Evoked potentials provide noninvasive measures of nerve transmission and CNS functioning. Auditory brainstem responses (ABR) and visual evoked potentials (VEP) show dramatic changes in infancy, largely as a result of progressive myelination. Because iron is required for normal myelination, pathway transmission in these sensory systems might be affected by early iron deficiency. We previously reported evidence to that effect: infants with iron-deficiency anemia (IDA) had slower transmission through the auditory brainstem pathway, uncorrected by iron therapy. To determine long-term effects, ABR and/or VEP of healthy Chilean children who were treated for IDA or were nonanemic in infancy were compared at approximately 4 y of age. Absolute latencies for all ABR waves and interpeak latencies (except I-III interval) were significantly longer in former IDA children. Longer latency was also observed for the P100 wave on VEP. The magnitude of differences was large-about 1 SD. These findings, with differences in latencies but not amplitudes, further support the hypothesis that IDA in infancy alters myelination and provide evidence that effects on transmission through the auditory and visual systems can be long lasting. Subtle changes in sensory pathway transmission might be an underlying mechanism for the derailment of other developmental aspects in early IDA. Neurophysiologic methodologies are noninvasive approaches that can provide information about the functional integration of the CNS. For example, dramatic decreases in latencies in auditory and visual evoked potentials in infancy are often used to index the overall intactness and maturation of the CNS. Progressively shorter latencies until adult levels are achieved are thought to reflect the increasing speed of transmission through sensory pathways, resulting in large part from increased myelination of the auditory and optic nerves and at the intracerebral level (1-5).ABR represent the progressive activation of different levels of the auditory pathway: wave I is generated peripherally in the auditory nerve, wave III reflects the firing of axons exiting the cochlear nuclear complex, and wave V reflects an action potential generated by axons from the lateral lemniscus (6, 7). We recently reported the use of ABR to determine the effects of early IDA on the functional development of the auditory system (8). Six-month-old Chilean infants with IDA tended to show longer latencies than controls, indicating slower transmission through the brainstem portion of the auditory pathway. Differences became pronounced at 12 and 18 mo, despite iron therapy. Because iron is required for the functioning of several neurotransmission systems, myelination, and neuronal metabolic activity, different processes may relate to these lasting ABR abnormalities. However, the findings of differences in latency but not amplitude and more effects on the central (versus peripheral) portion of the auditory pathway appeared to be strong support for the hypothesis that impaired myelination was the explana...

In a longitudinal study from age 3 to 15 mo, 276 term, healthy, spontaneously weaned infants received a full-fat acidified milk fortified with 15 mg of elemental Fe as ferrous sulfate and 100 mg of ascorbic acid/100 g of powder and 278 control infants received milk without additives. At ages 9 and 15 mo significant differences were encountered in all measures of Fe nutriture in favor of the fortified group (p less than 0.001). Anemia (Hg less than 110 g/L) was present in 25.7% of unfortified infants compared with only 2.5% in those fortified at age 15 mo. Saturation of transferrin less than 9% was present in 33.8% and serum ferritin less than 10 micrograms/L in 39.1% of the nonfortified infants. The figures for the fortified group were 7 and 8.5% respectively. The efficiency of the fortified acidified milk in eradicating Fe deficiency in the infants while discouraging use by other family members make this milk a useful targeted product in programs of supplementary food distribution in the underdeveloped world.

ABSTRACT

We describe a quantitative method for determination of iron in stool to monitor consumption of iron-fortified milk in infants. The method is simple, fast, and inexpensive. Stool samples from infants consuming fortified milk or nonfortified milk were ashed, and ashes were diluted in hydrochloric acid and reacted with bathophenantroline disulphonate. Mean iron excretion per subject was obtained. Anemia was present in 25.7% of infants in the nonfortified group (upper level of 95% confidence limit for mean iron excretion was 14.9 mg iron/100 g stool) and in 22.2% of infants from the noncompliant fortified group (mean excretion less than 15 mg iron/100 g stool). In contrast, only 0.8% of infants who had properly consumed the fortified milk had anemia. We conclude that this method for determination of stool iron should be considered for estimating compliance in evaluation of results of field trials of iron-fortified products in infants.

Background. Iron deficiency continues to be a common problem among infants throughout the world. Iron-fortified formula is effective in preventing iron deficiency but the benefit of iron-fortified cereal is controversial. Methods. We compared iron-fortified rice cereal to unfortified rice cereal in infants who were exclusively breast-fed for more than 4 months and to iron-fortified formula in infants who were weaned to formula before 4 months of age. The design was double blind in respect to the presence or absence of fortification iron in the cereal or formula and included 515 infants who were followed on the protocol from 4 to 15 months of age. Rice cereal was fortified with 55 mg of electrolytic iron per 100 g of dry cereal and infant formula with 12 mg of ferrous sulfate per 100 g of dry powder, levels approximating those in use in the United States. Measures of iron status were obtained at 8, 12, and 15 months. Infants with hemoglobin levels of <105 g/L were excluded from the study and treated. Results. Consumption of cereal reached plateaus at means of about 30 g/d after 6 months of age in the formula-fed groups and 26 g/d after 8 months in the breast-fed groups; these amounts are higher than the 19-g/d mean intake by the 73% of infants who consume such cereal in the United States. Among infants weaned to formula before 4 months, the cumulative percentages of infants excluded for anemia by 15 months were 8%, 24%, and 4%, respectively, in the fortified cereal, unfortified cereal and formula, and fortified formula groups (P < .01 unfortified vs either fortified group; the difference between the two fortified groups was not significant). In infants breast-fed for more than 4 months, the corresponding values were 13% and 27%, respectively, in the fortified and unfortified cereal groups (P < .05). Mean hemoglobin level and other iron status measures were in accord with these findings. Conclusion. Iron-fortified infant rice cereal can contribute substantially to preventing iron deficiency anemia.