The Gut Microbiota: A Promising Target in the Relation between Complementary Feeding and Child Undernutrition

Nutritional status of infants and young children in India across three decades: Analysis of five national family health surveys

BACKGROUND

Three indicators of early childhood undernutrition and associated factors are evaluated among under-5 children in five National Family Health Surveys in India spanning 1992 to 2021.

METHODS

Data for 533,495 children under 5 years of age (U-5) were analysed in the context of three commonly used indicators of early childhood undernutrition - wasting, stunting and underweight. In addition to descriptive and inferential statistics, binary logistic regression was used to estimate the effects of specific explanatory factors on the three indicators using adjusted odds ratios.

RESULTS

Over the three-decade interval, stunting was reduced by 22.1% in boys and 20.9% in girls, followed by underweight, 19.3% in boys and 17.4% in girls; wasting, in contrast, was reduced to a considerably lesser extent, 2.8% in boys and 0.9% in girls. Demographic, maternal and socioeconomic factors were associated with the incidence of early childhood undernutrition, specifically among young mothers and those with less education in low-income families, and among children from Scheduled Tribes or Scheduled Castes. Stunting and underweight declined significantly over the past three decades while wasting changed negligibly. The disparity in the occurrence of early childhood undernutrition was apparent throughout socioeconomic categories and regions of India.

CONCLUSIONS

The results highlight the need for special programs aimed at reducing waste among children and also the need for customized initiatives focused on the improvement of maternal education and wealth in addition to other ancillary factors related to regional variation.

Gut microbiome development and childhood undernutrition

Forty-five percent of deaths among children under 5 years of age are associated with undernutrition. Globally, almost 200 million children exhibit the two major forms of undernutrition-wasting (low weight-for-height) or stunting (low height-for-age), with many affected by both. Undernutrition is not due to food insecurity alone. Growing evidence indicates that perturbed postnatal gut microbiome development contributes to its pathogenesis. This perspective focuses on defining and repairing these defects in gut microbiome development. We describe an approach that involves the analysis of well-phenotyped human cohorts, followed by preclinical studies using gnotobiotic animals colonized with microbiota from these cohorts. Additionally, these models can be used to identify therapeutic targets and candidates that can then be tested clinically. Furthermore, introducing pretreatment microbiota from trial participants into gnotobiotic animals and re-enacting trial conditions allow mechanisms to be dissected. We highlight these recent advances as well as gaps in existing knowledge that present opportunities for future research.

Effect of Lactobacillus rhamnosus MN-431 Producing Indole Derivatives on Complementary Feeding-Induced Diarrhea Rat Pups Through the Enhancement of the Intestinal Barrier Function

SCOPE

Many infants suffer from complementary feeding-induced diarrhea (CFID). Studies have shown that intestinal microbes can enhance the intestinal barrier and prevent diarrhea by producing indole derivatives that promote pregnane X receptor (PXR) expression.

METHODS AND RESULTS

In this study, the indole test and determination of the PXR concentration are performed on tryptophan broth cultures of 320-suspected Lactobacillus and Enterococcus strains. Four strains that produce indole derivatives that promote the expression of PXR are screened as potential functional probiotics. Both Lactobacillus rhamnosus MN-431 (L. rhamnosus MN-431) and Lactobacillus oris FN-448 (L. oris FN-448) can colonize the intestine of rat pups, and L. rhamnosus MN-431 can significantly decrease the incidence of diarrhea and intestinal permeability in rat pups. Using real-time qPCR and the analysis of the intestinal morphology using immunohistochemistry, it is observed that the metabolized tryptophan from L. rhamnosus MN-431 can reduce small intestinal mucosal damage by stimulating PXR/NF-κB signaling and activating PXR and aryl hydrocarbon receptor. The intestinal barrier is also enhanced by promoting the expression of tight junction proteins such as Occludin and zonula occludens-1 in baby rats.

CONCLUSION

The results demonstrate that L. rhamnosus MN-431 can metabolize tryptophan to prevent infantile CFID by promoting the expression of PXR.

Micronutrient supplements can promote disruptive protozoan and fungal communities in the developing infant gut

Supplementation with micronutrients, including vitamins, iron and zinc, is a key strategy to alleviate child malnutrition. However, association of gastrointestinal disorders with iron has led to ongoing debate over their administration. To better understand their impact on gut microbiota, we analyse the bacterial, protozoal, fungal and helminth communities of stool samples collected from a subset of 80 children at 12 and 24 months of age, previously enrolled into a large cluster randomized controlled trial of micronutrient supplementation in Pakistan (ClinicalTrials.gov identifier NCT00705445). We show that while bacterial diversity is reduced in supplemented children, vitamins and iron (as well as residence in a rural setting) may promote colonization with distinct protozoa and mucormycetes, whereas the addition of zinc appears to ameliorate this effect. We suggest that the risks and benefits of micronutrient interventions may depend on eukaryotic communities, potentially exacerbated by exposure to a rural setting. Larger studies are needed to evaluate the clinical significance of these findings and their impact on health outcomes.