Craig Payne

University lecturer, runner, researcher, skeptic, woo basher, clinician

Nov. 20, 2020
Published on:
5 min read
Vitamin D and the Foot

I have been doing my weekly update on research and views for a few years now and you start to see patterns in the research and the literature. One that really stood out like a sore thumb was vitamin D. At one stage a year or so ago, I was commenting at least weekly on something to do with vitamin D and the foot. I even got feedback that I was some sort of vitamin D junkie (I’m not). More lately its probably once a month or so, but that is still a lot compared with other topics. Its hard not to miss how much research has been regularly and recently added to the threads on Podiatry Arena on vitamin D and the diabetic foot and the thread on vitamin D and foot and ankle injuries. With that sheer volume of content and research one can not help but think that it might be important and relevant.

What is obvious from all that research is the frequent correlation between lower levels or a deficiency of vitamin D and wide range of foot and ankle problems (from diabetic foot ulcers to stress fractures to muscle strains to the outcome of trauma etc). There are strong correlations between low vitamin D and a whole range of general medical conditions. Even more recent is all the research showing strong correlations between getting COVID-19, the seriousness of COVID-19, the outcomes of COVID-19 and vitamin D.

It is from there that there is a divergence between the science and the pseudoscience. The research has clearly and strongly demonstrated the correlation with low vitamin D and a whole lot of problems. We all know that correlation is not causation, but those promoting pseudoscience or selling vitamins do not get or understand the difference. That science is generally not so strong on the causation which has not stopped the cranks promoting the pseudoscience. There is generally very little evidence that prospectively links vitamin D to a higher risk of problems. There is also limited research showing that taking vitamin D fixes the problems that a deficiency is correlated to. That general lack of prospective evidence does not mean that vitamin D is not important, it just means that we need to be cautious about claims made for it and that context needs to be acknowledged.

Of course, generally, if someone is deficient in vitamin D, they probably should be taking supplements to get that up to normal. What should not be done is promoting vitamin D as a treatment if vitamin D levels are normal. Take any more than the required amount and the body just tries to excrete it. Vitamin D toxicity from over-supplementation (rather than an overdose of sun) is a thing and carries risks.

The COVID-19 case is an interesting one to observe. I have seen vitamin D supplements advocated to help prevent catching the coronavirus, probably from those selling vitamin D. There is no evidence that will work, despite the high correlation between COVID-19 and the vitamin D deficiency. Of course those sick with COVID-19 and are deficient should be given supplements as it just makes sense. The line has to be drawn at claiming vitamin D as a treatment for it, which certainly has not stopped the cranks with no experience in treating COVID-19 from claiming. While, I have doubts that this is the case, but it could well be that COVID-19 increases the demand for vitamin D, so the infection causes the deficiency rather than the other way around. These types of conclusions or hypotheses can not be made or excluded based on the current state of the science.

This area also attracts more than its fair share of clueless cranks, especially those who talk about vitamins boosting the immune system. If you hear anyone talking about that, stop listening or (preferably) call them out for their dribble. The last thing I want to do is boost my immune system.

Yes, vitamin D is important for foot and ankle problems; and yes, getting out in the sun and taking supplements is important. Just stop listening to the cranks. The buzz about vitamin D is overblown.

Disclaimer: I take a low dose of vitamin D as I have one of the conditions that correlates to low levels of vitamin D.

The issue is important enough that we have an upcoming episode of PodChatLive on it.


The Podiatry Practice Business Solution: Everything You Need to Know to Flourish in Your Podiatry Business
Podiatry Axial/Sesamoid Weight Bearing Sponge (Closed Cell)
Ultrasound of the Foot and Ankle
Mann’s Surgery of the Foot and Ankle, 2-Volume Set: Expert Consult: Online and Print (Coughlin, Surgery of the Foot and Ankle 2v Set)
Coding Companion for Podiatry 2020
McGlamry's Comprehensive Textbook of Foot and Ankle Surgery, Volume 1 and Volume 2
Sarrafian's Anatomy of the Foot and Ankle: Descriptive, Topographic, Functional
Simple Steps to Foot Pain Relief: The New Science of Healthy Feet
Reconstructive Foot and Ankle Surgery: Management of Complications
Watkins' Manual of Foot and Ankle Medicine and Surgery

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