Not Just Nutrition: Scientists Uncover a Hidden Cause of Growth Stunting in Children

Gut bacteria associated with malnutrition and childhood stunting may be passed from mothers to their offspring and influence development even before birth, according to researchers at the Washington University School of Medicine in St. Louis.

The study, published in the journal Nature Microbiology, found that specific microorganisms in the small intestine can trigger inflammation, damage the intestinal lining, and impair the body's ability to absorb nutrients.

The researchers focused on a condition known as environmental enteric dysfunction (EED)—a chronic inflammatory disorder of the small intestine that commonly affects malnourished children. EED reduces the body's capacity to absorb essential nutrients from food and has been linked to stunted growth, weakened immunity, and impaired cognitive development.

The team analyzed gut bacterial samples from children in Bangladesh who failed to recover after receiving standard nutritional therapy. In previous research, the scientists had identified 14 bacterial species associated with inflammation and poor growth in these children.

These bacterial communities were then transplanted into laboratory mice that were fed a diet resembling that of residents of Mirpur, a district of Dhaka, where the participating children lived.

Mice receiving the inflammation-associated bacterial community developed symptoms similar to those observed in the children, including impaired growth, inflammatory changes in the blood, and damage to the intestinal lining.

One of the study's most important findings was that the bacteria affected development not only after birth but also during pregnancy. The researchers discovered that the composition of the mother's small-intestinal microbiome could influence fetal development before birth.

"The effects of this disease extend beyond the mother's intestine and may influence the developing fetus," said the study's senior author, Dr. Jeffrey Gordon.

One of the key microorganisms identified was Campylobacter concisus, a bacterium commonly found in the human mouth. While it is generally considered harmless in the oral cavity, it can become pathogenic after reaching the small intestine, where it may trigger inflammation.

The researchers emphasized that C. concisus alone does not necessarily cause disease. In germ-free mice lacking their own microbiota, the bacterium produced little to no harmful effect. This suggests that its impact depends on interactions with the broader microbial community and the surrounding intestinal environment.

The study also showed that harmful bacteria can spread between individuals. When mice carrying the inflammatory microbiome were housed with mice containing healthy bacterial communities, the disease-associated microbes were transmitted and produced similar adverse effects in the newly colonized animals.

The researchers believe these findings could help break the intergenerational cycle of malnutrition by paving the way for new therapeutic strategies. In the future, they hope to develop safe methods to modify the maternal microbiome before or during pregnancy, reducing inflammation and promoting healthier growth and development in children.