Blood and urinary zinc changes after a glucose challenge in early and late pregnancies

This study was undertaken to investigate the effect of pregnancy and glucose loading on zinc metabolism. In a completely random design with repeated measures, 18 non-pregnant women, 16 early-pregnant women (13–17 wk), and 16 late-pregnant women (28–34 wk) had blood collected at 0, 30, 60, 120, and 180 min after ingesting 100 g glucose to evaluate changes in variables of Zn nutriture. Fasting plasma Zn concentrations decreased significantly as pregnancy progressed. Late-pregnant women had significantly higher erythrocyte Zn levels and greater 24-h urinary Zn and glucose excretions. Erythrocyte Zn responses to glucose loading were unaffected by gestational age. Plasma Zn after a glucose load in nonpregnant women exhibited a curvilinear response whereas pregnant women showed no change. This lack of response by pregnant women may be related to their lower plasma Zn concentrations. Plasma Zn in pregnant women may not be as readily available to assist in glucose utilization.