Copper and zinc utilization in elderly adults.

Elderly adults were provided with 2.33 mg of copper and either 7.80 or 23.26 mg of zinc daily during a 30-day metabolic study. Excretions of both minerals were measured throughout the study. The subjects were able to maintain apparent positive balance for copper, but were in negative balance for zinc on both levels off intake. Copper retention was significantly reduced by intake of the higher amount of zinc. These results support other reports indicating antagonism between the two nutrients. The hair content of zinc and copper was higher in females than in males and was in the ranges indicative of long-term adequate intakes. Recumbent length was significantly greater than standing height and should be investigated further as a more accurate measure of body height in the elderly.