What your breath says about the bacteria in your gut

"Using mice and a group of 41 children, Andrew Kau, an immunologist at Washington University in St. Louis, Missouri, and his colleagues measured the levels of molecules in exhaled breath and showed how they could be used to partially predict the identity and abundance of certain gut bacteria, including one species that is associated with asthma. "The gut-microbiome composition can shape the type of compounds you see in breath," says Kau. This was suspected, he says, but "it was never certain"."

""I love the idea of using breath measurements to get more information about health," says Katrine Whiteson, a biochemist at the University of California, Irvine. "Breath is an amazing measurement because it's aggregate information from the lung and the whole body." Volatile research Scientists have long wondered about the possibility of using the chemical metabolites in breath to diagnose disease."

Measurements in mice and 41 children show levels of molecules in exhaled breath can partially predict the identity and abundance of specific gut bacteria, including species linked to asthma. Breath contains volatile metabolites produced by human cells and microbes; more than 250,000 such molecules exist, and some enter the bloodstream, reach the lungs, and diffuse into exhaled air. Breath profiling could enable noninvasive diagnostics and guide treatments for conditions influenced by gut bacteria, offering a faster, simpler alternative to stool testing. The complexity of the system presents significant analytical challenges.

Read at Nature