Prebiotics increase iron absorption and reduce the adverse effects of iron on the gut microbiome and inflammation: a randomized controlled trial using iron stable isotopes in Kenyan infants.

BACKGROUND

Iron fortificants tend to be poorly absorbed and may adversely affect the gut, especially in African children.

OBJECTIVE

We assessed the effects of prebiotic galacto-oligosaccharides/fructo-oligosaccharides (GOS/FOS) on iron absorption and gut health when added to iron-fortified infant cereal.

METHODS

We randomized Kenyan infants (n=191) to receive daily for 3 weeks a cereal containing iron and either 7.5g GOS/FOS (7.5g+iron group), 3g (3g+iron group) GOS/FOS, or no prebiotics (iron group). A subset of infants in the two prebiotic+iron groups (n=66) consumed 4 stable iron isotope labelled test meals without and with prebiotics, both before and after the intervention. Primary outcome was fractional iron absorption (FIA) from the cereal with or without prebiotics regardless of dose, before and after 3 weeks of consumption. Secondary outcomes included: fecal gut microbiota, iron and inflammation status, and effects of prebiotic dose. We registered the study at Clinicaltrials.gov(NCT03894358).

RESULTS

Median(25th-75th percentiles) FIAs from meals before intervention were: 16.3%[8.0-27.6] without prebiotics versus 20.5%[10.4-33.4] with prebiotics (Cohen's d=0.53; P<0.001). FIA from the meal consumed without prebiotics after intervention was 22.9%[8.5-32.4], 41% higher than from the meal without prebiotics before intervention (Cohen's d=0.36; P=0.002). FIA from the meal consumed with prebiotics after intervention was 26.0%[12.2-36.1], 60% higher than from the meal without prebiotics before intervention (Cohen's d=0.45; P=0.007). After 3 weeks, compared to the iron group: (i) Lactobacillus abundances were higher in both prebiotic+iron groups (P<0.05); (ii) Enterobacteriaceae abundances (P=0.022) and the sum of pathogens (P<0.001) were lower in the 7.5g+iron group; (iii) the abundance of bacterial toxin-encoding genes was lower in the 3g+iron group (FDR<0.05); (iv) fecal pH (P<0.001) and calprotectin (P=0.033) were lower in the 7.5g+iron group.

CONCLUSIONS

Adding prebiotics to iron-fortified infant cereal increases iron absorption and reduces the adverse effects of iron on the gut microbiome and inflammation in Kenyan infants.

Informations de copyright

Copyright © 2023. Published by Elsevier Inc.

Déclaration de conflit d'intérêts

Conflicts Of Interest MD, IK, GR and RBS are Danone Nutricia Research employees. Other authors have no conflict of interest.