Gut bacteria linked to undernutrition recovery

International researchers have successfully tested a new approach to treating undernourished children by developing a diet designed to restore the activity of beneficial gut bacteria.

Writing in the journal Science, they report that the bacteria activate specific biochemical pathways that increase the levels of essential amino acids and several growth factors, triggering bone growth and weight gain.

The diets were developed using pig and mouse models and data from both healthy and malnourished cohorts of children from Bangladesh. 

“The designed diets entrained maturation of the children’s microbiota and put their metabolic and growth profiles on a healthier trajectory,” the authors write. 

The international team was led by Jeffrey Gordon from Washington University School of Medicine, US, and included researchers from the US, India, Bangladesh, Russia, South Africa, Peru and Saudi Arabia.

Studies have shown that gut microbes play a vital role in the digestion, absorption, metabolism and transformation processes of dietary proteins in the intestines, and that any disruption in the normal population of microbes can lead to undernutrition and other metabolic disorders. 

However, the researchers say, current therapeutic foods given to children with acute malnutrition – such as khichuri-halwa and milk-suji in Bangladesh – “have not been formulated based on knowledge of how they affect the developmental biology of the gut microbiota”.

“Moreover, they are largely ineffective in ameliorating the long-term sequelae of malnutrition that include persistent stunting, neurodevelopmental abnormalities, and immune dysfunction,” they add.

Gordon and colleagues prepared a diet based on foods eaten by healthy Bangladeshi children with normal gut microbes – including chickpeas, bananas and tilapia. They then transplanted specific bacteria from the gut of malnourished children into mice and fed these mice the new diet. 

They found that the mice showed higher levels of essential amino acids in their large intestines than those that consumed khichuri-halwa and milk-suji.   

The diet also increased the levels of specific microbial metabolites that are known to suppress inflammation and protect nerve cells and elevated the serum levels of insulin-like growth factor-1 that has been associated with increased bone formation, the researchers say. 

As malnourished children tend to live in poorer communities, the researchers then tried replacing tilapia with cheaper soy and peanut flours and tested their efficiency first in piglets, and then in a small group of malnourished children. 

The piglets consuming milk power supplemented with flours made from soy, chickpea, peanut and banana showed greater weight gain than those that ate only flours made from chickpea and soy, as well as an increase in the population of beneficial bacteria in their gut. 

The diet also induced bone growth in the children.