Evaluation of Two Iron-Fortified, Milk-Based Formulas During Infancy

Abstract

Objective. Compare milk-based, ironfortified formulas containing 7.4 and 12.7 mg/L iron and breast-feeding during the first year of life. Design. Partially randomized, double-blind trial: non-breast-fed infants randomly assigned to receive one of two coded formulas, identical except for iron content; infants discontinuing breast-feeding between 1 and 8 weeks of age randomly assigned to a formula late-start group. Setting. Five general community pediatric practices in Missouri, Indiana, Illinois, and Pennsylvania. Participants. Sample of 347 healthy, term infants, enrolled within 1 week after birth; 172 included in statistical analyses. Outcome measures. Length, weight, and indicators of formula intolerance recorded at clinic visits; formula consumption, bowel movements, stool consistency, and other tolerance indicators recorded by parents on daily and weekly report forms; hemoglobin, hematocrit, and serum ferritin, iron, zinc, and copper measured at 6 and 12 months. Results. No significant differences between formula-fed groups in growth, attrition, formula consumption, bowel movements, hematocrit, hemoglobin level, and serum iron, zinc, and copper levels (P > .05); first 6-month weight and length changes of the breast-fed group significantly less than in both formula-fed groups (P < .008); serum ferritin level of the formula-fed, high-iron group significantly higher than that of the low-iron and breast-fed groups (P < .008), although all groups' values were normal; no apparent differences between formula groups in formula tolerance and stool characteristics but data were not analyzed statistically. Conclusions. Milk-based formulas containing either 7.4 or 12.7 mg/L iron support normal growth and iron status of healthy, term, normally fed infants during the first year and both are well tolerated and accepted.