What Researchers Discovered

Scientists at Copenhagen University Hospital followed hundreds of children from birth through age 10, analyzing their gut microbiome at just one week old and tracking their attention development over time. The findings were unexpected: children with higher levels of Bifidobacterium bacteria in their first-week gut microbiome showed a 54-59% increase in odds of developing attention challenges at age 10.

But here’s where it gets really interesting. The researchers found that this relationship was partly mediated by a metabolite called indole-3-lactic acid (ILA)—a chemical produced by gut bacteria that circulates in the blood. About 21% of the effect of early gut bacteria on later attention development appeared to work through this metabolic pathway.