Dietary Indicators for Assessing the Adequacy of Population Zinc Intakes

The assessment of dietary zinc intakes is an important component of evaluating the risk of zinc deficiency in populations, and for designing appropriate food-based interventions, including fortification, to improve zinc intakes. The prevalence of inadequate zinc intakes can describe the relative magnitude of the risk of zinc deficiency in the population and identify subpopulations at elevated risk. As a cornerstone to evaluating the adequacy of population zinc intakes globally, a set of internationally appropriate dietary reference intakes must be defined. The World Health Organization/Food and Agriculture Organization/International Atomic Energy Agency (WHO/FAO/IAEA) and the Food and Nutrition Board/US Institute of Medicine (FNB/IOM) have presented estimated average requirements (EAR) for dietary zinc intake, and, more recently, the International Zinc Nutrition Consultative Group (IZiNCG) presented a revised set of recommendations for international use. A prevalence of inadequate zinc intakes greater than 25% is considered to represent an elevated risk of population zinc deficiency. As the requirement estimates are derived from smaller, clinical studies and, for children, most components of the estimates are extrapolated from data for adults, it was desirable to evaluate their internal validity. The estimated physiological requirements for adult men and women appear to adequately predict zinc status as determined by biochemical indicators of status and/or zinc balance. With the use of data from available studies, the reported prevalence of low serum zinc concentration and the estimated prevalence of inadequate zinc intakes predict similar levels of risk of zinc deficiency, particularly among pregnant and nonpregnant women. Conformity between these two indicators is less consistent for children, suggesting that further data and/or direct studies of zinc requirements among children are needed.

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Conclusions of the Joint WHO/UNICEF/IAEA/IZiNCG Interagency Meeting on Zinc Status Indicators

Food and Nutrition Bulletin ◽

10.1177/15648265070283s306 ◽

2007 ◽

Vol 28 (3_suppl3) ◽

pp. S480-S484 ◽

Cited By ~ 129

Author(s):

Bruno de Benoist ◽

Ian Darnton-Hill ◽

Lena Davidsson ◽

Olivier Fontaine ◽

Christine Hotz

Keyword(s):

Zinc Deficiency ◽

Serum Zinc ◽

Time Of Day ◽

World Health ◽

Zinc Status ◽

Energy Agency ◽

Zinc Nutrition ◽

Health Organization ◽

Working Group Meeting ◽

Height For Age

Zinc deficiency is an important cause of morbidity in developing countries, particularly among young children, yet little information is available on the global prevalence of zinc deficiency. A working group meeting was convened by the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), the International Atomic Energy Agency (IAEA), and the International Zinc Nutrition Consultative Group (IZiNCG) to review methods of assessing population zinc status and provide standard recommendations for the use of specific biochemical, dietary, and functional indicators of zinc status in populations. The recommended biochemical indicator is the prevalence of serum zinc concentration less than the age/sex/time of day-specific cutoffs; when the prevalence is greater than 20%, intervention to improve zinc status is recommended. For dietary indicators, the prevalence (or probability) of zinc intakes below the appropriate estimated average requirement (EAR) should be used, as determined from quantitative dietary intake assessments. Where the prevalence of inadequate intakes of zinc is greater than 25%, the risk of zinc deficiency is considered to be elevated. Previous studies indicate that stunted children respond to zinc supplementation with increased growth. When the prevalence of low height-for-age is 20% or more, the prevalence of zinc deficiency may also be elevated. Ideally, all three types of indicators would be used together to obtain the best estimate of the risk of zinc deficiency in a population and to identify specific subgroups with elevated risk. These recommended indicators should be applied for national assessment of zinc status and to indicate the need for zinc interventions. The prevalence of low serum zinc and inadequate zinc intakes may be used to evaluate their impact on the target population's zinc status.

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A Review of Dietary Zinc Recommendations

Food and Nutrition Bulletin ◽

10.1177/0379572116652252 ◽

2016 ◽

Vol 37 (4) ◽

pp. 443-460 ◽

Cited By ~ 32

Author(s):

Rosalind S. Gibson ◽

Janet C. King ◽

Nicola Lowe

Keyword(s):

Food Safety ◽

Life Stage ◽

World Health ◽

Institute Of Medicine ◽

Dietary Zinc ◽

Zinc Bioavailability ◽

Body Weights ◽

The Us ◽

Zinc Nutrition ◽

Health Organization

Background: Large discrepancies exist among the dietary zinc recommendations set by expert groups. Objective: To describe the basis for the differences in the dietary zinc recommendations set by the World Health Organization, the US Institute of Medicine, the International Zinc Nutrition Consultative Group, and the European Food Safety Agency. Methods: We compared the sources of the data, the concepts, and methods used by the 4 expert groups to set the physiological requirements for absorbed zinc, the dietary zinc requirements (termed estimated and/or average requirements), recommended dietary allowances (or recommended nutrient intakes or population reference intakes), and tolerable upper intake levels for selected age, sex, and life-stage groups. Results: All 4 expert groups used the factorial approach to estimate the physiological requirements for zinc. These are based on the estimates of absorbed zinc required to offset all obligatory zinc losses plus any additional requirements for absorbed zinc for growth, pregnancy, or lactation. However, discrepancies exist in the reference body weights used, studies selected, approaches to estimate endogenous fecal zinc (EFZ) losses, the adjustments applied to derive dietary zinc requirements that take into account zinc bioavailability in the habitual diets, number of dietary zinc recommendations set, and the nomenclature used to describe them. Conclusions: Estimates for the physiological and dietary requirements varied across the 4 expert groups. The European Food Safety Agency was the only expert group that set dietary zinc recommendations at 4 different levels of dietary phytate for adults (but not for children) and as of yet no tolerable upper intake level for any life-stage group.

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Prevalence of zinc deficiency among primary school children in a poor peri-urban informal settlement in South Africa

Health SA Gesondheid ◽

10.4102/hsag.v15i1.433 ◽

2010 ◽

Vol 15 (1) ◽

Cited By ~ 4

Author(s):

Folake O. Samuel ◽

Abdulkadir A. Egal ◽

Wilna H. Oldewage-Theron ◽

Carin E. Napier ◽

Christine S. Venter

Keyword(s):

Social Sciences ◽

South Africa ◽

Zinc Deficiency ◽

Informal Settlement ◽

Serum Zinc ◽

Primary School Children ◽

World Health ◽

Food Sources ◽

Cross Sectional ◽

The Mean

This cross-sectional study assessed the risk of zinc deficiency in randomly selected children, aged between 7 and 11 years, living in a poor, peri-urban informal settlement in South Africa. Dietary intake of 149 respondents was evaluated by 24-hour recall and quantitative food frequency questionnaires. Anthropometric and biochemical indices of a subset of 113 were determined. Descriptive statistics, analysis of variance and Pearson correlations were computed using the Statistical Package for Social Sciences, version 14.0. Anthropometric data were analysed using the World Health Organization Anthro plus version 1.0.2 statistical software. Dietary data were analysed with FoodFinder® version 3. The mean age of the children was 9.0±1.1 years. Few zinc-rich sources appeared in the diet that was predominantly plant-based. Mean dietary zinc intake was 4.6±2.2 mg/day. The mean value of serum zinc was 66.4±21.5 µg/dL, with 46% of the children having values less than the 70 µg/dL cut-off. The findings indicate a high risk of zinc deficiency and suboptimal zinc status for the majority of this study population of children, possibly as a result of low consumption of food sources with high bioavailability of zinc, which invariably is a direct consequence of poverty and food insecurity.OpsommingDie doel van hierdie dwarsdeursnitstudie was die bepaling van die risiko van ’n sinktekort in ’n ewekansige steekproef van 7 tot 11 jaar-oue kinders, woonagtig in ’n arm, voorstedelike informele woonbuurt in Suid Afrika. Dieetinnames van 149 respondente is geëvalueer deur 24-uur herroep en kwantitatiewe voedselfrekwensie vraelyste. Antropometriese en biochemiese indikatore van ’n kleiner steekproef van 113 is ook bepaal. Beskrywende statistiek, analise van variansie en Pearsonkorrelasies is bepaal deur die Statistical Package for Social Sciences, uitgawe 14.0. Antropometriese data is geanaliseer deur die statistiese program, Anthro plus, uitgawe 1.0.2, van die Wêreld Gesondheid Organisasie. Dieetdata is met behulp van FoodFinder® uitgawe 3 geanaliseer. Die gemiddelde ouderdom van die kinders was 9.0±1.1 jaar. Min sinkryke voedselbronne is in die hoofsaaklik plantryke dieet waargeneem. Die gemiddelde sinkinname was 4.6±2.2 mg/dag en die gemiddelde serumsinkwaarde was 66.4±21.5 µg/dL, met 46% van die kinders se waardes onder die 70 µg/dL afsnypunt. Die bevindings dui op ’n hoë risiko vir sinktekort en suboptimale sinkstatus vir die meerderheid van hierdie kinders, moontlik as gevolg van die swak inname van voedselbronne met hoë biobeskikbare sink, wat gewoonlik ’n direkte gevolg van armoede en huishoudelike voedsel insekuriteit is.

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