Since it was first identified in an Iranian male in 1961, zinc deficiency in humans has been recognized as an important nutritional problem worldwide. It is prevalent in areas with high cereal consumption and low animal food consumption. Compared with adults, infants, children, adolescents, pregnant and lactating women have increased zinc requirements and are therefore at higher risk of zinc deficiency. Zinc deficiency during growth leads to growth failure. The epidermal, gastrointestinal, central nervous, immune, skeletal and reproductive systems are the organs most clinically affected by zinc deficiency.