Vitamin D and COVID-19

There have recently been advances in the treatment of COVID-19. Clinical trials support intervention with steroids and antiviral drugs to shorten both the length and severity of illness. Vitamin D has also been suggested as both a prevention and treatment but as yet all positive evidence is indirect. However, the strength of the evidence has prompted several authorities to recommend Vitamin D supplementation on a population level. Vitamin D deficiency is easily treatable by supplements, which are very safe^[1].

Vitamin D is known as the sunshine vitamin being made by the action of sunlight on our skin. People living in higher latitudes tend to have lower levels of Vitamin D and increased mortality from COVID-19. In addition Vitamin D deficiency is more common in obese individuals, people with type 2 diabetes, hypertension, and most strikingly amongst ethnic minorities in Europe and North America, all of whom have higher mortality rates from COVID-19

According to the Royal Society, Vitamin D deficiency is associated with an increased risk of both respiratory viral infections and inflammatory conditions. Vitamin D has an important regulatory role in the human immune system, so a deficiency of Vitamin D is likely to cause immune dysregulation, which may reduce the first line of our defence against COVID-19^[2].

Charles Bangham, professor of immunology at Imperial College London and co-author of the Royal Society paper, said: “I started from quite a sceptical position, doubting whether vitamin D was going to play an important role in COVID-19, but I am now convinced that there is strong evidence that people who are deficient in vitamin D are more susceptible to acute respiratory tract infections^[3].”

Many countries have recommendations for use of vitamin D supplements. UK Government advice during the COVID-19 pandemic is that everyone should consider taking 10 micrograms (400iu) of vitamin D a day because they might not be getting enough from sunlight if they're indoors most of the day. Six medical societies from across the globe are also emphasizing the importance of individuals obtaining the daily recommended dose of vitamin D, especially given the impact of the COVID-19 pandemic on outdoor time. They felt the need to clarify the recommendations for clinicians. Central to the guidance is the recommendation to directly expose the skin to sunlight for 15 - 30 minutes per day, while taking care to avoid sunburn.

In Hong Kong with social distancing measures in place, particularly the closure of pools and beaches, it may be hard to achieve adequate daily sun exposure. This being the case individuals and families may wish to supplement with Vitamin D. According to Public Health England there are many brands, and formulations of vitamin D supplements that may have different recommended doses^[4]. This can make deciding which supplement to take difficult without health professional advice. If in doubt a blood test for Vitamin D status is readily available in Hong Kong and can allow your Doctor to guide your supplementation with Vitamin D.

References

1. Rhodes, J., Subramanian, S., Laird, E., Griffin, G., Kenny, R. (2020) Perspective: Vitamin D deficiency and COVID-19 severity –plausibly linked by latitude, ethnicity, impacts on cytokines,ACE2 and thrombosis. Journal of Internal Medicine. doi.org/10.1111/joim.13149

2. The Royal Society (2020) Vitamin D and COVID-19.Retrieved July 27, 2020, from https://royalsociety.org/-/media/policy/projects/set-c/set-c-vitamin-d-and-covid-19.pdf

3. Cookson, C. (2020). Vitamin D promoted as potential defence against coronavirus. Retrieved July 27, 2020, from https://www.ft.com/content/932920f9-f9ae-414a-940f-602169ee620f

4. McCall, B. (2020). Medical Societies Advise on Vitamin D in Midst of COVID-19. Medscape. Retrieved July 27, 2020 from https://www.medscape.com/viewarticle/933715

5. NICE (2020). COVID-19 rapid evidence summary: Vitamin D for COVID-19 Retrieved July 27, 2020 from https://www.nice.org.uk/advice/es28/chapter/Key-messages