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%.
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.