(P27-012-24) Impact of an Iron-Biofortified Intervention on the Composition and Diversity of the Gut Microbiota Among Children in the 2nd Year of Life

Objectives: The effect of delivering iron through food-bound approaches, such as biofortified crops, on the composition or diversity of the gut microbiota has not been explored in humans. We determined the effect of 9 months’ daily consumption of meals prepared with iron/zinc-biofortified pearl millet (FeZnPM) on the gut microbiome compared to control pearl millet (CPM) in children as part of a randomized controlled feeding trial (NCT02233764) in children living in urban slums of Mumbai, India.

Methods: Children (12–18 months, N=223, hemoglobin >9 g/dL) were randomized to receive either FeZnPM- or CPM-based foods (~3 mg or 1 mg iron daily, respectively). Rectal swabs and blood samples were collected across follow-up, in addition to demographic, clinical, and anthropometric data. Shotgun metagenomic sequencing was carried out on rectal swabs, reads were aligned to the Web of Life v2 reference phylogeny, and assigned to operational genomic units (OGUs). Diversity indices and differential abundance analysis were determined using R, and random intercept models were used to examine the effect of FeZnPM on OGU abundances and diversity.

Results: There were no differences in gut microbiome composition and diversity between intervention groups at baseline. Over 9 months’ follow-up (n=82 paired samples available), random intercept models indicated that α-diversity indices increased in both groups (q < 0.05). There were 1033 total OGUs with significant fold-changes in abundance at endpoint vs. baseline. 209 unique taxa were found to be both differentially abundant at endpoint vs. baseline and to significantly change over time, most notably Fusicatenibacter saccharivorans, which decreased by ~120 fold from baseline to endpoint. There was no impact of intervention on α-diversity indices.

Conclusions: Future analyses will examine effect of intervention on functional pathways, uninvestigated potential factors influencing the changes in α-diversity and relative abundance between both groups, such as fiber intake, and examine subgroups such as children with iron deficiency at baseline. These preliminary results suggest that, unlike previously published supplementation-based approaches, FeZnPM did not adversely affect the gut microbiota in children living in urban slums of Mumbai compared to CPM.

Funding Sources: HarvestPlus, CPNH, USDA, NIH (SLH)