2.7.2 Zinc (Zn)

FUNCTION Zinc is necessary for normal growth, sexual development, and reproduction. A deficiency leads to loss of appetite, failure to grow and to develop sexually, slow wound healing, decreased sense of taste, and changes in skin texture. PROBLEMS IN DRYLANDS Zinc deficiency is found in the Near East, especially Iran and Egypt. The availability of dietary zinc is reduced by binding with phytates and fiber,⁵⁰ which may be a problem with some dryland diets. REQUIREMENTS The RDA for the United States of 15 mg/day for men and 12 mg/day for women⁵¹ assumes regular consumption of animal products. Absorption of zinc in persons on largely vegetarian diets may be limited, due in part to phytates and fiber in the diet, and so the RDA may be higher. SOURCES Most seeds are high in zinc; for example, pumpkin seeds have 7 mg/100 gm. Zinc is also found in DGLVs, pulses, eggs, milk, seafood, and meat. The zinc content of plants (and of animal products formed from them) depends upon the zinc content of the soil.