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Country Level Zinc Data

Estimating national risk of zinc deficiency: proxy indicators vs. plasma/serum zinc concentrations

Estimating national risk of zinc deficiency: proxy indicators vs. plasma/serum zinc concentrations

There is an urgent need for more and better data on the zinc status of vulnerable populations to effectively target and monitor zinc intervention programs.

Plasma/serum zinc concentration is endorsed as the best available biomarker of zinc status, particularly for assessing the risk of zinc deficiency in target population groups such as preschool-aged children and women of reproductive age. Given the scarcity of nationally representative PZC data, global estimates for the risk of zinc deficiency have been based on two proxy measures:

  • the amount of absorbable zinc in the national food supply, and

  • the prevalence of stunting among children under five.

The risk of zinc deficiency is considered to be elevated and a likely public health problem when the prevalence of inadequate absorbable zinc intakes is >25% and if stunting rates are >20%.

National risk of zinc deficiency based on the prevalence of childhood stunting and the estimated prevalence of inadequate zinc intake (Wessells & Brown, 2012)

National risk of zinc deficiency based on the prevalence of childhood stunting and the estimated prevalence of inadequate zinc intake (Wessells & Brown, 2012)

Wessels & Brown estimated the global prevalence of zinc deficiency:

  • Based on the Food and Agriculture Organization of the United Nations’ (FAO) Food Balance Sheets, at least 17% of the world’s population is at risk of inadequate zinc intake.

  • In 2011, 84 low-and middle-income countries (LMICs) with available data had a stunting prevalence >20% among children <5 years of age. Furthermore, 32 of these countries were identified as high risk based on both dietary intake and stunting.

However, comparisons with data from national surveys that have measured plasma or serum zinc concentration show that intake based on food balance sheets underestimate the risk of zinc deficiency. As seen in the map below, the prevalence of low plasma/serum zinc concentrations in young children was >20% in the majority of the surveys.

Percentage of pre-school children with low plasma or serum zinc concentrations. Map generated from data in the  World Health Organization’s Vitamin and Mineral Nutrition Information System Micronutrients Database.

Percentage of pre-school children with low plasma or serum zinc concentrations. Map generated from data in the World Health Organization’s Vitamin and Mineral Nutrition Information System Micronutrients Database.

Countries with population-level data on plasma/serum zinc concentrations

Countries with population-level data on plasma/serum zinc concentrations

IZiNCG keeps a global inventory of recently completed and upcoming national nutrition surveys measuring plasma/serum zinc concentrations. The countries and link to survey report are listed below.

In 2018, plasma/serum zinc was incorporated into WHO’s Micronutrient Database, which enables data visualization.

Afghanistan — National Nutrition Survey Afghanistan (2013) Survey Report
Azerbaijan — Nutrition Survey 2013 
Bangladesh — National Micronutrients Status Survey 2011-12 – Final Report+new data coming
Bolivia — data coming
Cambodia — The High Prevalence of Anemia in Cambodian Children and Women Cannot Be Satisfactorily Explained by Nutritional Deficiencies or Hemoglobin Disorders
Cameroon — Stunting Prevalence, Plasma Zinc Concentrations, and Dietary Zinc Intakes in a Nationally Representative Sample Suggest a High Risk of Zinc Deficiency among Women and Young Children in Cameroon
China — survey data (2013) for children 36-72 months available in National Risk of Zinc Deficiency as Estimated by National Surveys
Colombia —  Factores asociados a la deficiencia de zinc en niños colombianos; resultados de la Encuesta Nacional de Salud 2010; estudio transversal 
Ethiopia — Ethiopian National Micronutrient Survey Report, September 2016
Fiji   Impact of Iron Fortified Flour in Child Bearing Age (CBA) Women in Fiji 2010 Report
Guatemala — Encuesta Nacional de Micronutrientes 2009-2010
India — data coming
Kenya —  The Kenya National Micronutrient Survey 2011
Kuwait — Reference Ranges of Copper and Zinc and the Prevalence of Their Deficiencies in an Arab Population Aged 15-80 Years
Malawi — Malawi Micronutrient Survey Key Indicators Report 2015-16
Maldives — Project Report National Micronutrient Survey 2007 Republic of Maldives
Mexico — Anemia and iron, zinc, copper and magnesium deficiency in Mexican adolescents: National Health and Nutrition Survey 2006 ; Prevalence of Zinc Deficiency in Mexican Children and Women of Childbearing Age (abstract);  Iron, zinc, copper and magnesium nutritional status in Mexican children aged 1 to 11 years ; Iron, zinc, copper and magnesium deficiencies in Mexican adults from the National Health and Nutrition Survey 2006
Myanmar — Interim report launched February 2019
Nepal — Nepal National Micronutrient Status Survey
Nigeria — Nigeria Food Consumption and Nutrition Survey 2001-2003: Summary
Pakistan — Pakistan National Nutrition Survey 2018 - key findings report NEW
Philippines— 7th National Nutrition Survey, Philippines 2008: Serum Zinc Levels in Selected Filipino Population Groups
Senegal— Statut en Zinc des Enfants Senegalais et Evaluation de L’Utilisation de la Concentration Plasmatique en Zinc pour Tester L’Impact des Programmes de Fortification ; Adjusting Plasma Concentrations of Ferritin, Retinol, and Zinc Affect the Prevalence of Micronutrient Deficiencies in Children but Not in Women (abstract); 
South Africa — National Food Consumption Survey-Fortification Baseline (NFCS-FB-I): South Africa, 2005
Sri Lanka — National Nutrition and Micronutrient Survey – Part II: Iron, Zinc and Calcium Deficiency Among Children Aged 6-59 Months
Vietnam — Micronutrient Deficits Are Still Public Health Issues among Women and Young Children in Vietnam +new data coming

Plasma/serum zinc in national surveys - barriers and enablers

Plasma/serum zinc in national surveys - barriers and enablers

“Micronutrient deficiencies are estimated to impact a significant number of people around the world, but there remains far too little information on micronutrient status and deficiencies. More essential information and surveillance need to be gathered to make substantial progress on global targets.” 

Global Nutrition Report 2018

There is an urgent need for more and better data on the zinc status of vulnerable populations to effectively target and monitor zinc intervention programs. Plasma/serum zinc concentration is endorsed as the best available biomarker of zinc status, particularly for assessing the risk of zinc deficiency in target population groups such as preschool-aged children and women of reproductive age. But to date, national level plasma/serum zinc data for any population group exist for only 26 countries:

Percentage of pre-school children with low plasma or serum zinc concentrations ( map generated using data from WHO Micronutrient Database )

Percentage of pre-school children with low plasma or serum zinc concentrations (map generated using data from WHO Micronutrient Database)

In an effort to increase the availability and utilisation of high-quality data on zinc status at the national level in low- and middle-income countries, IZiNCG will carry out key informant interviews with survey representatives from countries where a national nutrition survey has recently been carried out. We want to better understand the hurdles and enabling factors to the inclusion of plasma/serum zinc in national surveys, and plan to talk with both those who included the assessment of plasma/serum zinc, and those who omitted it.  

Plasma/serum zinc is not the easiest of biomarkers to collect. By identifying factors that have enabled plasma/serum zinc assessment along with challenges that remain, we hope to facilitate the sharing of knowledge between countries and to promote the inclusion of plasma/serum zinc in future surveys. Findings from this project are expected early-2020.