Higher fiber complementary food alters fecal microbiota composition and normalizes stool form in Malawian children: a randomized trial

Abstract

Dietary fiber favorably modulates gut microbiota and may be protective against diarrhea in sub-Saharan Africa where rates in infants and young children are high. Soybean hull is high in fiber and accessible in rural Africa; however, its use in complementary feeding has not been evaluated. The objective of this study was to determine the acceptability and feasibility of a soybean, soy hull fiber, and maize (SFM) blend food; the primary outcome was compliance to the feeding protocol. Secondary outcomes were stool form and frequency, fecal microbiota composition, growth and dietary intake. In a parallel, single-blind study, children 6-36 months of age from the Lilongwe district of Malawi were randomized to receive daily SFM (n=69) or maize only (n=10) porridge (phala) for 6 months. Anthropometrics were measured monthly, and compliance, stool frequency, and stool form, weekly. At baseline, 3-month, and 6-month (study end) time points, dietary intake (24-h recall) was assessed, and fecal samples were collected. Fecal DNA was analyzed by Real-Time polymerase chain reaction (PCR) for microbes of interest and 16S rRNA gene amplicon sequencing. Mothers accessed the acceptability and feasibility of the study foods at study end. Mothers reported excellent compliance to feeding the SFM porridge, rated it more acceptable than maize, and noted improved appetite, weight, and stool consistency of their children. Stool frequency at baseline (2±1 stools/d) was unchanged with intervention; however, there were significantly fewer diarrhea-type stools reported during study months 4-6 vs. 1-3 for the SFM group, whereas no improvement was seen for the maize group. At study end, the fecal abundance of Akkermansia muciniphila was enriched in children receiving the SFM, compared to maize (p<0.05), and a trend for increased Faecalibacterium prausnitzii (p=0.07) was seen. A comparison of fecal microbiota composition using linear discriminant analysis effect size (LEfSe) showed notable differences in numerous taxa in the SFM group compared to baseline, whereas the maize comparator exhibited fewer changes. Fiber intake was higher for the SFM group, compared to maize at 6 months (13.7±3.8 vs. 8.4±4.5 g/day, p<0.01). Weight-for-height and BMI-for-age Z-scores were significantly higher for the SFM group. In young Malawian children, feeding a blend of soybean, soy hulls and maize reduced diarrhea-type stools and increased the abundance of Akkermansia muciniphila, a bacterial species involved in maintaining intestinal health, and thus may provide a feasible means of improving wellness in children in resource-poor settings through the modulation of microbiota composition.