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).


METHODS
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.
Donangelo
Carmen M
CM
Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Zapata
Carmiña L Vargas
CL
Woodhouse
Leslie R
LR
Shames
David M
DM
Mukherjea
Ratna
R
King
Janet C
JC
D000328:Adult; D001938:Brazil; D004032:Diet; D005260:Female; D006706:Homeostasis; D006801:Humans; D007408:Intestinal Absorption; D007774:Lactation / Q000378:metabolism*; D008137:Longitudinal Studies; D011203:Poverty; D011247:Pregnancy / Q000378:metabolism*; D015032:Zinc / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
D015032:Zinc