Zinc

a chemical element, atomic number 30, atomic weight 65.37, symbol Zn. (See Appendix 6.) It is a trace element in the diet, a component of several enzymes, including DNA and RNA polymerases and carbonic anhydrase. It is abundant in red meat, shellfish, liver, peas, lentils, beans, and rice. A well-balanced diet assures adequate intake of zinc. Those who may suffer from zinc deficiency include persons on a strictly vegetarian diet and those who are on a high-fiber diet. In the latter case, the zinc is bound to the fiber and is eliminated in the feces without having been absorbed through the intestinal wall. Poor absorption of zinc also can occur in persons with chronic and severe bowel disease. The recommended daily intake is 12–15 mg for an adult. A severe deficiency of zinc can retard growth in children, cause a low sperm count in adult males, and retard wound healing. Signs of a deficiency include anorexia and a diminished sense of taste. An excessive intake of zinc (usually in those who work with the metal or breathe its fumes) can either cause pneumoconiosis or interfere with the body's use of copper and other trace elements, producing diarrhea, nausea, vomiting, and other signs of intestinal irritation.