EURRECA—Estimating Zinc Requirements for Deriving Dietary Reference Values

Abstract

Zinc was selected as a priority micronutrient for EURRECA, because there is significant heterogeneity in the Dietary Reference Values (DRVs) across Europe. In addition, the prevalence of inadequate zinc intakes was thought to be high among all population groups worldwide, and the public health concern is considerable. In accordance with the EURRECA consortium principles and protocols, a series of literature reviews were undertaken in order to develop best practice guidelines for assessing dietary zinc intake and zinc status. These were incorporated into subsequent literature search strategies and protocols for studies investigating the relationships between zinc intake, status and health, as well as studies relating to the factorial approach (including bioavailability) for setting dietary recommendations. EMBASE (Ovid), Cochrane Library CENTRAL and MEDLINE (Ovid) databases were searched for studies published up to February 2010 and collated into a series of Endnote databases that are available for the use of future DRV panels. Meta-analyses of data extracted from these publications were performed where possible in order to address specific questions relating to factors affecting dietary recommendations. This review has highlighted the need for more high quality studies to address gaps in current knowledge, in particular the continued search for a reliable biomarker of zinc status and the influence of genetic polymorphisms on individual dietary requirements. In addition, there is a need to further develop models of the effect of dietary inhibitors of zinc absorption and their impact on population dietary zinc requirements.

Scientific Opinion on Dietary Reference Values for zinc

“…There are no known genotypes that would affect the estimation of DRVs for zinc. Significant results for altered putative zinc biomarkers in groups of people with differing gene variants have been documented by Lowe et al (2013).…”

“…The eligibility criteria were the following: studies of healthy adults, whole-day isotope studies of true zinc absorption, reporting measurements of TDZ, and total dietary phytate (TDP) and TAZ. No extensive literature search was performed in addition to that performed by the EURopean micronutrient RECommendations Aligned (EURRECA) network on factors affecting zinc bioavailability (Lowe et al, 2013); relevant publications were identified through knowledge of the existing work of the small number of investigators in this field of research and ongoing monitoring of the new literature. All the data came from research groups having extensive experience with the application of isotope tracer methods to the study of zinc absorption.…”

“…A systematic literature search and review for studies addressing zinc intake and health relationships was done by EURRECA; many studies were retrieved that addressed the relationship between zinc intake and outcomes such as cognitive and immune function, depression, anorexia, diabetes mellitus, ischaemic heart disease and cancer in adults. The authors concluded that studies were heterogeneous in their methodological approaches and outcomes assessed (Lowe et al, 2013). The Panel concludes that the available evidence on zinc intake and health outcomes cannot be used for setting DRVs for zinc.…”

EURRECA—Evidence-Based Methodology for Deriving Micronutrient Recommendations

“…Micronutrient-specific results of the systematic reviews can be found elsewhere in this issue (Cashman and Kiely, 2013;Hoey et al, 2013;Hurst et al, 2013;Lowe et al, 2013;Ristic-Medic et al, 2013). The quantitative methodology underlying these reviews is explained and illustrated in Activities 5, 6 and 7.…”

“…Using a similar systematic review methodology to that described above, specifically designed search strategies were tailored for each micronutrient followed by screening and data extraction. Details on the results of the systematic reviews and meta-analysis can be found elsewhere in this issue (Cashman and Kiely, 2013;Hoey et al, 2013;Hurst et al, 2013;Lowe et al, 2013;Ristic-Medic et al, 2013). Further details on the methodological approach to summarising and interpreting the data, and integrating the evidence can be found in Activities 5 and 6 respectively.…”