Calcium supplementation during lactation blunts erythrocyte lead levels and delta-aminolevulinic acid dehydratase zinc-reactivation in women non-exposed to lead and with marginal calcium intakes.
The purpose of this study was to evaluate the effect of calcium supplementation during lactation on changes in blood lead indices from late pregnancy to early lactation in women with low calcium intakes and low lead-exposure. Forty-seven women, non-occupationally exposed to lead and with habitually low calcium intake ( approximately 600 mg/d), participated in the study from 29 to 38 weeks of pregnancy to 7-8 weeks post-partum, non-supplemented (n=25) and supplemented (n=22) with calcium (500 mg/d) during 6 weeks after delivery. Erythrocyte lead (PbRBC) and in vitro reactivation with zinc of blood delta-aminolevulinic acid dehydratase (Zn-delta-ALAD% reactivation) were used as lead indices. In the non-supplemented group, PbRBC and Zn-delta-ALAD% reactivation increased significantly (P<0.001) from pregnancy (0.202+/-0.049 microg Pb/g protein and 18.3+/-6.0%) to lactation (0.272+/-0.070 microg Pb/g protein and 22.7+/-6.2%). No significant changes of these indices were observed in the calcium-supplemented group from pregnancy (0.203+/-0.080 microg Pb/g protein and 15.8+/-4.5%) to lactation (0.214+/-0.066 microg Pb/g protein and 16.3+/-4.1%). PbRBC levels and Zn-delta-ALAD% reactivation at lactation were lower (P<0.05) and hematocrit levels were higher (P<0.05) in the calcium-supplemented compared to the non-supplemented women. Calcium supplementation during lactation appears to blunt the lactation-induced increase in maternal blood lead and its inhibitory effect on delta-ALAD and possibly on maternal erythropoiesis.
Pires
Jandyra B
JB
Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, CT, Bloco A, 528, 21949-900 Rio de Janeiro, Brazil.
Miekeley
Norbert
N
Donangelo
Carmen M
CM
D000293:Adolescent; D000328:Adult; D001938:Brazil; D002118:Calcium / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism; D019587:Dietary Supplements; D004789:Enzyme Activation / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006801:Humans; D007774:Lactation / Q000097:blood*; D007854:Lead / Q000097:blood*; D000623:Porphobilinogen Synthase / Q000097:blood*; D011247:Pregnancy; D013383:Suburban Population; D015032:Zinc / Q000097:blood / Q000494:pharmacology*
D007854:Lead; D000623:Porphobilinogen Synthase; D015032:Zinc; D002118:Calcium