Bone Metabolism: What Bone Actually Does

Part 2 of an ongoing series

Part 1 covered how osteoporosis gets tested and diagnosed, and closed with a look at bone’s connection to brain health through the research I co-authored. Part 2 stays with that same idea: bone as more than structure. It goes further into bone metabolism, what bone actually does, and what happens when that work gets disrupted.

Same rules as before: published findings are cited, my own clinical observations are labeled From practice, and my opinions or working hypotheses are labeled Editorial.

What Bone Actually Does

Ask most people what bone is for, and the answer stops at structure and support. That’s true, but it’s a small fraction of the picture. Bone is living tissue with several jobs most of us were never taught to associate with it.[1]

  • Structure and movement. The job everyone knows: bone is the scaffolding for movement, it protects organs, and it anchors muscle so we can bear load.
  • Blood and immune cell production. Bone marrow is the manufacturing site for red blood cells, platelets, and immune cells.[2]
  • A metabolic role. Beyond structure, bone metabolism reaches into the body’s broader metabolism, and researchers are still working out exactly how far that influence extends into things like energy and blood sugar regulation.[3,4]
  • An immune role. Bone cells and immune cells share a common origin, and they signal back and forth: the basis of a field called osteoimmunology.[5]

Editorial. The reason I put these on the table isn’t to turn this into a biology lecture. It’s to make one point: when bone quality and the joints around it break down, what’s at stake isn’t only physical.

Bone metabolism is wired into the rest of the body, so a bone problem often signals something happening underneath the surface. Hold onto that as we get into the mechanics of how bone loss actually happens.

Bone’s Second Job: Buffering, Not Just Building

Most people picture bone health as purely structural: is it dense enough, is it going to fracture. But bone carries two burdens, not one.

The first is its own upkeep: the constant remodeling cycle that keeps the tissue alive and strong. The second is a job most people never learn bone does at all. The skeleton is one of the body’s reservoirs for neutralizing excess acid. When the body needs to buffer an acid load, it can draw on bone mineral to do it, and that borrowing comes at the expense of bone quality.[6]

Separately, chronic inflammation and the acidic environment that comes with it are established drivers of bone breakdown. Acid conditions rev up the cells that resorb bone and quiet the cells that build it,[7] and long-running inflammation pushes the same direction across a range of real diseases.[8]

Editorial. Putting those two findings side by side is where I think the real picture emerges, even though neither body of research states it as one mechanism.

If bone helps buffer the body’s acid load, and inflammation-driven acidity independently speeds up bone breakdown, then a body running a chronic stress and inflammation cascade is asking bone to do two competing jobs at once: neutralize the acid, and maintain its own structure. When that demand never lets up, the maintenance side loses the competition for resources. That’s my synthesis connecting the two findings, not a claim that either paper spells out this chain directly.

The Endplate: A Gateway That Breathes

Spine care puts enormous focus on the disc, for good reason. But the disc is avascular. It has no blood supply of its own. It feeds by diffusion, drawing nutrients in and pushing waste out through the thin layer of bone above and below it: the vertebral endplate.[9]

From practice. I think of the endplate as a gateway that breathes. With every load and unload, fluid and nutrients move across it in and out of the disc, and that exchange is how the disc stays alive. That’s exactly why the endplate’s structural health is also a physiology question. When the endplate calcifies, part of the same broader inflammatory and degenerative cascade, it stops breathing freely. The gateway stiffens, diffusion drops, and the disc it was feeding starts to starve.[10] 

The calcification can be driven locally, by one segment’s arthritic change, or systemically, by a body-wide inflammatory process, and the two often show up together on the same level. Endplate quality can be assessed across DEXA, X-ray, and MRI.[11]

This is the throughline of the whole post: the structure and the physiology are the same tissue doing different jobs. Compromise the structure, and you quietly compromise the biology it was supporting.

Where Posture Fits Into All of This

This is where the “hold onto that” from earlier comes back around.

When we work to build posture, we are protecting alignment and range of motion. That’s the visible goal, and it matters. But we are also expressing the underlying metabolism we just walked through. Correct the structure, and you are not adjusting scaffolding in isolation. You are engaging the same tissue that manufactures blood cells, signals to the immune system, and buffers the body’s acid load.

Editorial. The circle of interdependent functions only grows from there. Exercise depends on bone for its mechanical foundation, and at the same time, load-bearing exercise is one of the primary stimuli that strengthens bone. That same movement also promotes blood flow, and healthy bone architecture in turn protects the marrow and vascular space that blood flow depends on.

I think the honest word for what’s happening here is resilience, not just density or alignment. Structure, blood, metabolism, and immune function are not four separate systems that happen to share the same tissue. They form one interdependent loop, and posture work is one of the few interventions that touches every point of that loop at once. That’s the case I want to make as this series continues into Part 3, where we get into exactly how that loading relationship works.

Where We’re Headed

Part 3 picks up where the metabolic thread leaves off: the hormonal drivers behind bone loss, and how they tie back to the brain-and-bone connection the research pointed to. As always, no rush. This is a subject that rewards the long version.

Dr. Anish Bajaj, DC, is the founder of Well Rooted Health (Westfield, NJ) and Well Rooted Chiropractic (NYC), a peer-reviewed researcher, and a 25-year practitioner focused on the intersection of posture, nutrition, cognition, and sleep.

References

  1. Florencio-Silva R, Sasso GR, Sasso-Cerri E, Simões MJ, Cerri PS. Biology of Bone Tissue: Structure, Function, and Factors That Influence Bone Cells. BioMed Research International. 2014.
  2. Swann JW, Olson OC, Passegué E. Made to order: emergency myelopoiesis and demand-adapted innate immune cell production. Nature Reviews Immunology. 2024.
  3. Lecka-Czernik B, Rosen CJ, Napoli N. The role of bone in whole-body energy metabolism. Nature Reviews Endocrinology. 2025.
  4. Smith C, Lin X, Parker L, et al. The Role of Bone in Energy Metabolism: A Focus on Osteocalcin. Bone. 2024.
  5. Tsukasaki M, Takayanagi H. Osteoimmunology: evolving concepts in bone–immune interactions in health and disease. Nature Reviews Immunology. 2019.
  6. Bushinsky DA, Krieger NS. Effects of Acid on Bone. Kidney International. 2022.
  7. Arnett TR. Acidosis, Hypoxia and Bone. Archives of Biochemistry and Biophysics. 2010.
  8. Paccou J, Tsourdi E, Anastasilakis AD, Lems WF, Compston J. Pathophysiology, diagnosis and management of secondary osteoporosis. Nature Reviews Endocrinology. 2026.
  9. Theodore N. Degenerative Cervical Spondylosis. New England Journal of Medicine. 2020.
  10. Ren P, Chen P, Reeves RA, et al. Diffusivity of Human Cartilage Endplates in Healthy and Degenerated Intervertebral Disks. Journal of Biomechanical Engineering. 2023.
  11. Liao H, Yang H, He P, et al. Comparison of the predictive value of MRI-based cervical endplate bone quality and cervical vertebral bone quality scores for the progression of cervical disc degeneration. European Spine Journal. 2026.

Ready to understand what your spine and posture are telling you?
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