Prevention of iron-deficiency anemia: comparison of high- and low-iron formulas in term healthy infants after six months of life.

OBJECTIVES: For bottle-fed babies or nursing infants who receive milk supplements, the American Academy of Pediatrics recommends the use of iron-fortified infant formula. Because these recommendations have not been universally adopted, the hematologic effects of currently available low-iron formulas need to be determined.

STUDY DESIGN: Healthy Chilean 6-month-old infants (without iron-deficiency anemia, born at term weighing > or 3.0 kg) who were totally or partially weaned from the breast were randomly allocated in a double-blind fashion to receive high-iron (n = 430) or low-iron formula (n = 405), containing an average of 12.7 mg/L or 2.3 mg/L, respectively, of elemental iron as ferrous sulfate. Iron status was determined at 12 months.

RESULTS: The prevalence of iron-deficiency anemia was not different in the high- and low-iron groups (2.8% versus 3.8%, p = 0.35). Nevertheless, infants receiving high-iron formula had somewhat higher levels of hemoglobin and serum ferritin, greater mean cell volumes, and lower erythrocyte protoporphyrin levels (p < 0.005).

CONCLUSIONS: Although high-iron formulas are more efficacious in improving iron status, currently available low-iron formulas may prevent iron-deficiency anemia in selected healthy, term infant populations with otherwise poor sources of dietary iron after 6 months of life. Formulas with relatively small amounts of iron appear to prevent iron-deficiency anemia. We speculate that the optimal level of iron fortification likely lies somewhere between the current levels in high- and low-iron formulas.