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The gut-brain-bone axis and Biodynamic Skeletal Therapy

This is an excerpt from Unwinding Bone by Scott Sternthal.

The Gut-Brain-Bone Axis and Biodynamic Skeletal Therapy

Together with the central nervous system and the gastrointestinal tract, bone tissue is an integral part of a crucial multidirectional exchange. With its gazillions of neurons, the central nervous system is the undisputed commander in chief of the body. The gastrointestinal tract, which contains the second-largest number of (intestinal) neurons, is the “brain” of the gut, and is commonly referred to as our second brain.

Our two brains get along swimmingly; the gut transmits information to the brain about X, and the brain responds by doing Z, or the brain tells the gut something important, and the gut reacts in appropriate (and sometimes inconvenient) ways. The pathways of these conversations are traditionally referred to as the gut-brain axis. But this axis connects to a third pole: bone.

Besides providing structure to the body, bone possesses important organ-like endocrine functions, splicing the gut-brain conversation into a three-way visceral chat. In this triad, bone is more often the customer than it is the delivery person—it receives information more often than it transmits it—but it participates nonetheless. For example, the neurotransmitter serotonin is produced in the brain, but resides mainly in the gut. Serotonin impacts both the brain and the gut in diverse ways, affecting things like mood and memory and vomiting. Curiously, serotonin also exists in bone tissue, where it plays a role in bone development. But serotonin in bone is not produced by bone cells—it flows downstream from the brain to the gut and then to bone.

Bone has been shown to impact organs upstream from it, too. It was recently discovered that LCN2, a bone-derived mediator, can pass from bone into the blood and then into the hypothalamus, influencing the gut by suppressing appetite. Bone fracture can impact the central nervous system, exacerbating inflammation associated with traumatic brain injury, and so on. The conversations along the gut-brain-bone axis swing both ways—from brain to gut to bone and back again.

Therefore, bone supports and protects our two brains and is a “third” brain, of sorts. Could BST impact this exchange? To find out, let’s look at the role of bone tissue within the gut-brain-bone axis from two specific angles: as offering physical support to the axis through key bony landmarks, and as an organ—a third brain—participating in a multipronged drive toward homeostasis.

More Excerpts From Unwinding Bone

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