Building bone and joint strength: The role of vitamin D3/K2, magnesium, and omega-3 in long-term skeletal health

Bone health isn’t something many people think about or talk about—until something breaks. Unlike weight gain or fatigue, bone loss doesn’t come with noticeable daily symptoms. Instead, it progresses silently, sometimes over decades, until a DEXA scan or an unexpected fracture reveals the damage that’s already been done.

For most people, the default response is to reach for a calcium supplement and hope for the best. But calcium alone is only a small piece of a much larger story. 

At the end of the day, bone is living, dynamic tissue; it’s constantly being broken down and rebuilt through a process called remodeling. And the nutrients that govern that process are some of the most deficient in the modern diet.

In fact, skeletal health depends less on how much calcium you consume and more on whether your body has the tools to put that calcium where it belongs. With the right biomarker data and a targeted nutrient strategy, bone and joint strength can be maintained, no matter your age. 

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Why is calcium not enough?

Your skeleton is in a constant state of renovation. Specialized cells called osteoblasts lay down new bone tissue. In contrast, osteoclasts break down old or damaged bone. 

In a healthy system, these two forces stay in balance. But when key nutrients are missing—or when chronic inflammation tips the scales—osteoclast activity begins to outpace new bone formation, and bone density declines.

And this is why calcium alone isn’t enough. Without adequate vitamin D3, your body can’t absorb calcium efficiently. Without vitamin K2, absorbed calcium has no reliable mechanism to reach your bones—and may instead deposit in your arteries and soft tissues. On top of this, magnesium and omega-3s also play a part here (more on this below).

Overall, skeletal decline results from a collapsing system, which may have roots in your diet.

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Nutrients that support skeletal strength

With comprehensive bloodwork, Welle identifies the specific deficiencies driving bone and joint concerns, then builds a personalized protocol to address them. This approach ultimately targets the upstream nutrients that enable efficient and effective calcium metabolism.

Vitamin D3 and K2

Vitamin D3 and K2 are arguably the most important—and most overlooked—partnership in bone health. Vitamin D3 increases calcium absorption from the gut, ensuring the mineral actually enters your bloodstream. But absorption is only half the equation. 

Vitamin K2 activates a protein called osteocalcin, which binds calcium and directs it into bone tissue where it’s needed. Without K2, supplementing with D3 and calcium can actually backfire. 

Excess circulating calcium with nowhere to go may contribute to arterial calcification—a risk factor for cardiovascular disease. 

Magnesium

Magnesium plays a direct role in forming the hydroxyapatite crystals that give bones their density and rigidity. 

It also regulates parathyroid hormone, which controls how much calcium is released from bone into the bloodstream. When magnesium levels are low, the parathyroid can become overactive, pulling calcium out of bones even when dietary intake is sufficient.

Despite its importance, some estimates suggest that over half of adults don’t meet the recommended daily magnesium intake. Symptoms of this often include muscle cramps, joint stiffness, or poor sleep, issues that are frequently attributed to aging or stress. Thus, accurate testing is important to determine if this is a deficiency you need to address.

RBC magnesium levels can provide an accurate picture of intracellular magnesium status than standard serum tests, and help guide approaches or protocols for adjusting supplementation or diet.

Omega-3 fatty acids

Chronic, low-grade inflammation is one of the most underrecognized drivers of bone loss and joint degradation. Inflammatory cytokines stimulate osteoclast activity, accelerating the breakdown of bone tissue. In the joints, the same inflammatory processes erode cartilage and contribute to stiffness, swelling, and reduced mobility over time.

Omega-3 fatty acids—particularly EPA and DHA—help modulate these inflammatory pathways, reducing the signals that trigger excessive bone resorption and joint damage. In fact, research has shown that higher omega-3 levels are associated with greater bone mineral density and reduced markers of systemic inflammation. 

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How Welle tracks and optimizes skeletal health

While a DEXA scan from your physician can tell you where your bone density stands today, it doesn’t explain why. This is where Welle’s comprehensive bloodwork comes in, testing over 180 biomarkers to reveal the nutrient imbalances and inflammatory markers that drive bone loss long before a scan picks it up. 

Markers, such as serum 25(OH)D, osteocalcin, RBC magnesium, omega-3 index, and CRP, provide the upstream data needed to act early and act precisely. Welle uses this data to build personalized plans based on your actual levels, not population-wide recommended daily allowances that may not reflect what your body needs. 

As your markers shift, your plan shifts with it. Ongoing monitoring means your protocol evolves in real time, ensuring that the nutrients you’re taking are producing measurable results.

At the end of the day, strong bones aren’t built by one nutrient or one supplement. They’re built by a system working in sync—absorption, activation, mineralization, and inflammation control all operating together. With the right testing and a targeted plan, skeletal health becomes something you don’t just monitor, but actively strengthen, at any age.

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Sources

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2. Khazai, N., Judd, S. E., & Tangpricha, V. (2008). Calcium and vitamin D: skeletal and extraskeletal health. Current rheumatology reports, 10(2), 110–117. https://doi.org/10.1007/s11926-008-0020-y 
3. Maresz K. (2015). Proper Calcium Use: Vitamin K2 as a Promoter of Bone and Cardiovascular Health. Integrative medicine (Encinitas, Calif.), 14(1), 34–39.
4. Christakos, S., Dhawan, P., Porta, A., Mady, L. J., & Seth, T. (2011). Vitamin D and intestinal calcium absorption. Molecular and cellular endocrinology, 347(1-2), 25–29. https://doi.org/10.1016/j.mce.2011.05.038
5. Liu, L., Luo, P., Wen, P., & Xu, P. (2024). The role of magnesium in the pathogenesis of osteoporosis. Frontiers in endocrinology, 15, 1406248. https://doi.org/10.3389/fendo.2024.1406248
6. Vetter, T., & Lohse, M. J. (2002). Magnesium and the parathyroid. Current opinion in nephrology and hypertension, 11(4), 403–410. https://doi.org/10.1097/00041552-200207000-00006
7. Office of Dietary Supplements - magnesium. (n.d.-b). https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
8. Liu, Z., Cai, S., Chen, Y., Peng, Z., Jian, H., Zhang, Z., & Huang, H. (2025). The association between dietary omega-3 intake and osteoporosis: a NHANES cross-sectional study. Frontiers in nutrition, 11, 1467559. https://doi.org/10.3389/fnut.2024.1467559
9. Ozaki, Y., Morozumi, T., Watanabe, K., Toyama, T., Sasaki, H., Sato, T., Yamamoto, Y., To, M., Inaba, K., Tsukinoki, K., Hamada, N., & Minabe, M. (2020). Inhibitory effect of omega-3 fatty acids on alveolar bone resorption and osteoclast differentiation. Journal of oral science, 62(3), 298–302. https://doi.org/10.2334/josnusd.19-0267 
10. Liu, Z., Cai, S., Chen, Y., Peng, Z., Jian, H., Zhang, Z., & Huang, H. (2025). The association between dietary omega-3 intake and osteoporosis: a NHANES cross-sectional study. Frontiers in nutrition, 11, 1467559. https://doi.org/10.3389/fnut.2024.1467559