The research, published today in Nature Communications, found that improvements in nutrition and household sanitation of children in rural Zimbabwe have little effect on a child's gut microbiome and thus, growth and development, and that genetic function of gut microbes in early life – rather than the types of microbes present in the gut – can predict how well a child is growing or will grow in the coming months.
This is one of the first studies to examine how the gut microbiome develops in low- and middle-income countries. The gut microbiome is a collective term for the trillions of different microbes living within the human gut, which are essential for developmental processes in early life, such as building immunity, hormone production and metabolism of certain nutrients. Until now, most of the research on the gut microbiome's role in child development is from high-income settings, not in low- and middle-income countries, where childhood infections and mortality are much higher, and where undernutrition affects more than 1 in 5 children.
The study was carried out by researchers from Queen Mary University of London, the University of British Columbia and Devil's Staircase Consulting, Canada. The researchers used metagenome sequencing technologies to analyse the gut microbiome of 335 children from rural Zimbabwe, aged 1 to 18 months.
The children were given two interventions as part of The Sanitation Hygiene Infant Nutrition Efficacy (SHINE) randomised control trial. The first intervention was improvement to infant and young-child feeding. This included providing a nutritional supplement called 'nutributter' from 6-18 months of age. The second intervention was improvement to household water, sanitation, and hygiene. This started during pregnancy, and included building new pit latrines, handwashing stations, providing chlorinated drinking water and dedicated child playpens.
Surprisingly, the results showed that these interventions had very little effect on the children's gut microbiomes, suggesting that more intensive interventions are required to alter the microbes that colonise the infant gut in early life in these settings.
The researchers also found that genetic functions of the gut microbes, such as B vitamin metabolism, can predict how well a child is growing, or will grow, in the following months. As child growth is strongly associated with immune development, brain development and other developmental processes, this new microbiome data provides a new target for interventions to optimise these growth and developmental pathways in children at risk.
First author Dr Ruairi Robertson from Queen Mary University of London said:
"This study provides the scientific community with a very large resource of gut microbiome data from children in a rural, non-Western setting throughout early childhood, which will allow researchers around the world to analyse and compare with similar datasets from children in high-income settings.
"This study also provides important data for public health in low-and-middle income countries where early-life infections, diarrheal disease, child mortality and undernutrition are much more common."
The study was funded by the Bill & Melinda Gates Foundation, the United Kingdom Department for International Development, the Wellcome Trust, the Swiss Agency for Development and Cooperation, the US National Institutes of Health, and UNICEF.
