Nutrition and the Gut Microbiota in 10- to 18-Month-Old Children Living in Urban Slums of Mumbai, India

Abstract

In this cross-sectional study, we describe the composition and diversity of the gut microbiota among undernourished children living in urban slums of Mumbai, India, and determine how nutritional status, including anthropometric measurements, dietary intakes from complementary foods, feeding practices, and micronutrient concentrations, is associated with their gut microbiota. We collected rectal swabs from children aged 10 to 18 months living in urban slums of Mumbai participating in a randomized controlled feeding trial and conducted 16S rRNA sequencing to determine the composition of the gut microbiota. Across the study cohort, Proteobacteria dominated the gut microbiota at over 80% relative abundance, with Actinobacteria representation at <4%, suggesting immaturity of the gut. Increased microbial α-diversity was associated with current breastfeeding, greater head circumference, higher fat intake, and lower hemoglobin concentration and weight-for-length Z-score. In redundancy analyses, 47% of the variation in Faith’s phylogenetic diversity (Faith’s PD) could be accounted for by age and by iron and polyunsaturated fatty acid intakes. Differences in community structure (β-diversity) of the microbiota were observed among those consuming fats and oils the previous day compared to those not consuming fats and oils the previous day. Our findings suggest that growth, diet, and feeding practices are associated with gut microbiota metrics in undernourished children, whose gut microbiota were comprised mainly of Proteobacteria, a phylum containing many potentially pathogenic taxa. IMPORTANCE The impact of comprehensive nutritional status, defined as growth, nutritional blood biomarkers, dietary intakes, and feeding practices, on the gut microbiome in children living in low-resource settings has remained underreported in microbiome research. Among undernourished children living in urban slums of Mumbai, India, we observed a high relative abundance of Proteobacteria, a phylum including many potentially pathogenic species similar to the composition in preterm infants, suggesting immaturity of the gut, or potentially a high inflammatory burden. We found head circumference, fat and iron intake, and current breastfeeding were positively associated with microbial diversity, while hemoglobin and weight for length were associated with lower diversity. Findings suggest that examining comprehensive nutrition is critical to gain more understanding of how nutrition and the gut microbiota are linked, particularly in vulnerable populations such as children in urban slum settings.

Roles of gut microbiota and metabolites in overweight and obesity of children

“…There is a high abundance of Proteobacteria in the feces of obese children, and these bacteria have a significant positive correlation with BMI levels ( 41 , 42 ). Proteobacteria are also relatively abundant among malnourished children and contain many potentially pathogenic species that induce immature intestines or potentially high inflammatory burdens ( 66 ). Of note, physical exercise significantly reduces the abundance of Proteobacteria in obese children ( 67 ).…”

Nurturing the Early Life Gut Microbiome and Immune Maturation for Long Term Health

“…In Australian infants aged 6-24 months, dairy intake was positively associated with the Firmicutes to Bacteroidetes ratio but was inversely associated with microbial species richness and diversity [143]. In a recent study of Indian slum-dwelling infants aged between 10 and 18 months, a positive association of fat and iron intake on alpha diversity was observed [144]. In addition, a log ratio of Lactococcus to Anaerococcus was significantly higher in the group who reported consuming oils and fats.…”

A randomized trial of iron- and zinc-biofortified pearl millet-based complementary feeding in children aged 12 to 18 months living in urban slums

“…Additionally, a factor that may be impacting our results is the baseline gut microbiome in this population, which has been shown to influence response, for example the postprandial glucose response, to dietary interventions in adults [58]. From a preliminary analysis in a subset of children in this cohort, the gut microbiome varied in composition and diversity depending on nutritional status, prior to intervention [59]. There is limited literature on the effect of biofortified crops on the gut microbiome in humans; however, early research in animals such as Gallus gallus have shown positive effects, such as increases in short-chain fatty acids, by consuming iron-and zincbiofortified crops such as common beans [60].…”