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Understanding bone turnover markers, what they can reveal, and why context matters.
If you’ve been diagnosed with osteopenia or osteoporosis, you probably want answers to two important questions: Am I losing bone, and are the things I’m doing to support my bones actually working?
A DEXA scan measures bone mineral density, but what if we could also look at what’s happening inside the bone remodeling process?
In Episode 187 of Stronger Bones Lifestyle, I welcomed back Dr. Andy Bush, orthopedic surgeon and chemist, to discuss bone turnover markers, including CTX, P1NP, and alkaline phosphatase.
These blood tests are generating interest among women looking for more information about their bone health. But understanding what they tell us—and what they don’t—is essential.
What Are Bone Turnover Markers?
Your bones are living tissue. They continually undergo remodeling, with old bone being broken down and new bone being formed.
Bone turnover markers are laboratory measurements that provide information about these processes.
Dr. Bush explained three markers in particular:
- CTX: A marker associated with bone breakdown.
- P1NP: A marker associated with bone formation.
- Alkaline phosphatase: A measurement that can provide additional information about bone activity. Bone-specific alkaline phosphatase is one form used in bone health assessment.
Another marker, NTX, is also associated with bone breakdown.
These tests can help clinicians understand aspects of bone turnover, but they don’t provide a complete picture of your bone strength or fracture risk.
Timing and Context Matter
One of the most important points Dr. Bush made was that CTX results can be affected by how and when the test is performed.
He explained that CTX is generally collected in the morning after fasting. Recent vigorous exercise may influence the result, and biotin supplementation may also interfere with some laboratory measurements.
That means a number on a lab report shouldn’t automatically cause you to worry.
An elevated result doesn’t necessarily mean something is seriously wrong. Bone turnover can fluctuate, and a clinician may need to consider other laboratory findings, medical conditions, recent fractures, and the circumstances surrounding the test.
A single result is a piece of information—not a diagnosis.
Can These Tests Tell You Whether Your Bone Health Plan Is Working?
This is where the conversation gets especially interesting.
Many women want to know whether their nutrition, supplements, exercise program, or other lifestyle changes are improving their bones.
Dr. Bush discussed how CTX and P1NP may provide useful information about bone breakdown and formation. However, he emphasized that the evidence is still evolving.
He also addressed proposed ratios between these markers that some people discuss online. At the time of this conversation, he said there wasn’t sufficient evidence to establish those ratios as reliable predictors of fractures.
The ultimate goal isn’t simply to change a laboratory number. It’s to prevent fractures and maintain strength, function, and quality of life.
Look at the Whole Picture
We also discussed the importance of muscle strength, balance, nutrition, digestion, and overall health.
These factors matter because bone health isn’t just about what appears on a scan or blood test. Your ability to build and maintain muscle, absorb nutrients, move confidently, and recover from injury is part of the bigger picture.
If you’re considering bone turnover testing, work with a knowledgeable healthcare professional who can interpret your results in context.
My Takeaway
I know how tempting it is to look for a test that will tell us exactly what’s happening inside our bones.
We’re looking for certainty—and that’s understandable.
But these tests are tools, not crystal balls. Ask questions, stay curious, and avoid making major decisions based on a single number.
Your goal is stronger bones and fewer fractures, not simply better-looking lab results.
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Frequently Asked Questions (FAQs)
Oxalates, also known as oxalic acid, are naturally occurring compounds found in many plants, vegetables, and fruits. They are part of a plant’s defense mechanism against predators and can be found in high concentrations in foods like spinach, rhubarb, beets, nuts, chocolate, tea, and certain beans.
Regarding bone health, oxalates can bind to minerals such as calcium in the gut, forming calcium oxalate. This compound is not easily absorbed by the body, meaning the calcium that could have been utilized for bone strengthening is instead excreted. This process can potentially lead to lower calcium availability for bone health, which can be particularly concerning for individuals at risk of osteoporosis or other bone-related issues.
However, for most women, dietary oxalates do not pose a significant threat to bone health, especially if their diet is balanced with enough calcium and they do not have a history of kidney stones.
Your gut is crucial for stronger bones for several reasons:
- Nutrient Absorption: The gut is where most nutrient absorption occurs. For bones to be healthy and strong, they need a variety of nutrients, particularly calcium, phosphorus, magnesium, and vitamin D. A healthy gut efficiently absorbs these essential nutrients from your diet and facilitates their transportation to the bones.
- Gut Microbiome and Bone Health: Research has shown that the gut microbiome (the community of bacteria living in your intestines) can influence bone density. Certain gut bacteria help in producing short-chain fatty acids (SCFAs) like butyrate, which have been shown to promote bone health. SCFAs can enhance the absorption of minerals necessary for bone strength and play a role in reducing inflammation, which can negatively affect bone health.
- Hormone Regulation: The gut helps regulate hormones that are involved in bone metabolism, including insulin, thyroid hormones, and sex hormones like estrogen. For example, estrogen is vital for bone density, and gut health can influence estrogen levels through the enterohepatic circulation, where estrogens are processed in the liver and intestines.
- Reducing Inflammation: Chronic inflammation, which can stem from poor gut health, is linked to many conditions that compromise bone strength, such as osteoporosis. A healthy gut helps to reduce systemic inflammation, protecting bones from inflammatory damage.
- Immune System Modulation: The majority of the immune system is located in the gut. An imbalance in the immune system can lead to autoimmune conditions, some of which affect the bones. Maintaining gut health helps to ensure the immune system works correctly, protecting against autoimmune reactions that could impact bone health.
In essence, maintaining a healthy gut contributes significantly to stronger bones by ensuring the effective absorption of vital nutrients, regulating hormones, reducing inflammation, and supporting a healthy immune system. Therefore, a diet rich in bone-healthy nutrients, prebiotics, and probiotics, along with lifestyle factors that promote gut health, is key to maintaining strong bones.