Calcium intake in the first five days of life in the low birthweight infant. Effects of calcium supplements.

Sixteen low birthweight infants were allocated to two groups. Both groups 1 and 2 received a formula with Ca/PO4 ratio of 1.21. Group 2 infants received a supplement of 800 mg/kg per day of Ca and Mg lactate, and the daily Ca, Mg, and PO4 levels were measured. Calcium intakes (mg/kg per day) were, comparing groups 2 and 1: 82 v. 33 on the 1st day; 133 v 45 on 2nd; 170 v. 56 on 3rd; 224 v 72 on 4th; 263 v. 88 on 5th. Magnesium intake (mg/kg per day) was 4.9 v. 3.8 on the 1st day; 8.3 v. 5.3 on 2nd; 9.8 v. 6.5 on 3rd; 15.5 v. 8.3 on 4th; 16.0 v. 10.0 on 5th. Phosphate intake was similar in both groups. Mineral content of vomits and regurgitations showed more Ca than P, with a ratio of 1:68. Comparing the two groups, in the supplemented infants, serum Ca rose from the 3rd day by an amount which was related to Ca intake: serum Mg was lower from the 4th day and was negatively correlated with Ca intake.