Scientists May Have Found Humanity’s Sixth Sense—In Our Gut
An ancient bacterial protein known as “flagellin” signals to our neurons in our gut when we’re full, directly showing how our microbiome and brain communicate.
Science textbooks typically describe humans as having five senses—seeing, smelling, hearing, seeing, and touching. While it’s true these are the most outward and obvious senses, they’re far from the only ones. For one, there’s proprioception, which describes the body’s ability to sense its position and movement in space—that may not seem like a big deal, but if you live without it, poor balance is only the beginning of your problems.
And now, a new study led by scientists at Duke University suggests that there’s yet another sense lurking in our gut. This is the home of the microbiome—a collection of bacteria, fungi, viruses, and archaea that impact our immune system, our digestion, and even our mental health. And it’s within this microbiome that bacterial flagella (the tail-like structure bacteria use to swim) release an ancient protein known as “flagellin.” This new study, published yesterday in the journal Nature, describes the flagellin as the method through which neuropods, essentially neurons in your gut, regulate appetite.
According to the scientists, neuropods contain a receptor known as “toll-like receptor 5,” or TLR5, which then sends impulses to the brain via the vagus nerve—the gut-brain information highway that is also the longest nerve of the body’s autonomic nervous system. This shows how microbes living in our gut can communicate with the human brain.
