The reproducibility of the plasma response to a physiological dose of zinc in healthy subjects. Implications for study design.
Zinc absorption may be estimated by measuring the area under the plasma zinc curve following the ingestion of a zinc supplement. The aim of this study is to determine the reproducibility of such a response when a small dose of zinc is administered to healthy volunteers. Five female subjects were asked to consume 4.5 mg elemental zinc, and blood samples were obtained at 30 min intervals for 5 h. The experiment was repeated in the same volunteers 12-16 d later. The area under the plasma zinc curve was 30% lower after the second zinc tolerance test compared with the first (11.0 vs 15.8 mumol/l h). This difference could not be explained by differences in the fasting plasma zinc levels (12.9 mumol/L Experiment one, 15.1 mumol/L Experiment 2) nor was it related to technical or clinical parameters. The area under the curve after 5 h was strongly correlated with the response after 4 h. Hence we conclude that a small dose of zinc can be used to determine zinc absorption and a shorter experimental period may be used. However, trials must be designed to take into account the sequence variability in the response.
Samman
S
S
Department of Biochemistry, University of Sydney, NSW, Australia.
van het Hof
K
K
Snitch
P
P
D000042:Absorption; D000284:Administration, Oral; D005260:Female; D006801:Humans; D012044:Regression Analysis; D015203:Reproducibility of Results; D015032:Zinc / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology
D015032:Zinc