a1 Department of Clinical Sciences, University of Las Palmas de Gran Canaria, PO Box 550, 35080 Las Palmas de Gran Canaria, Spain
a2 Division of General Internal and Geriatric Medicine, Department of Internal Medicine, School of Medicine of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes, 3900 Ribeirão Preto, SP, Brazil
a3 Community Nutrition Research Centre of the Nutrition Research Foundation, University of Barcelona Science Park, Baldiri Reixac 4, 08028 Barcelona, Spain
The EURRECA Network of Excellence is working towards the development of aligned micronutrient recommendations across Europe. The purpose of the present study was to define how to identify dietary intake validation studies in adults pertaining to vitamins. After establishing a search strategy, we conducted a MEDLINE and EMBASE literature review. A scoring system was developed to rate the quality of each validation study according to sample size, statistical methods, data collection procedure, seasonality and vitamin supplement use. This produced a quality index with possible scores obtained ranging from 0·5 to 7. Five thousand four-hundred and seventy-six papers were identified. The numbers meeting the inclusion criteria were: for vitamin A, 76; vitamin C, 108; vitamin D, 21; vitamin E, 75; folic acid, 47; vitamin B12, 19; vitamin B6, 21; thiamine, 49; riboflavin, 49; and niacin, 32. The most frequently used method to ascertain dietary intake was the Food Frequency Questionnaire (FFQ), whereas dietary records (DR) and 24-h recalls were the most used reference methods. The correlation coefficients (CC) between vitamin intakes estimated by FFQ and the reference method were weighted according to the study's quality index and ranged from 0·41 to 0·53 when the reference method was the DR and from 0·43 to 0·67 when the reference was 24-h recalls. A minority of studies (n 33) used biomarkers for validation and in these the CC ranged from 0·26 to 0·38. The FFQ is an acceptable method of assessing vitamin intake. The present review provides new insights regarding the characteristics that assessment methods for dietary intake should fulfil.
(Received April 05 2009)
(Revised September 28 2009)
(Accepted October 15 2009)
On behalf of EURRECA's RA.1.1 “Intake Methods” members: Serra-Majem L (Coordinator), Cavelaars A, De Groot L, De Vries J, Dhonukshe-Rutten R, Doreste JL, Frost-Andersen L, García-Álvarez A, Glibetic M, Gurinovic M, Henríquez-Sánchez P, Naska A, Ngo J, Novakovic R, Ortiz-Andrellucchi A, Øverby NC, Pijls L, Ranic M, Ribas-Barba L, Ristic-Medic D, Román-Viñas B, Ruprich J, Saavedra-Santana P, Sánchez-Villegas A, Tabacchi G, Tepsic J, Trichopoulou A, van 't Veer P, Vucic V, Wijnhoven TMA.
Abbreviations: CC, correlation coefficients; DR, dietary records