Calcium and phosphorus supplementation of iron-fortified infant formula: no effect on iron status of healthy full-term infants.

One objective of this clinical trial was to determine whether calcium and phosphorus supplementation of infant formula affects the iron status of healthy full-term infants. One hundred three infants were randomly assigned to receive iron-fortified, cow milk-based infant formula (465 mg Ca and 317 mg P/L) or the same formula with added calcium glycerophosphate (1800 mg Ca and 1390 mg P/L) for 9 mo. Reported calcium intake for supplemented infants was about four times that of control infants, ranging from a mean of 1741 mg/d at baseline to 1563 mg/d at 9 mo. There was no difference by treatment group in mean or median change from baseline of serum ferritin, total-iron-binding capacity, erythrocyte protoporphyrin, or hematocrit at 4 and 9 mo after enrollment. Incidence of iron deficiency was similar for both groups and no infant developed iron deficiency anemia during the trial. This study indicates that the well-documented inhibitory effect of calcium and phosphorus on iron absorption is not clinically important in infants fed iron-fortified infant formula.