[Calcium and phosphorus balance in rural lactating women in Mexico].
OBJECTIVE
To compare the balance of calcium (Ca) and phosphorus (P) between lactation and weaning, and to determine the Ca and P milk production in Mexican rural lactating women.


METHODS
Thirty-six women aged 18-36 y, weight 49 +/- 3 kg and height 148 +/- 2 cm, were divided in six groups: four groups of lactation (1st, 3rd, 6th and 12th month) one post-weaning group and one of non pregnant non lactating women. The balance studies were performed collecting duplicate diets, 24 h urine for 3 days, 72 h feces and 24 h milk samples for 2 days. The Ca content was determined by atomic absorption spectrophotometry and P by the molybdate method.


CONCLUSIONS
Ca content in milk was higher in the 3rd month of lactation. The Ca balances were negative in all lactation groups (789 +/- 165 mg/d). Ca urinary excretion was lower in the lactating group (p < 0.05) suggesting a regulatory mechanism to conserve Ca during lactation. No differences were observed in the P content in milk and positive balances of P were observed in the non lactating and the post-weaning groups, whereas they were negative in the lactation groups (115 to 475 mg/d). High fecal Ca and P excretion (approximately 1300 mg/d) was observed, which contributed to the negative condition of the balance during lactation. The production of Ca and P in the milk of these rural women was similar to the one seen in rural and urban groups in Africa, Asia, Europe and the U.S.
DeSantiago
S
S
Departamento de Fisiología de la Nutrición Salvador Zubirán, Instituto Nacional de la Nutrición, México D.F.
Halhalí
A
A
Perea
F
F
Alonso
L
L
Jasso
F
F
Isoard
F
F
D000328:Adult; D002118:Calcium / Q000378:metabolism*; D005260:Female; D006801:Humans; D007774:Lactation / Q000378:metabolism*; D008800:Mexico; D008895:Milk, Human / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D012016:Reference Values; D012423:Rural Health
D010758:Phosphorus; D002118:Calcium
Balance de calcio y fósforo en mujeres lactantes rurales de México.