Scientists have long puzzled over why some children are afflicted by malnutrition but not others, even those in the same household who eat the same foods.
The study of young twins in Malawi, in sub-Saharan Africa, led by Washington University School of Medicine in St Louis found that dysfunctional communities of gut microbes conspire with a poor diet to trigger malnutrition.
The discovery is bolstered by additional studies in mice, showing that gut microbes transplanted from malnourished children cause dramatic weight loss and alter metabolism when the animals are fed a nutrient-poor diet.
"The gut microbes of malnourished children and malnourished mice do not appear to mature along a normal, healthy trajectory," said senior study author Jeffrey Gordon, director of the Center for Genome Sciences & Systems Biology.
"Feeding the children and the mice a high-calorie, nutrient-rich food had a temporary, beneficial effect on their gut microbes, but not enough to repair the dysfunction. Our results suggest we need to devise new strategies to repair gut microbial communities so these children can experience healthy growth and reach their full potential," Gordon said.
The new study followed 317 sets of twins in Malawi for the first three years of their lives. During this time, half of the twin pairs remained healthy, and in the others, either one or both twins developed malnutrition.
While the standard treatment to reduce deaths from the condition has been a peanut-based, nutrient-rich therapeutic food, the new study found that the therapeutic food only has a transient effect on the gut microbes.
Once the therapeutic food is discontinued, the community of microbes in the intestine and their genes revert to an immature state, in the children and in the mice.
"We are exploring whether it is possible to supplement the therapeutic food with beneficial gut bacteria from healthy children, as a treatment to repair the gut microbiome," Gordon said in a statement.
"We hope that these studies will provide a new way of understanding how the gut microbiome and food interact to affect the health and recovery of malnourished children," he added.
The study was published in the journal Science.
