We hypothesize , therefore , that zinc homeostatic adjustments during pregnancy and lactation improve zinc utilization sufficiently to provide the increased zinc needs in these stages and , therefore , mitigate immediate detrimental effects due to a low zinc intake .
Zinc plays critical roles during embryogenesis , fetal growth , and milk secretion , which increase the zinc need for pregnancy and lactation .
Increased needs can be met by increasing the dietary zinc intake , along with making homeostatic adjustments in zinc utilization .
Potential homeostatic adjustments include changes in circulating zinc , increased zinc absorption , decreased zinc losses , and changes in whole body zinc kinetics .
Although severe zinc deficiency during pregnancy has devastating effects , systematic review s and meta- analysis of the effect of maternal zinc supplementation on pregnancy outcomes have consistently shown a limited benefit .
The specific questions addressed are the following : How is zinc utilization altered during pregnancy and lactation ?
Are those homeostatic adjustments influenced by maternal zinc status , dietary zinc , or zinc supplementation ?
Zinc absorption and kinetics during pregnancy and lactation in Brazilian women.
BACKGROUND Adjustments in zinc absorption and endogenous excretion maintain zinc homeostasis in nonpregnant adults fed low-zinc 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 ( approximately 9 mg Zn/d ) . DESIGN  Zinc status was measured at 10 - 12 ( early pregnancy ; 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 + /- 3 mg/d throughout the study . FZA increased from 29 + /- 6 % at EP to 43 + /- 10 % at LP and to 39 + /- 13 % at EL ( P < 0.05 ) . FZA was inversely related to plasma zinc at EL ( r = -0.73 , P = 0.02 ) and LP ( r = -0.72 , 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-rapidly-turning-over extravascular pool was 53 % greater at LP than at EP or EL ( P < 0.05 ) . The zinc flux between plasma and the less-rapidly-turning-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
We hypothesize , therefore , that zinc homeostatic adjustments during pregnancy and lactation improve zinc utilization sufficiently to provide the increased zinc needs in these stages and , therefore , mitigate immediate detrimental effects due to a low zinc intake .
Zinc plays critical roles during embryogenesis , fetal growth , and milk secretion , which increase the zinc need for pregnancy and lactation .
Increased needs can be met by increasing the dietary zinc intake , along with making homeostatic adjustments in zinc utilization .
Potential homeostatic adjustments include changes in circulating zinc , increased zinc absorption , decreased zinc losses , and changes in whole body zinc kinetics .
Although severe zinc deficiency during pregnancy has devastating effects , systematic review s and meta- analysis of the effect of maternal zinc supplementation on pregnancy outcomes have consistently shown a limited benefit .
The specific questions addressed are the following : How is zinc utilization altered during pregnancy and lactation ?
Are those homeostatic adjustments influenced by maternal zinc status , dietary zinc , or zinc supplementation ?