Dietary assessment methods for intakes of iron, calcium, selenium, zinc and iodine

Abstract

The EURopean micronutrient RECommendations Aligned (EURRECA) Network of Excellence is working towards developing aligned micronutrient recommendations across Europe. The purpose of the present study was to conduct a review of methods used in validation studies carried out in adults assessing dietary intake of EURRECA priority minerals. A search strategy and inclusion criteria were defined and a scoring system was developed to rate the quality of each validation study that produced a quality index with possible scores obtained ranging from 0·5 to 7. A MEDLINE and EMBASE literature review was conducted. Articles/validation studies meeting the inclusion criteria included: 79/88 for Fe; 95/104 for Ca; 13/15 for Se; 29/30 for Zn; 7/9 for iodine. 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 study mineral intakes estimated by FFQ and the reference method were weighted according to the study's quality index and obtained acceptable to good ratings, ranging from 0·36 to 0·60 when the reference method was DR and from 0·41 to 0·58 when the reference was 24 h recalls. A minority of studies (n 9) used biomarkers for validation and among these, five included iodine obtaining a CC of 0·47. The FFQ was seen as a valid method for assessing mineral intake, particularly for Ca and, to a lower extent, for iodine and Zn. Se and Fe showed only acceptable correlations. The present review provides new insights regarding the characteristics that assessment methods for dietary mineral intakes should fulfil.

Selenium biochemistry and its role for human health

“…9 A number of approaches can be used to estimate the dietary intake of Se, ranging from direct analysis of composite food types, to indirect calculation using dietary or market basket surveys and food composition tables. 13 Notably, since the total concentration of Se in food strongly reflects the soil conditions, the dietary intake varies widely with geographical localization. 14 An additional crucial aspect is that food types provide Se in distinct combinations of chemical forms which in turn entail a different bioavailability of the element.…”

Validity and reproducibility of a food frequency questionnaire to assess food group intake in adolescents

“…The selection of an appropriate reference method is an essential element of the effective assessment of FFQs and research in this area is often hampered by the lack of a gold standard for dietary intake 18 . Furthermore, error detection methods should be as independent as possible 19,20 .…”

“…The main sources of error in FFQs are participant memory, the interpretation of questions, perception of serving sizes and the limitations imposed by a fixed list of food items. Open-ended diet records do not depend on memory and are likely to result in less correlated errors 1,18 . Nevertheless, keeping a diet record is a substantial burden on participants and often influences the respondent's diet.…”

EURRECA—Evidence-Based Methodology for Deriving Micronutrient Recommendations

“…Following EURRECA's in depth review of all available dietary assessment validation studies, which analysed the utility of a range of dietary micronutrient intake questionnaires (Henriquez-Sanchez et al, 2009;Ortiz-Andrellucchi et al, 2009a;Ortiz-Andrellucchi et al, 2009b;OrtizAndrellucchi et al, 2009c;Øverby et al, 2009;Serra-Majem et al, 2009c), it was concluded that a scoring system was required to facilitate straightforward evaluation of the reliability of FFQ data . validation studies assessed, which reported data from at least one vitamin were also categorised into three groups dependent on the reference method or gold standard applied in each case.…”