Randomized, placebo-controlled trial of iron supplementation in infants with low hemoglobin levels fed iron-fortified formula.

In spite of the declining prevalence of iron-deficiency anemia, a large proportion of low-income infants have "low-normal" (11-11.5 g/dL) and "low" (less than 11 g/dL) hemoglobin (Hgb) values. Because most of these infants are fed iron-fortified formulas, it was of interest whether additional iron supplementation would enhance Hgb values. A cohort of 334 healthy, inner-city, minority, 6-month-old infants, fed iron-fortified formulas, with Hgb values ranging from 9 to 11.5 g/dL, participated in a double-blind, randomized, placebo-controlled trial of supplemental iron at 0, 3, and 6 mg/kg per day for 3 months. Hemoglobin values increased significantly with age, regardless of assignment to placebo or supplemental iron (means for the entire cohort: 6 months 10.9 g/dL, 8 months 11.2, 10 months 11.3, and 12 months 11.4). The proportion of "responders" (Hgb level increased greater than or equal to 1 g/dL) was 34% and did not differ significantly by placebo or iron dose. There were no significant differences in mean corpuscular volume or levels of erythrocyte porphyrins or serum ferritin between treatment groups. The implications of this clinical trial are twofold: (1) screening healthy infants fed iron-fortified formula at the age of 6 months is not justified, regardless of socioeconomic status; (2) the clinical practice of routinely treating low-income, "low-Hgb" infants with iron supplementation, without regard to dietary considerations, is unwarranted.