Zinc levels of hospitalized elderly

Zinc status was evaluated in 99 consecutive elderly patients admitted to a geriatric assessment unit. The assessment of zinc status was based on measurement of plasma, erythrocyte, and urinary zinc levels by atomic absorption spectrophotometry; serum lactic dehydrogenase and alkaline phosphatase by standard laboratory methods; and dietary intake by the food frequency questionnaire method. Mean (+/- standard deviation) plasma zinc concentration was 72 +/- 16 micrograms/100 ml (N = 91). Although 67% of the group had plasma zinc levels in the deficient range, only three patients had values below the normal range for erythrocyte zinc and none fell below the reference range for urinary zinc per 24 hours (N = 15) or the urinary zinc:creatinine ratio. Mean values for the other parameters of zinc status were 1.27 +/- 0.26 micrograms/10(9) RBC for erythrocyte zinc, 285 +/- 217 micrograms/24 hours for urinary zinc, and 588 +/- 309 micrograms/gm for the urinary zinc:creatinine ratio. Serum alkaline phosphatase and lactic dehydrogenase were not specific indicators of zinc status. Forty-six percent had adequate and 54% inadequate dietary intakes (N = 46). Twenty percent were receiving an inadequate intake of meat products, suggesting that the majority (80%) were ingesting an adequate supply of zinc-rich foods. Zinc status appeared to be adequate in this population.