The effect of legume supplementation on the gut microbiota in rural Malawian infants aged 6 to 12 months

Authors: ORDIZ, M - Washington University; JANSSEN, STEFAN - University Of California, San Diego; HUMPHREY, GREG - University Of California, San Diego; ACKERMANN, GAIL - University Of California, San Diego; STEPHENSON, KEVIN - Washington University; AGAPOVA, SOPHIA - Washington University; DIVALA, OSCAR - University Of Malawi; KAIMILA, YANKHO - University Of Malawi; MALETA, KEN - University Of Malawi; ZHONG, CAROLINE - Washington University; KNIGHT, ROB - University Of California, San Diego; TREHAN, INDI - Washington University; TARR, PHILIP - Washington University; RUSCONI, BRIGIDA - Washington University; MANARY, MARK - Children'S Nutrition Research Center (CNRC)

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2020
Publication Date: 2/11/2020
Citation: Ordiz, M.I., Janssen, S., Humphrey, G., Ackermann, G., Stephenson, K., Agapova, S., Divala, O., Kaimila, Y., Maleta, K., Zhong, C., Knight, R., Trehan, I., Tarr, P.I., Rusconi, B., Manary, M.J. 2020. The effect of legume supplementation on the gut microbiota in rural Malawian infants aged 6 to 12 months. American Journal of Clinical Nutrition. 111(4):884-892. https://doi.org/10.1093/ajcn/nqaa011.
DOI: https://doi.org/10.1093/ajcn/nqaa011

Interpretive Summary: Microbes in the gut, which are determined in part by dietary fiber intake, may play an important role in normal child growth. Stool samples were tested to determine their microbial composition from Malawian infants after the children received different dietary legumes, common beans and black-eyed peas, for many months. The microbes were different in children receiving black-eyed peas. These children grew taller as well, suggesting that black-eyed peas can help children grow better by changing the microbes in the gut.

Technical Abstract: Common bean and cowpea contain about 25% protein and 25% fiber, and are recommended as complementary foods in sub-Saharan Africa. The objective of this study was to determine if a daily legume supplement given to Malawian infants aged 6 to 12 mo alters the 16S configuration of the fecal microbiota as read out by amplicon sequence variants (ASVs). This study was conducted within the context of a randomized, double-blind, controlled clinical trial to assess whether cowpea or common bean supplementation reduced intestinal permeability or increased linear growth. There were 2 village clusters in which the study was conducted. Fresh stool collections were flash frozen from 236 infants at <=6 time points. The stools were sequenced using Earth Microbiome project protocols and data were processed using Qiime and Qiita, open-source, validated software packages. a-diversity was measured using the Faith's test. The 16S configuration was characterized by determining the weighted UniFrac distances of the ASVs and comparing them using permutational multivariate ANOVA. Among the 1249 samples analyzed, the alpha-diversity of the fecal microbiome was unchanged among subjects after initiation of legume supplementation. Neither cowpea nor common bean altered the overall 16S configuration at any age. The 16S configuration differed between children with adequate and poor linear growth aged from 6 to 9 mo, but no specific ASVs differed in relative abundance. The 16S configuration differed between children with normal and abnormal intestinal permeability at 9 mo, but no specific ASVs differed in relative abundance. Among categorical characteristics of the population associated with different 16S configurations, village cluster was most pronounced. Legume supplementation in breastfed, rural African infants did not affect the structure of the gut microbial communities until the children were aged 9 mo.