Metabolic balance studies for zinc and copper in housebound elderly people and the relationship between zinc balance and leukocyte zinc concentrations.

Five-day metabolic balance studies for zinc and copper were carried out in 20 housebound elderly people with stable chronic diseases. Subjects were age 70.0-85.1 y, lived in their own homes, and ate self-selected diets. Mean daily intakes for Zn and Cu were 90 mumol and 13.4 mumol with mean negative balances of -16 and -1.1 mumol, respectively. Both balance values significantly differed from equilibrium (p less than 0.05). For Zn and Cu, respectively, mean concentrations were 11.3 and 22.1 mumol/L plasma, 103 and 19.4 mumol/L whole blood, and 98 and 8.7 pmol/10(6) leukocytes. The results for Zn and Cu balance and leukocyte concentrations were different from those obtained by us for healthy elderly people (Am J Clin Nutr 1984;40: 1096-120). A highly significant (r = 0.75, p less than 0.001) correlation was observed between zinc balance and leukocyte zinc concentrations.