What if your stomach wasn’t just processing food—but also talking to your brain in real time, telling it when to put down the fork? That’s precisely what a groundbreaking study from Duke University suggests, potentially transforming how we understand human senses.
At the core of this research is flagellin, an ancient protein located in the tail-like structure of bacteria known as flagella. Scientists discovered that unique sensory cells in our intestines—called neuropods—can identify the presence of flagellin. These neuropods then communicate directly with the brain via the vagus nerve, the longest autonomic nerve in the body.
The “Gut Sense”
Published in the prestigious journal Nature, the study hints that our gastrointestinal system isn’t just a food-processing machine. It may actually contain a “neurobiotic sense”, capable of influencing eating patterns. Some experts are already referring to this as the sixth sense.
The Mechanism Explained
Neuropods are equipped with a receptor known as TLR5 (Toll-Like Receptor 5). When researchers introduced flagellin to mice, those with active TLR5 showed a reduced appetite and consumed less food. Mice lacking this receptor, however, didn’t receive the same satiety cues—and gained weight rapidly.
This means our gut microbiome is far more than a silent partner. It actively shapes our hunger, fullness, and even behavior, highlighting the powerful role of gut-brain communication.