Calcium levels in maternal milk: relationships with calcium intake during the third trimester of pregnancy.
The aim of the present study was to investigate the relationship of Ca intake and serum Ca levels during the third trimester of pregnancy with levels of the same mineral in transition milk (days 13-14 of lactation) and mature milk (day 40 of lactation). The study subjects were a group of fifty-seven healthy, lactating mothers aged between 18 and 35 years (mean 27 (SD 3.7) years) whose pregnancies and labour were attended by the Department of Obstetrics and Gynaecology of Cuenca INSALUD Hospital, Spain. Ca intake during the third trimester was determined by recording the consumption of foods over a 5 d period and by registering Ca provided by dietary supplements. The same method was used to investigate the intake of protein, vitamin D, fibre and Fe, nutrients that could affect the use of dietary Ca. Ca levels in maternal serum during this stage of pregnancy, during lactation and in transition and mature milk samples, were determined using 2-cresolphthalein complexone. During pregnancy 70.2% of subjects showed Ca intakes below 1100 mg/d (75th percentile). The consumption of Ca supplements was very small and hardly modified the mean quantity supplied by the diet. Subjects with an intake < 1100 mg/d showed no fall in Ca levels in serum, either during pregnancy or lactation, nor were decreased levels found in transition milk. However, these subjects showed lower Ca levels in mature milk (5.95 (SD 1.56) mmol/l) than did subjects with greater Ca intakes (6.82 (SD 1.31) mmol/l). This may suggest that breast-fed babies of mothers with lower Ca intakes during pregnancy also receive less Ca.
Ortega
R M
RM
Departamento de Nutrición, Facultad de Farmacia, Universidad Complutense, Madrid, Spain. rortega@eucmax.sim.ucm.es
Martínez
R M
RM
Quintas
M E
ME
López-Sobaler
A M
AM
Andrés
P
P
D000293:Adolescent; D000328:Adult; D002118:Calcium / Q000032:analysis* / Q000097:blood; D002136:Calcium, Dietary / Q000008:administration & dosage*; D004043:Dietary Fiber / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D005260:Female; D006801:Humans; D019266:Iron, Dietary / Q000008:administration & dosage; D008895:Milk, Human / Q000737:chemistry*; D011247:Pregnancy / Q000378:metabolism*; D011263:Pregnancy Trimester, Third; D014807:Vitamin D / Q000008:administration & dosage
D002136:Calcium, Dietary; D004043:Dietary Fiber; D004044:Dietary Proteins; D019266:Iron, Dietary; D014807:Vitamin D; D002118:Calcium