A two-compartment model for zinc in humans

The oral absorption of zinc, from a test meal of minced beef, mashed potato es and peas, have been measured in 19 healthy adults using the radiotracer Zn-65. The oral absorption, expressed as a percentage of the administered d ose, was 20 +/- 5% (mean +/- SD) in good agreement with previous results. I n a subset of 9 subjects, tracer retention in whole body and whole blood wa s followed out to one year. The data were fitted to a simple two compartmen t model yielding total body zinc (TBZn), the zinc content in each of the 2 compartments and zinc turnover. The TBZn values ranged from 15.5 to 35.9 mm ol while zinc turnover ranged from 0.043 to 0.073 mmol/d in keeping with re sults reported for significantly more complicated compartmental models appl ied to more comprehensive Zn-65 tracer data sets. Additionally, TBZn correl ated well with total body potassium, a measure of lean body mass, measured by whole body counting of the naturally-occurring potassium radioisotope, 4 0K. The zinc content of the mon rapidly running over compartment ranged fro m 3.2 to 5.6 mmol in reasonable agreement with exchangeable zinc pool estim ations reported for short term studies using stable zinc isotopes. Therefor e, the simple dataset and model employed in the present study yielded infor mation on the short- and long-term behaviour of zinc compatible with both m ore complex radiotracer studies and analytically more demanding stable isot ope studies.