Validity of a questionnaire to assess fruit and vegetable intake in adults

Ása Guðrún Kristjansdottir, L. F. Andersen, J. Haraldsdottir, M. D.V. de Almeida, I. Thorsdottir*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)


Objective: To validate a method for assessing fruit and vegetable intake among adults in a population of low intake. The method assesses mean intake and ranks individuals by their usual intake. Design: A precoded fruit and vegetable Questionnaire included a 24-h recall and a food frequency. The participants filled in the Questionnaire, a week later they started a 7-day food record, 1-day weighed record and 6 days using household measures. Subjects: Following advertisements 40 participants were recruited, 36 returned food records(mean age = 37 years). Results: No difference was observed between the average intake yielded by the 24-h recall and that from the 1-day weighed food record of fruits or vegetables. Correlation coefficients between results from the food frequency questionnaire and the 7-day food records were 0.45 (P=007) for vegetables, 0.63 (P<0.001) for fruits and 0.73 (P<0.001) for fruits and vegetables combined. Cross-classification into quartiles showed that the proportion of participants in the same or the adjacent quartile of the intake distribution were 94% for fruit intake and 80% for vegetable intake. Registered intake of fruits and vegetables was higher the first 4 days of the record than the last 3 days (P=0.002). The 4-day food record correlated with the food frequency questionnaire in similar manner as the 7-day record. Conclusion: The present study indicates that the precoded 24-h recall may be valuable tool for measuring average intake of fruits and vegetables among adults in a population of low intake. Moreover, the food frequency questionnaire was valid for ranking individuals according to their usual intake. A 4-day food record might be sufficient when validating food frequency questionnaires for fruits and vegetables.

Original languageEnglish
Pages (from-to)408-415
Number of pages8
JournalEuropean Journal of Clinical Nutrition
Issue number3
Publication statusPublished - Mar 2006

Bibliographical note

Funding Information:
This study has been carried out with financial support from the Commission of the European Communities, specific RTD programme ‘Quality of Life and Management of Living Resources’, QLK1-2001-00547 ‘Promoting and Sustaining Health through Increased Vegetable and Fruit Consumption among European Schoolchildren’ (Pro Children). It does not necessarily reflect its views and in no way anticipates the Commission’s future policy in this area.

Other keywords

  • Fruit
  • Iceland
  • Questionaire
  • Validity
  • Vegetable


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