The Statement
A Facebook post claims vitamin D supplements can prevent a COVID-19 infection and reduce severity.
The lengthy post features two images, one which shows a container of yellow pills and another featuring a table with the recommended sun exposure for adequate vitamin D synthesis in most Australian major cities.
The text in the first image reads, “A vitamin D deficiency is a major risk factor to all respiratory infections – colds, flu and the coronavirus. Supplementing with vitamin D can prevent COVID-19 infection and reduce severity”.
The post goes to make the claim, “therapeutic doses require a minimum of 3000-5000IU per day for adults for at least 6 weeks (Diamond et al., 2005), in order to increase your levels and get health benefits.”
The August 14 post, on a page for a business called Ross Walter Nutritionist & Naturopath, has attracted more than 170 shares and more than 20,000 views.
The Analysis
Can vitamin D supplements prevent a COVID-19 infection and reduce its severity? The Facebook post’s claim is not supported by conclusive medical evidence, nor by experts in pharmacology, physiology and infectious diseases contacted by AAP FactCheck.
Vitamin D is produced in some foods, supplements and through ultraviolet light from the sun on the skin. It also promotes calcium absorption in the body which is needed for bone growth and plays a significant role in the human immune system promoting immune cell production.
The claim that vitamin D supplementation can treat or prevent COVID-19 infections has been the subject of several studies during the COVID-19 pandemic with differing findings.
A review into the effect of vitamin D as a treatment or prevention for COVID-19 by the University of Oxford’s Centre for Evidence-Based Medicine found “no clinical evidence that vitamin D supplements are beneficial in preventing or treating COVID-19”.
The British Medical Journal (BMJ) released a report in April 2020 summarising evidence of the associations between vitamin D, influenza, upper respiratory tract infections and immune health to provide “a balanced scientific view on vitamin D and SARS-CoV-2 virus/COVID-19 disease”.
The report concluded: “We recommend appropriate vitamin D randomised controlled trials to evaluate the effects of vitamin D supplementation on COVID-19 infections. Until there is more robust scientific evidence for vitamin D, we strongly caution against the use of high vitamin D supplementation”.
Dr Ian Musgrave, a lecturer in pharmacology at the University of Adelaide, told AAP FactCheck the Facebook post was “incredibly misleading” and that there is no evidence that vitamin D is associated with COVID-19 infection.
“There’s been a number of suggestive studies, but they have been of very poor quality, and a recent review by the National Institute of Clinical Excellence in the UK concluded that it was age and health status, not vitamin D levels, that were associated with COVID-19 infections,” he said.
Rebecca Mason, a professor of endocrine physiology from the University of Sydney, who told AAP FactCheck in an email that it is not known whether vitamin D can prevent or reduce the severity of COVID-19 infections.
“There are several trials underway at the moment worldwide to test this proposal. The evidence provides some support for doing the trials. Whether this all is supported when the trial results come out remains to be seen,” she said.
Dr Gaetan Burgio, a geneticist and infections researcher at the Australian National University, told AAP FactCheck in an email there is no convincing evidence to date that vitamin D would prevent COVID-19 infection and reduce severity.
“Over 30 ongoing clinical trials are exploring this possibility and will provide some additional insights on the efficacy of vitamin D supplementation for COVID-19 within weeks,” he said.
Previous studies, including one from the BMJ in 2017, have supported the claim that vitamin D plays a role in protecting people from contracting acute respiratory tract infections.
Dr Burgio said though there is evidence that vitamin D supplementation can protect against acute respiratory infection, there isn’t enough to implement a vitamin D administration strategy to a large population.
“Dose amounts and intervals to provide a protective effect to a large population are still unknown and there is no evidence that Vitamin D administration, once vitamin D levels are corrected, would provide a protective effect against acute respiratory infections,” he said.
The post also claimed therapeutic doses require a minimum of 3000-5000IU per day for adults for at least six weeks in order to increase vitamin D levels and get health benefits.
The BMJ report from April 2020 cautioned against a high dosage of vitamin D supplements.
“Until there is more robust scientific evidence for vitamin D, we strongly caution against the use of high vitamin D supplementation (greater than the upper limit of 4000 IU/day (100 micrograms per day). Rather, we strongly endorse avoidance of vitamin D deficiency in the population,” it said.
Dr Musgrave told AAP FactCheck there is “no evidence whatsoever” to support the post’s recommendation of taking 3000-5000IU of vitamin D every day for six weeks as a preventative against COVID-19.
“Consistently high levels of supplementation have not shown to have that level of benefit, and they have their own risks,” he said.
Similar claims about vitamin D supplements as a preventative for COVID-19 have been previously debunked here, here and here.
The Verdict
Based on the evidence, AAP FactCheck found the claims in the Facebook post to be false. There is currently no conclusive medical evidence that vitamin D can prevent COVID-19 or reduce its severity. There is also no evidence to support a recommendation of taking up to 5000IU of vitamin D supplements as a preventative for COVID-19.
False – The primary claim of the content is factually inaccurate.
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