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 homeostasis during lactation in a population with a low zinc intake.
BACKGROUND There is a major increase in endogenous zinc excretion , specifically via the mammary gl and , in early human lactation . Whereas fractional absorption of dietary zinc has been reported to increase in early human lactation , it is not known to what extent adaptive mechanisms may maintain zinc homeostasis , especially when dietary zinc intake is relatively low . OBJECTIVE The objective of this study was to quantitate major variables of zinc homeostasis during early lactation in subjects from a population whose habitual dietary zinc intake is low . DESIGN We studied 18 free-living lactating women from a rural community of northeast China whose infants were exclusively breast-fed .  The subjects were studied at approximately 2 mo of lactation with use of stable isotopes of zinc and metabolic collection techniques .  Milk volume was measured with use of a deuterium enrichment method . RESULTS The mean ( + /-SD ) secretion of zinc in milk was 2.01 + /- 0.97 mg/d , the intake of zinc was 7.64 + /- 1.61 mg/d , and the fractional absorption of zinc was 0.53 + /- 0.09 , for a total daily zinc absorption of 4.00 + /- 0.71 mg/d . Endogenous zinc excretion in urine and feces was 0.30 + /- 0.10 and 1.66 + /- 0.97 mg/d , respectively . CONCLUSIONS Zinc balance , including zinc secreted in breast milk , was maintained at approximately 2 mo of lactation in women whose habitual diet was low in zinc . Homeostasis was achieved by high fractional absorption of zinc and intestinal conservation of endogenous fecal zinc
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 ?