[Mineral metabolism of calcium, magnesium and phosphorus in the normal newborn infant].

The mineral metabolism of calcium, magnesium and phosphorus in 20 newborns and infants was studied. All children were born from term deliveries and none presented clinic, biochemistry signs or radiological evidences of bone mineral metabolism disturbances. In this way, metabolic blance technics were applied. Net absorption of calcium, magnesium and phosphorus were: 54,9 +/- 18,8; 8,7 +/- 4,8 and 64,6 +/- 14,2 mg/kg/day respectively. The retentions of the three elements were: 54,4 +/- 20,6; 7,4 +/- 4,5 and 43,2 +/- 13,6 mg/kg/day. A significative lineal correlation between plasmatic levels of 250Hd and 24,25 (OH)2D with calcium retention was found. The correlation of intestinal calcium apsorption was positive and significative only with 250HD levels. It wasn't found signification between the vitamin D metabolites with the magnesium and phosphorus balance. In other way, it was found a relation between the dietary intake of this two elements with absorption and retention of both of them.