Epidemiology and Etiology

What is it about?

Epidemiology - AE is more prevalent among people that have Mediterranean origin. Developing countries in Southeast Asia and Sub-Saharan Africa are mostly affected by zinc deficiency since there is a higher prevalence of malnutrition in these regions. Infants and children are the ones that are mostly affected by malnutrition and subsequent zinc deficiency. Zinc is a very important micronutrient as it’s involved in early growth and development. Zinc deficiency among children and infants can have long lasting effects such as growth retardation and deformity. Etiology - There are two main hypotheses regarding the cause of AE. One hypothesis focuses on bioavailability of zinc and the other one focuses on transport of zinc to bloodstream (absorption) (2).

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Why is it important?

Epidemiology - Infants usually develop AE symptoms after weaning because breast milk has more bioavailable zinc compared to that of bovine milk or milk formula. In US, the main factor that causes zinc deficiency in infants is milk formula with low zinc content. This is definitely concerning as infants require higher levels of zinc intake for rapid development and growth compared to adults. Among adults, high alcohol consumption, metabolic disorders, aging, and lactation are the primary factors causing zinc deficiency (2). Etiology - Consumption of high dosage of iron in solution apart from meals can also lower the absorption of zinc. Cadmium in toxic levels can lower zinc consumptions. Chelators (e.g. histidine) and low molecular weight ligands such as zinc binding ligands can enhance absorption of zinc but excess amount may cause adverse effects (3).