Zinc absorption and kinetics during pregnancy and lactation in Brazilian women
American Journal of Clinical Nutrition
Adjustments in zinc absorption and endogenous excretion maintain zinc homeostasis in nonpregnant adults fed lowzinc diets. The effects on zinc homeostasis of a low zinc intake during pregnancy and lactation have not been described in a longitudinal study. Objective: We examined longitudinal changes in fractional zinc absorption (FZA) and zinc kinetics in 10 healthy Brazilian women who habitually consumed a marginal zinc diet (Ȃ9 mg Zn/d). Design: Zinc status was measured at 10 -12 (early
... cy; EP) and 34 -36 (late pregnancy; LP) wk of pregnancy and at 7-8 wk after delivery (early lactation; EL). Zinc kinetics and FZA were studied by using stable isotopic tracers. Results: Zinc intake averaged 9 Ȁ 3 mg/d throughout the study. FZA increased from 29 Ȁ 6% at EP to 43 Ȁ 10% at LP and to 39 Ȁ 13% at EL (P 0.05). FZA was inversely related to plasma zinc at EL (r ҃ Ҁ0.73, P ҃ 0.02) and LP (r ҃ Ҁ0.72, P ҃ 0.07). Plasma zinc mass was 23% greater at LP than at EP or EL (P 0.05). The amount of zinc (mg/d) that fluxed between plasma and the most-rapidlyturning-over extravascular pool was 53% greater at LP than at EP or EL (P 0.05). The zinc flux between plasma and the less-rapidlyturning-over zinc pool at EL was 27% greater than that at EP or LP, but this difference was not significant. Conclusions: FZA increased significantly in women with marginal zinc intakes during pregnancy and lactation; the increase was higher in women with low plasma zinc. Plasma zinc was distributed into a different exchangeable pool at LP than at EL. Am J Clin Nutr 2005;82:118 -24.