08/08/2025
🧠 A Sixth Sense? Gut Bacteria Communicate Directly with the Brain, Study Finds
In a groundbreaking discovery, scientists at Duke University have identified a previously unknown neural pathway that allows gut bacteria to send real-time signals to the brain—reshaping how we understand appetite, behavior, and even mental health.
Published in Nature (July 23, 2025), the study reveals a newly named system: the neurobiotic sense. This “sixth sense” hinges on neuropods—specialized sensory cells in the gut that detect microbial activity. These cells respond to flagellin, a protein released by certain gut bacteria, and instantly relay signals to the brain through the vagus nerve. The result? A direct, almost reflex-like response telling the brain to stop eating.
This effect was tested in mice, where administration of flagellin decreased appetite—unless the animals lacked the TLR5 receptor, which acts like an antenna for microbial signals. Without it, the brain never got the message, leading to overeating.
The implications are vast. This study suggests that our gut microbiome may influence not just digestion, but real-time behaviors, emotional states, and possibly psychiatric conditions. By tweaking the gut flora or targeting these neural pathways, future therapies may treat obesity, depression, or anxiety without needing to act directly on the brain.
🧬 We’ve long known that the gut and brain are connected—but this is the first direct evidence of gut microbes shaping behavior through a fast, dedicated neural circuit.
Source:
“A gut sense for a microbial pattern regulates feeding” by Winston W. Liu et al., Nature, July 23, 2025.
