Supplementation With Iron Syrup or Iron-Containing Multiple Micronutrient Powders Alters Resting Brain Activity in Bangladeshi Children.

BACKGROUND: Anemia and iron deficiency have been associated with poor child cognitive development. A key rationale for the prevention of anemia using supplementation with iron has been the benefits to neurodevelopment. However, little causal evidence exists for these gains. OBJECTIVES: We aimed to examine effects of supplementation with iron or multiple micronutrient powders (MNPs) on brain activity measures using resting electroencephalography (EEG). METHODS: Children included in this neurocognitive substudy were randomly selected from the Benefits and Risks of Iron Supplementation in Children study, a double-blind, double-dummy, individually randomized, parallel-group trial in Bangladesh, in which children, starting at 8 mo of age, received 3 mo of daily iron syrup, MNPs, or placebo. Resting brain activity was recorded using EEG immediately after intervention (month 3) and after a further 9-month follow-up (month 12). We derived EEG band power measures for delta, theta, alpha, and beta frequency bands. Linear regression models were used to compare the effect of each intervention with that of placebo on the outcomes. RESULTS: Data from 412 children at month 3 and 374 at month 12 were analyzed. At baseline, 43.9% were anemic and 26.7% were iron deficient. Immediately after intervention, iron syrup, but not MNPs, increased the mu alpha-band power, a measure that is associated with maturity and the production of motor actions (iron vs. placebo: mean difference = 0.30; 95% CI: 0.11, 0.50 µV2; P = 0.003; false discovery rate adjusted P = 0.015). Despite effects on hemoglobin and iron status, effects were not observed on the posterior alpha, beta, delta, and theta bands, nor were effects sustained at the 9-month follow-up. CONCLUSIONS: The effect size for immediate effects on the mu alpha-band power is comparable in magnitude with psychosocial stimulation interventions and poverty reduction strategies. However, overall, we did not find evidence for long-lasting changes in resting EEG power spectra from iron interventions in young Bangladeshi children. This trial was registered at www.anzctr.org.au as ACTRN12617000660381.

Effects of iron supplementation on neural indices of habituation in Bangladeshi children.

BACKGROUND: Iron deficiency and anemia have been associated with poor cognition in children, yet the effects of iron supplementation on neurocognition remain unclear. OBJECTIVE: We aimed to examine the effects of supplementation with iron on neural indices of habituation using auditory event-related brain potentials (ERPs). METHODS: This substudy was nested within a 3-arm, double-blind, double-dummy, individual randomized trial in Bangladesh, in which 3300 8-mo-old children were randomly selected to receive 3 mo of daily iron syrup (12.5 mg iron), multiple micronutrient powders (MNPs) (including 12.5 mg iron), or placebo. Children were assessed after 3 mo of intervention (mo 3) and 9 mo thereafter (mo 12). The neurocognitive substudy comprised a randomly selected subset of children from the main trial. Brain activity elicited during an auditory roving oddball task was recorded using electroencephalography to provide an index of habituation. The differential response to a novel (deviant) compared with a repeated (standard) sound was examined. The primary outcome was the amplitude of the mismatch response (deviant minusstandard tone waveforms) at mo 3. Secondary outcomes included the deviant and standard tone-evoked amplitudes, N2 amplitude differences, and differences in mean amplitudes evoked by deviant tones presented in the second compared with first half of the oddball sequence at mo 3 and 12. RESULTS: Data were analyzed from 329 children at month 3 and 363 at mo 12. Analyses indicated no treatment effects of iron interventions compared with placebo on the amplitude of the mismatch response (iron syrup compared with placebo: mean difference (MD) = 0.07µV [95% CI: -1.22, 1.37]; MNPs compared with placebo: MD = 0.58µV [95% CI: -0.74, 1.90]) nor any secondary ERP outcomes at mo 3 or 12, despite improvements in hemoglobin and ferritin concentrations from iron syrup and MNPs in this nested substudy. CONCLUSION: In Bangladeshi children with >40% anemia prevalence, iron or MNP interventions alone are insufficient to improve neural indices of habituation. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTRN12617000660381.