at work, at school, and in the community,"
comments Jill Reedy, PhD, MPH, RD, Program Director at the Risk Factor
Assessment Branch, Epidemiology and Genomics Research Program, Division of
Cancer Control and Population Sciences, National Cancer Institute, National
Institutes of Health, Bethesda, MD, USA, and co-author of the papers in this
issue.
The
latest HEI was developed through a collaboration between researchers at the
National Cancer Institute (NCI) and the United States Department of
Agriculture's (USDA) Center for Nutrition Policy and Promotion (CNPP). A trio
of papers in this special issue introduce the new HEI and describe differences
compared to the 2010 and 2005 editions, evaluate the properties of the HEI-2015
for assessing dietary quality, and discuss its applications.
Update
The
first paper outlines the steps taken to update the most recent version of the
HEI and prepare an HEI-2015 scoring system to reflect compliance with the
2015-2020 DGA food and nutrient recommendations.
"The Dietary Guidelines for Americans evolve incrementally
over time based on scientific evidence, and updates to the HEI are designed to
capture that evolution," explains Susan M. Krebs-Smith, PhD, MPH, Risk
Factor Assessment Branch, Epidemiology and Genomics Research Program, Division
of Cancer Control and Population Sciences, National Cancer Institute, National
Institutes of Health, Bethesda MD, USA.
The
2015 edition has 13 components, each reflecting an important aspect of diet
quality as per the DGA. Dr. Krebs-Smith and colleagues describe each of the
HEI-2015's constituent food and nutrient categories, as well as its 100-point
scoring system, including referent standards for each component of the total
score.
Since the 2005 version, the HEI has been based on densities
(e.g., amounts per 1000 kcal), rather than absolute amounts, and relies on a
common set of standards that are applicable across individuals and settings.
Notable differences compared to the previous edition are that saturated fat and added sugars are each separately tracked, and excessive alcohol contribution to energy is not captured separately. This new version also incorporates modifications to the scoring procedures for legumes.
Notable differences compared to the previous edition are that saturated fat and added sugars are each separately tracked, and excessive alcohol contribution to energy is not captured separately. This new version also incorporates modifications to the scoring procedures for legumes.
Evaluation
In
the second paper, Jill Reedy, PhD, MPH, RD, and colleagues report on testing of
the index's validity and reliability.
Known high-quality sample menus from a variety of organizations such as the National Heart, Lung, and Blood Institute (Dietary Approaches to Stop Hypertension [DASH] diet), US Department of Agriculture (USDA), Harvard Medical School (Healthy Eating Guide), and the American Heart Association (AHA) (No-Fad Diet) were scored using the HEI standards. These menus all achieved high scores, ranging from 88 to 100 points.
Known high-quality sample menus from a variety of organizations such as the National Heart, Lung, and Blood Institute (Dietary Approaches to Stop Hypertension [DASH] diet), US Department of Agriculture (USDA), Harvard Medical School (Healthy Eating Guide), and the American Heart Association (AHA) (No-Fad Diet) were scored using the HEI standards. These menus all achieved high scores, ranging from 88 to 100 points.
At
the next level of testing, data from the Centers for Disease Control and
Prevention's National Health and Nutrition Examination Survey (NHANES) were
used to compare HEI-2015 scores across population subgroups to examine if
meaningful differences could be detected.
Average HEI-2015 scores and ranges demonstrated reasonable variation across the subgroups examined, including groups differentiated by age, gender, and smoking status.
Results suggested that the index reflects the many dimensions of dietary guidance. As a final assessment, datasets from the NIH-AARP Diet and Health Study were examined and showed that individuals in the highest quintiles of HEI-2015 scores had a 13-23 percent decreased risk of all-cause, cancer, and cardiovascular disease mortality.
Average HEI-2015 scores and ranges demonstrated reasonable variation across the subgroups examined, including groups differentiated by age, gender, and smoking status.
Results suggested that the index reflects the many dimensions of dietary guidance. As a final assessment, datasets from the NIH-AARP Diet and Health Study were examined and showed that individuals in the highest quintiles of HEI-2015 scores had a 13-23 percent decreased risk of all-cause, cancer, and cardiovascular disease mortality.
"These
analyses demonstrated evidence supportive of validity and reliability for the
HEI-2015, as has been shown in earlier work with the HEI-2005 and
HEI-2010," notes Dr. Reedy. "However, limitations in the HEI as well
as those inherent to dietary intake data more broadly should be considered in
any application of the index."
Applications
The
third paper examines potential applications of the HEI-2015 in surveillance,
epidemiology, and community intervention research. Lead investigator Sharon I.
Kirkpatrick, PhD, MHSc, RD, Associate Professor, School of Public Health and
Health Systems, University of Waterloo, Waterloo, ON, Canada, and colleagues
outline approaches to calculating scores and review their suitability for
research questions related to monitoring eating patterns, understanding
associations between eating patterns and health/disease, and evaluating dietary
interventions.
The
focus of this paper is on the use of the HEI for cases in which dietary intake
data are available for characterizing diet quality for groups of individuals
sampled from the population.
Further development of methods for calculating the HEI for
individuals will help advance our knowledge on diet quality. "The use of
the most appropriate approach to calculating HEI scores for a given purpose can
help build a stronger literature on the influence of dietary quality on health
and disease risk, helping to inform future policies and programs to support
health," comments Dr. Kirkpatrick.
In
an accompanying editorial, Barbara Millen, DrPH, MPH, RD, FADA, Millennium
Prevention, Inc., and Boston Nutrition Foundation, Inc., Westwood, MA, USA, and
Chairman of the 2015 Dietary Guidelines Advisory Committee, points out the
growing use of web and mobile platforms and apps in clinical and community
settings for purposes such as diet and exercise behavior monitoring.
She forecasts a bright future for integrating new methods of
nutritional risk assessment, such as the HEI-2015, with advanced analytics and
innovative web and mobile technologies.
According
to Dr. Millen, "The evidence base is stronger than ever before linking the
'total diet' -- its dietary patterns, nutrient density, and overall quality --
to health promotion and disease prevention across the human life span. The work
of these investigators will hopefully inspire other researchers and nutrition
professionals to utilize the HEI-2015 broadly and establish other
evidence-based innovations that fully embrace the 2015-2020 DGA's five
cornerstone guidelines, and advance research and practice in clinical, public
health and consumer settings."