Food rating systems, diet quality, and health

Eileen Kennedy

The issue of nutrient density is not new. Almost 30 yearsago, researchers described ways to measure a “nutritious”food.1 Indeed, the first regulation to set standards foritems sold in competition with school meals in the 1980swas based on a nutrient density approach. However, therehas been a renewed emphasis on nutrient density as away to rate foods and as a way to promote more healthfuleating in the general population. This has partly beensparked by the 2005 Dietary Guidelines for Americans.2

For example,“get the most nutrients out of your calories”and “make smart choices for every good group” are state-ments that come directly out of the Dietary GuidelinesAdvisory Committee report.2 Unfortunately, nutrientdensity is not a concept that is clearly understood by theconsumer. Thus, the article by Drewnowski and Fulgoniin this issue is relevant and timely.3

In recent years there has been a proliferation of foodrating systems developed either by governments, retailsupermarkets, or individual food companies. A numberof these are described in detail by the two authors.3 Mostrecently the Food and Drug Administration (FDA) hasexpressed an interest in exploring the possibility of intro-ducing a universal, front-of-package labeling system oricon to help consumers select more nutritious foods.An opinion piece in the popular press highlights theFDA’s efforts and concludes,“. . . anything that eliminatesconfusion and promotes healthier eating would beworth the effort” (http://blogs.usatoday.com/oped/2007/09/good-enough-to-.html).

The concerns about increasing nutrient-dense foodsin the diet are not unique to the United States. The Euro-pean Union is also exploring standards for devising arating system for foods. Globally, the International Unionof Nutrition Sciences (IUNS) has established a task forceto develop a food rating system that could apply to a widevariety of countries and cultural settings. This worldwideinterest in developing and implementing a food qualityscore to guide dietary choices is driven, in large part, bythe emerging problems of chronic disease. Dubbed the“Double Burden of Disease”, the changing profile of

at-risk populations worldwide shows that the classicalproblems of nutrient deficits and undernutrition arenow found side-by-side with diet-related problems ofoverweight, obesity, diabetes, heart diseases, and someforms of cancer. Thus, policy makers are increasinglyemphasizing that both dietary quantity and quality areimportant.

The article by Drewnowski and Fulgoni3 grappleswith some critical technical issues as it describes chal-lenges to developing a science-based system for assessingthe nutrient density of a food, such as which nutrients toinclude and the most appropriate standards against whichto measure the nutrients. However, there are some addi-tional overarching concepts that deserve more discus-sion. As the authors appropriately note, the process ofcomparing one algorithm for measuring nutrient densityto another, as has been done in the past, is an unsatisfac-tory way to assess the validity of any particular method.Rather, there is an imperative need for an independentsystem for validating approaches to nutrient density. Animplicit assumption in a nutrient density approach tochoosing foods is that the total diet of a person will ulti-mately improve. Therefore, the validation of nutrientdensity against an independent standard such as theUSDA Healthy Eating Index is warranted. An even betterapproach to validating different scoring methods wouldbe to link the selection of more nutrient-dense foods tohealth outcomes. These types of data are typically notavailable.

The data presented by Drewnowski and Fulgoni3

show clearly that fruits and vegetables tend to be the foodsand food groups that are the most nutrient dense. Acynical reviewer might ask, “What’s new?” since con-sumption data in the United States have confirmed foryears that fruit and vegetable intake in the American dietis suboptimal.4 Thus, a second overarching theme thatmust be considered seriously is the extent to which anyfood scoring system will positively influence food choices.A key assumption is that the promotion of nutrient-densefoods – in this case thorough a scoring system – will

Affiliation: E Kennedy is with the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy, Boston, Massachusetts 02111,USA.

Correspondence: E Kennedy, Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy, 150 Harrison Avenue Boston, MA02111, USA. E-mail: eileen.kennedy@tufts.edu, Phone: +1-617-636-3702

Invited Commentary

doi:10.1111/j.1753-4887.2007.00002.xNutrition Reviews® Vol. 66(1):21–22 21

improve dietary patterns and/or health. This is logical toassume yet there are no actual data pointing to theseeffects. Therefore, there is an imperative need forresearchers to ascertain the effect of food rating systemson the diet quality and health of consumers. Researchershave long known that the major determinants of foodchoices are taste, price, and convenience.5 Whether pro-motion of a specific food rating system will significantlyinfluence food choices and food consumption needs to bedetermined empirically. The authors emphasize in theirarticle that a nutrient density approach can be a valuabletool for improving dietary behaviors.3 Let me add to thisobservation, “only if the food rating system is used con-sistently by the consumer”.

REFERENCES

1. Zelman K, Kennedy E. Naturally nutrient rich: putting morepower on the Americans’ plates. Nutr Today 2005;40:60–68.

2. United States Department of Health and Human Services/Department of Agriculture. Dietary Guidelines for Americans,2005. Available at: http://www.health.gov/dietaryguidelines/dga2005/document/default.htm. Accessed: 4 November 2007.

3. Drewnowski A, Fulgoni III V. Nutr Rev 2007;65:(present issue).4. Basiotis PP, Carlson A, Gerrior SA, Juan WY, Lino M. The

Healthy Eating Index: 1999–2000. Available at: http:/www.cnpp.usda.gov/publications/HEI/HEI99-00report.pdf.Accessed: 4 November 2007.

5. Kennedy E, Deckelbaum R. The Nations Nutrition. Washington,DC: ILSI Press; 2007.

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