A review of the biochemical roles, toxicity and interactions of zinc, copper and iron: I. Zinc.

Zinc is essential for biological functions of all living matter. Zinc is necessary for growth, appetite, testicular maturation, skin integrity, mental activity, wound healing and immunocompetence. Zinc is required for the metabolic activities of over 70 metalloenzymes. The intestinal competition of zinc with copper, iron, lead, calcium and cadmium may accentuate nutritional deficiencies or toxicities from these environmental metals. A unifying hypothesis is not yet established for the effects or imbalances among these elements. These interactions will be of substantial practical importance in estimating dietary recommendations, in validating prophylactic measures, and in the assessment of situations in which human and animal health may be at risk.