Intestinal microbiome, medical concept
Credit: Dr_Microbe/ iStock

An intriguing study suggests altering the balance of gut microbes could improve children’s health, particularly for those in low-income countries.

Changing gut microbe composition appeared to influence growth, a key measure of health, among children living in rural Zimbabwe according to the findings in Nature Communications.

The gut microbiome was not altered by improvements to diet or hygiene, suggesting more intensive interventions are required to change microbe colonization early on in life.

But having an HIV-positive mother and being exposed to the virus in utero was associated with imbalances in the gut microbiome, even among children who were not themselves infected.

Study first author Ruairi Robertson told Inside Precision Medicine that current interventions targeting child undernutrition largely relied upon the provision of simple nutrients including sugars, vitamins and minerals.

While these are beneficial, they are largely absorbed in the small intestine and do not impact on the gut microbiome which is most dense in the large intestine.

“This research adds to some existing literature showing the importance of a healthy gut microbiome development for child growth,” he said.

“Future interventions that target the gut microbiome, in addition to simple nutrients, may therefore help to reduce the burden of child undernutrition and associated outcomes around the world.”

Several studies have linked the gut microbiome of infants to asthma, obesity and other conditions common in the industrialized world.

However, data are lacking in low-income settings, where malnutrition, diarrheal disease and infections are common.

Using modern metagenome sequencing, the team used more than 800 stool samples to map the gut microbiomes of 335 children, aged between one and 18 months, from rural Zimbabwe of whom a third had stunted growth.

All participants were enrolled in the Sanitation, Hygiene, Infant Nutrition Efficacy (SHINE) Trial, a randomized study to examine whether improved water, sanitation and hygiene (WASH) or infant and young child feeding (IYCF) could combat stunted growth.

Results showed that intestinal microbiota maturation in the children was driven strongly by age.

As with Western settings, microbiomes were dominated by Bifidobacteria in early infancy followed by Faecalibacterium and Prevotella following weaning.

The trial showed that WASH had no effect on stunting and IYCF reduced this by approximately a fifth. But surprisingly, neither intervention had a strong effect on the infant gut microbiome.

In contrast, children born to HIV-positive mothers had over-mature, over-diverse gut microbiomes, and a depletion of commensal Bifidobacteria and amino acid biosynthetic pathways.

The study showed that taxonomic composition of the gut microbiome poorly predicted growth.

However, functional features of the microbiome were better able to predict current and future growth, with metagenomic pathways involved in B vitamin metabolism and nucleotide biosynthesis amongst the most predictive pathways.

The researchers say their results raise the intriguing possibility that altered succession and assembly of the infant gut microbiome could drive some of stunting, mortality, and cognitive impairment observed among children who are HIV-exposed but uninfected (CHEU).

They suggest: “Novel therapeutic approaches targeting the gut microbiome may mitigate the poor clinical outcomes that are observed in CHEU, a growing population of children in sub-Saharan Africa.”

Also of Interest