Adequate zinc nutrition is essential for human health because of zinc’s critical structural and functional roles in multiple enzyme systems that are involved in gene expression, cell division and growth, and immunologic and reproductive functions. Zinc deficiency is an important driver of undernutrition in children under 5 years of age and is associated with growth stunting, lower respiratory infections and diarrhea. It is known that even a mild deficiency of zinc in humans affects clinical, biochemical, and immunological functions adversely. During the past 50 years, it has become apparent that deficiency of zinc in humans is prevalent. The major factor contributing to zinc deficiency is high phytate-containing cereal protein intake. Phytates—which are present in whole-grain breads, cereals, legumes, and other foods—bind zinc and inhibit its absorption. Symptoms of zinc deficiency can include growth retardation, loss of appetite, and impaired immune function. In more severe cases, zinc deficiency causes hair loss, diarrhea, delayed sexual maturation, impotence, hypogonadism in males, and eye and skin lesions. Oysters, red meat, and poultry are excellent sources of zinc. Baked beans, chickpeas, and nuts (such as cashews and almonds) also contain zinc. Supplementation may also be considered in cases of deficiency.