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"I thought that behavior
and development would be better with the 12 mg formula," said Lozoff, also
professor of pediatrics in the U-M Department of Pediatrics and Communicable
Diseases at the Medical School and C.S. Mott Children's Hospital
The U-M study of 494 Chilean children showed that those who received iron
fortified formula in infancy at the 12 mg used in the U.S. lagged behind those
who received low-iron formula in cognitive and visual-motor development by age
10 years. Lozoff stressed that most children who received the 12 mg formula did
not show lower scores. But the 5 percent of the sample with the highest
hemoglobin levels at 6 months showed the poorest outcome. Your body needs iron
to make hemoglobin, a substance in red blood cells that enables them to carry
oxygen. High hemoglobin generally indicates sufficient iron.
Adversely affected children scored 11 points lower in IQ and 12 points lower in
visual-motor integration, on average; the average overall score on both tests
was 100. A similar pattern was observed for spatial memory and other
visual-motor measures.
Lozoff noted that not many infants in Chile had high hemoglobin levels at the
time since there was no iron-fortification program for infants and that more
than 5 percent of U.S. infants might have high hemoglobin levels in early
infancy.
In this randomized study, healthy infants without iron-deficiency anemia were
given formula with either 12 mg or 2.3 mg iron from 6 to 12 months and followed
to 10 years. The next step is to test the participants again at age 16, Lozoff
said, who says that no such study has been conducted in the United States or
elsewhere.
Iron deficiency occurs because babies grow so quickly they often "grow
out" of the amount of iron they are born with. Breast milk is thought to
contain the iron a baby needs for 4-6 months, Lozoff said. Other important
sources of iron for infants include iron-fortified infant formulas and cereals,
iron drops and meat.
Infants are typically not tested for hemoglobin or iron levels before 9-12
months. It would be premature to recommend earlier testing or to avoid
supplemental iron based on the study's results, Lozoff said. She expects parents
to be concerned, but stressed that results must be reproduced in other studies.
"At this point there's no basis for changing practice, but it's really
important that we have continued research on this issue," she said.
The paper, "Poorer developmental outcome at 10 years with 12 mg/L
iron-fortified formula in infancy," was expected to be presented May 5 at
the Pediatric Academic Societies annual meeting in Honolulu. Co-authors on the
study include: Marcela Castillo, Institute of Nutrition and Food Technology,
University of Chile, Santiago, Chile, and Julia B. Smith, Educational
Leadership, Oakland University, Michigan.
The infancy and follow-up studies have been supported by the National Institute
of Child Health and Human Development at NIH.
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