Abstract
Studies on rickets of prematurity have focussed on the calcium, phosphorus and vitamin D requirements of infants, but skeletal development may be stressed if magnesium is deficient. The present study examines the effects of increasing calcium and phosphorus on magnesium retention. Five groups of very low birthweight infants were fed milk with magnesium content 5 mg/100 ml. Calcium and phosphorus were supplemented to the following concentrations (Ca:P mg/100 ml); Group A 44:33, Group B 84:33, Group C 125:33, Croup D 125:50 and Group E 125:64. Three-day balance studies were performed starting at 10, 20, 30 and 40 days. Increasing both calcium and phosphorus contents decreased magnesium retention to lower than in utero accretion rates. Doubling magnesium content of milk to 10 mg/100 ml did not prevent negative magnesium balance in very preterm infants at 10 days, although magnesium retention doubled in older (20 days) or more mature (32-34 weeks gestation) infants. We conclude that increasing calcium and phosphorus content of milks to prevent rickets of prematurity could produce a magnesium deficiency in very low birthweight infants, with possible compromise of bone formation.
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Laing, I., Giles, M., Elton, R. et al. MAGNESIUM METABOLISM IN PRETERM INFANTS: THE EFFECT OF CALCIUM AND PHOSPHORUS. Pediatr Res 26, 507 (1989). https://doi.org/10.1203/00006450-198911000-00049
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DOI: https://doi.org/10.1203/00006450-198911000-00049