Marc Darrow MD, JD 

Vitamin D can be an important supplement in supporting various types of knee osteoarthritis treatments. Research as outlined below suggests that vitamin D supplementation can help alleviate pain and symptoms related to degenerative knee disease. What I hope to achieve in this article is that if you have a realistic expectation of what vitamin D can actually help you with and what it can’t, you will probably have good results from vitamin D supplementation.

Short-term vitamin D supplementation should not be expected to reverse years of accelerated degenerative damage in the knee

When it comes to vitamins and vitamin supplementation in promoting and supporting healing in osteoarthritis, there is also always a degree of inconsistency and controversy in the findings as to how much vitamin D supplementation can help patients with knee osteoarthritis. One of the problems may be an over expectation of what vitamin D can actual do. In the first study study below, researchers offer the view that short-term vitamin D supplementation should not be expected to reverse years of accelerated degenerative damage in the knee as a stand alone knee pain treatment recommendation. Vitamin D may help relieve pain from degenerative knee disease and support and maintain cartilage health and help with mobility, but as we suggest and recommend to our patients, vitamin D is best seen as a supportive care supplement. Not as a primary remedy for knee pain.

The research

A recent July 2019 study in the journal American College of Rheumatology open (1) suggests why these inconsistent and controversial findings may exist. Much of it has to do with measuring the success of vitamin D as a stand alone treatment in the short-term. “The results of a few studies showed a preventive potential for vitamin D in knee osteoarthritis but the results of studies addressing the association and effect of vitamin D supplementation for pain, function, quality of life, radiographic disease, and progression are inconsistent. The results of a few studies showed a preventive potential for vitamin D in knee osteoarthritis, but most of the randomized clinical trials that assessed the therapeutic efficacy of vitamin D supplementation in knee osteoarthritis found no clear therapeutic effect, with the exception of one study that found a small but significant effect of vitamin D on pain and knee function. Nonetheless, the results of a few longitudinal studies as well as systematic reviews are promising and thus encourage further studies. Inconsistent results on the effect of vitamin D on knee osteoarthritis may be attributed to factors such as severity of knee osteoarthritis , baseline level of serum vitamin D, duration of treatment, and vitamin D dosages.

It should be noted that osteoarthritis is a chronic condition and that osteoarticular changes occur several years after exposure to risk factors. Therefore, recovery of these structural changes requires long‐term treatment. Thus, short‐term clinical trials are not expected to be associated with a detectable improvement in structural abnormalities by using radiography or MRI. On the other hand, lack of a correlation between clinical symptoms and structural changes in knee osteoarthritis makes it difficult to show structural recovery in subjects with clinical improvement.”

Researchers look at patients with knee cartilage loss, bone spurs who take vitamin D

In a July 2019 study, (2) from the University of California, San Francisco and the University of California, Davis, researchers  examined a knee osteoarthritis patient group. Of these patients 98% had cartilage loss, 92% had osteophytes (bone spurs). Supplementation with vitamin D over four years was associated with significantly less progression of knee joint abnormalities including the bone spurs..

Vitamin D’s role as anti-inflammatory

A December 2019 study in the journal Biochemistry and cell biology (3) offered these insights into the workings of how vitamin D may help people with chronic knee pain from degenerative wear and tear.

  • “Vitamin D is essential for bone function in human body. (the researchers) hypothesized that active Vitamin D may play key functions in osteoarthritis treatment. Low level of serum 25-hydroxyvitamin D (25(OH)D) was found in osteoarthritis patients, and (low levels of) serum Vitamin D level might be supportive (of a) osteoarthritis diagnosis.”

In this animal study the research team looked at mice  and hypothesized that active Vitamin D might activate chondrocyte autophagy to reduce osteoarthritis inflammation. You will certainly recognize the benefit of reducing inflammation, but what about activating chondrocyte autophagy, what does that mean?

Autophagy is the body’s way of cleaning out dead tissue. It is part of the inflammatory process. In chronic inflammation, there is a vicious cycle. Cartilage cells continue to die and need to be cleaned up. Inflammation cleans them up, however, chronic inflammation kills healthy cartilage cells  as well. As cartilage cell death piles up the immune system needs to create more inflammation to get rid of accumulating dead cartilage. Eventually the you will have no cartilage. This is one way to get to bone on bone. Runaway Autophagy, i.e, inflammation.

In this study, the research team suggested that vitamin D prevents the vicious cycle by autocorrecting messages in the inflammatory pathways that instruct the immune system to stop killing good cartilage cells by turning down the inflammation and regulating the inflammatory cycle.

Vitamin D can help prevent infections following knee replacement

Vitamin D does have a place in helping a patient with knee osteoarthritis. It also has a place in “conventional” medicine. In December 2019 (4) researchers at the Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA wrote that vitamin D supplementation may reduce incidence of joint infection and the need for a secondary or revision knee replacement surgery.

An earlier 2017 study (5) also suggested that vitamin D deficiency patients had significant longer hospital stays and significant worse functional outcomes in the short and the long-term following knee replacement surgery.

Vitamin D can help

Vitamin D supplementation can help many people with joint / knee pain. How much can it help? That is the debate within the medical community.


Do you have questions? Ask Dr. Darrow about your knee pain



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1 Heidari B, Babaei M. Therapeutic and Preventive Potential of Vitamin D Supplementation in Knee Osteoarthritis. ACR Open Rheumatol. 2019 Jul 3;1(5):318-326. doi: 10.1002/acr2.1042. PMID: 31777808; PMCID: PMC6857993.
2 Joseph GB, McCulloch CE, Nevitt MC, et al. Associations between Vitamin C and D Intake and Cartilage Composition and Knee Joint Morphology over 4 years: Data from the Osteoarthritis Initiative [published online ahead of print, 2019 Jul 8]. Arthritis Care Res (Hoboken). 2019;10.1002/acr.24021. doi:10.1002/acr.24021
3 Kong C, Wang C, Shi Y, Yan L, Xu J, Qi W. Active Vitamin D activates chondrocyte autophagy to reduce osteoarthritis via mediating the AMPK/mTOR signaling pathway. Biochemistry and Cell Biology. 2019 Dec 9(ja).
4. Arshi A, Shieh A, Adams JS, Bernthal NM, Zeegen EN, Sassoon AA. Preoperative Vitamin D Repletion in Total Knee Arthroplasty: A Cost-Effectiveness Model [published online ahead of print, 2019 Dec 27]. J Arthroplasty. 2019;S0883-5403(19)31186-6. doi:10.1016/j.arth.2019.12.037
5 Jansen J, Tahmassebi J, Haddad FS. Vitamin D Deficiency Is Associated With Longer Hospital Stay And Lower Functional outcome After Total Knee ArthroplastyActa Orthop Belg. 2017;83(4):664–670. 1345