Skip to main content

Diet quality – what is it and does it matter?

  • Annika Wirt (a1) and Clare E Collins (a1)

Measures of diet quality have evolved with a number of scoring indices currently in use. They are increasingly being used to examine epidemiological associations between dietary intake and nutrition-related health outcomes. The present review aims to describe current diet quality tools and their applications, and to examine the relationship between diet quality and morbidity and mortality.


A search was conducted of MEDLINE, Cochrane, EMBASE, CINAHL and ProQuest electronic databases. Inclusion criteria were: English language; published from 2004 on; conducted in adult populations; longitudinal/cohort/case–control or cross-sectional study; included a theoretically defined measure of diet quality.


A total of twenty-five indices of overall diet quality and/or variety were found, with components ranging from nutrients only to adherence to recommended food group servings, to variety within healthful food groups. The majority of studies reviewed had methodological weaknesses but demonstrated that higher dietary quality was consistently inversely related to all-cause mortality, with a protective effect of moderate magnitude. The associations were stronger for men and for all-cause and CVD mortality.


The limitations of both the indices and the studies that use them need to be considered when interpreting and comparing results. However, diet quality indices do appear to be able to quantify risk of some health outcomes, including biomarkers of disease and risk of CVD, some cancers and mortality. Further research is needed to improve the validity of these tools and to adapt them for use in clinical dietetic practice.

    • Send article to Kindle

      To send this article to your Kindle, first ensure is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the or variations. ‘’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Diet quality – what is it and does it matter?
      Available formats
      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Diet quality – what is it and does it matter?
      Available formats
      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Diet quality – what is it and does it matter?
      Available formats
Corresponding author
*Corresponding author: Email
Hide All
1.Kant, A (1996) Indexes of overall diet quality. J Am Diet Assoc 96, 785791.
2.Kant, A (2004) Dietary patterns and health outcomes. J Am Diet Assoc 104, 615635.
3.Waijers, P, Feskens, E & Ocke, M (2007) A critical review of predefined diet quality scores. Br J Nutr 97, 219231.
4.Joanna Briggs Institute (2003) Observational critical appraisal form 4.2. (accessed December 2008).
5.Joanna Briggs Institute (2003) Data extraction form 5. (accessed December 2008).
6.Hann, C, Rock, C, King, I & Drewnowski, A (2001) Validation of the Healthy Eating Index with use of plasma biomarkers in a clinical sample of women. Am J Clin Nutr 74, 479486.
7.Huijbregts, P, Feskens, E, Rasanen, L, Fidanza, F, Nissinen, A, Menotti, A & Kromhout, D (1997) Dietary pattern and 20 year mortality in elderly men in Finland, Italy, and the Netherlands: longitudinal cohort study. BMJ 315, 1317.
8.Osler, M, Heitmann, B, Gerdes, L, Jorgensen, L & Schroll, M (2001) Dietary patterns and mortality in Danish men and women: a prospective observational study. Br J Nutr 85, 219225.
9.Kant, A, Schatzkin, A, Graubard, B & Schairer, C (2000) A prospective study of diet quality and mortality in women. JAMA 283, 21092115.
10.Seymour, J, Calle, E, Flagg, E, Coates, R, Ford, E & Thun, M (2003) Diet quality index as a predictor of short-term mortality in the American Cancer Society cancer prevention study II nutrition cohort. Am J Epidemiol 157, 980988.
11.Fitzgerald, A, Dewar, R & Veugelers, P (2002) Diet quality and cancer incidence in Nova Scotia, Canada. Nutr Cancer 43, 127132.
12.Trichopoulou, A, Kouris-Blazos, A, Wahlqvist, M, Gnardellis, C, Lagiou, P, Polychronopoulos, E, Vassilakou, T, Lipworth, L & Trichopoulos, D (1995) Diet and survival in elderly people. BMJ 311, 14571460.
13.Weinstein, S, Vogt, T & Gerrior, S (2004) Healthy Eating Index Scores are associated with blood nutrient concentrations in the Third National Health and Nutrition Examination Survey. J Am Diet Assoc 104, 576584.
14.Gerber, M, Scali, J, Michaud, A, Durand, M, Astre, C, Dallongeville, J & Romon, M (2000) Profiles of a healthful diet and its relationship to biomarkers in a population sample from Mediterranean southern France. J Am Diet Assoc 100, 11641171.
15.Toft, U, Kristoffersen, L, Lau, C, Borch-Johnsen, K & Jorgensen, T (2007) The Dietary Quality Score: validation and association with cardiovascular risk factors: the Inter99 study. Eur J Clin Nutr 61, 270278.
16.Kim, S, Haines, P, Seiga-Riz, A & Popkin, B (2003) The Diet Quality Index–International (DQI-I) provides an effective tool for cross-national comparison of diet quality as illustrated by China and the United States. J Nutr 133, 34763484.
17.Trichopoulou, A, Costacou, T, Bamia, C & Trichopoulos, D (2003) Adherence to a Mediterranean diet and survival in a Greek population. N Engl J Med 348, 25992608.
18.Lagiou, P, Trichopoulos, D, Sandin, S, Lagiou, A, Mucci, L, Wolk, A, Weiderpass, E & Adami, H (2006) Mediterranean dietary pattern and mortality among young women: a cohort study in Sweden. Br J Nutr 96, 384392.
19.Osler, M & Schroll, M (1997) Diet and mortality in a cohort of elderly people in a North European community. Int J Epidemiol 26, 155159.
20.Knoops, K, Groot de, L, Fidanza, F, Alberti-Fidanza, A, Kromhout, D & van Staveren, WA (2006) Comparison of three different dietary scores in relation to 10-year mortality in elderly European subjects: the HALE project. Eur J Clin Nutr 60, 746755.
21.Fung, T, Hu, F, McCullough, M, Newby, P, Willett, W & Holmes, M (2006) Diet quality is associated with the risk of estrogen receptor-negative breast cancer in postmenopausal women. J Nutr 136, 466472.
22.McCullough, M, Feskanich, D, Stampfer, M, Giovannucci, E, Rimm, E, Hu, F, Spiegelman, D, Hunter, D, Colditz, G & Willett, W (2002) Diet quality and major chronic disease risk in men and women: moving toward improved dietary guidance. Am J Clin Nutr 76, 12611271.
23.McCullough, M, Feskanich, D, Rimm, E, Giovannucci, E, Ascherio, A, Variyan, J, Spiegelman, D, Stampfer, M & Willett, W (2000) Adherence to the Dietary Guidelines for Americans and risk of major chronic disease in men. Am J Clin Nutr 72, 12231231.
24.McCullough, M, Feskanich, D, Stampfer, M, Rosner, B, Hu, F, Hunter, D, Variyan, J, Colditz, G & Willett, W (2000) Adherence to the Dietary Guidelines for Americans and risk of major chronic disease in women. Am J Clin Nutr 72, 12141222.
25.Fernandez, E, Negri, E, La Vecchia, C & Franceschi, S (2000) Diet diversity and colorectal cancer. Prev Med 31, 1114.
26.Fernandez, E, D’Avanzo, B, Negri, E, Franceschi, S & La Vecchia, C (1996) Diet diversity and the risk of colorectal cancer in Northern Italy. Cancer Epidemiol Biomarkers Prev 5, 433436.
27.Slattery, M, Berry, T, Potter, J & Caan, B (1997) Diet diversity, diet composition, and risk of colon cancer (United States). Cancer Causes Control 8, 872882.
28.Harnack, L, Nicodemus, K, Jacobs, D & Folsom, A (2002) An evaluation of the Dietary Guidelines for Americans in relation to cancer occurrence. Am J Clin Nutr 76, 889896.
29.Huijbregts, P, Feskens, E, Rasanen, L, Fidanza, F, Alberti-Fidanza, A, Nissinen, A & Giampaoli, S (1998) Dietary patterns and cognitive function in elderly men in Finland, Italy and the Netherlands. Eur J Clin Nutr 52, 826831.
30.Osler, M, Andreasen, A, Heitmann, B, Hiodrup, S, Gerdes, U, Jorgensen, L & Schroll, M (2002) Food intake patterns and risk of coronary heart disease: a prospective cohort study examining the use of traditional scoring techniques. Eur J Clin Nutr 56, 568574.
31.Bazelmans, C, De Henauw, S, Matthys, C, Dramaix, M, Kornitzer, M, De Backer, G & Leveque, A (2006) Healthy Food and Nutrient Index and all cause mortality. Eur J Epidemiol 21, 145152.
32.Mai, V, Kant, A, Flood, A, Lacey, JJ, Schairer, C & Schatzkin, A (2005) Diet quality and subsequent cancer incidence and mortality in a prospective cohort of women. Int J Epidemiol 34, 5460.
33.Michels, K & Wolk, A (2002) A prospective study of variety of healthy foods and mortality in women. Int J Epidemiol 31, 847854.
34.Murphy, S, Davis, M, Neuhaus, J & Lein, D (1996) Dietary quality and survival among middle-aged and older adults in the NHANES I Epidemiologic Follow-Up Study. Nutr Res 16, 16411650.
35.Panagiotakos, D, Pitsavos, C & Stefanadis, C (2006) Dietary patterns: a Mediterranean diet score and its relation to clinical and biological markers of cardiovascular disease risk. Nutr Metab Cardiovasc Dis 16, 559568.
36.McCullough, M & Willett, W (2006) Evaluating adherence to recommended diets in adults: the Alternate Healthy Eating Index. Public Health Nutr 9, 152157.
37.Alberti-Fidanza, A, Fidanza, F, Chiuchiù, MP, Verducci, G & Fruttini, D (1999) Dietary studies on two rural Italian population groups of the Seven Countries Study. 3. Trends of food and nutrient intake from 1960 to 1991. Eur J Clin Nutr 53, 854860.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Public Health Nutrition
  • ISSN: 1368-9800
  • EISSN: 1475-2727
  • URL: /core/journals/public-health-nutrition
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed