COVID-19 and Vitamin D – an overview (updated 22.10.2020)
As the number of people in Europe infected with the novel SARS-CoV-2 increases rapidly again, there is still no vaccine or real cure available. Despite a better understanding of the virus and lower mortality rates, there are still many unknowns in terms of immunity or long-term consequences for example. On the other hand, there is a growing evidence that vitamin D might play a crucial role in preventing and fighting against the virus.
During the summer, many preliminary studies were published that suggest a link between vitamin D deficiency and COVID-19 severity as well as mortality. Recently, two studies have added to the growing evidence that vitamin D can support the immune system in its’ fight against the virus. Researchers from a hospital in Cordoba, Spain found that vitamin D given as part of a treatment can reduce severity of COVID-19 infection.1 The other publication from a team of the university of Chicago concluded that patients with insufficient vitamin D levels had double the risk to contract the disease.2
That means that vitamin D strengthens the immune system and therefore not only acts in a protective way against COVID-19 by help reducing the entry of SARS-CoV-2 into cells but also prevents the hyper-inflammatory response that is so characteristic of a severe infection.
Vitamin D allows immune cells and epithelial cells (such as those in the lungs) to increase their production of antimicrobial peptides and reinforce the physical barrier for better response against infections. Study have shown that this is especially true for the airway epithelial cells in response to a viral infection.3
Next to these immunoregulatory functions, vitamin D plays an essential role in human health, especially in bone health by preventing osteoporosis, but also in the prevention of a number of cancers such as prostate, pancreatic and breast cancer as well as autoimmune diseases like multiple sclerosis and diabetes.4
The primary source of this essential hormone (and other components needed for good health) is UV radiation from moderate sun exposure or artificial tanning devices. The solar ultraviolet radiation that is reaching the surface of the Earth varies with latitude, time of day and season. Around 95% is the longer wavelengths of UVA, with the remaining 5% being UVB. Only the absorption of UVB light absorbed by the skin starts a chemical process in which vitamin D is produced. “The best way to obtain a given dose of vitamin D with minimal carcinogenic risk is through a non-burning exposure in the middle of the day, rather than in the afternoon or morning”, as the authors of another study5 conclude.
Not only during the winter months when the amount of UVB in the sunlight is not enough to maintain sufficient serum vitamin D levels, supplementation and especially artificial tanning devices can be valid alternatives.6 In fact, most indoor tanning equipment emits a similar UVA:UVB ratio as the natural sun with a maximum intensity equaling the midday sun in the Mediterranean. Further, there are constant conditions controlled by trained and certified operators who are also able to provide valuable advice to the consumers following professional standards.
The European Sunlight Association (ESA) is promoting safe, controlled and informed use of sunbeds in compliance with EU legislation. To ensure consumer safety, ESA is working hand in hand with the EU and Member State national authorities towards the implementation and enforcement of mandatory standards across Europe.
Find further information in this COVID-19 factsheet here
1Castillo et al. (2020). Effect of Calcifediol Treatment and best Available Therapy versus best Available Therapy on Intensive Care Unit Admission and Mortality Among Patients Hospitalized for COVID-19: A Pilot Randomized Clinical study. Journal of Steroid Biochemistry and Molecular Biology.
2Meltzer et al. (2020). Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results. JAMA Network Open.
3Martineau et al. (2017). Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. British Medical Journal.
4Hoel et al. (2018). Sun Exposure Public Health Directives. International Journal of Environmental Research and Public Health. International journal of environmental research and public health.
5Grigalavicius et al. (2015). Daily, seasonal, and latitudinal variations in solar ultraviolet A and B radiation in relation to vitamin D production and risk for skin cancer. International Journal of Dermatology.
6de Gruil and Pavel. (2012). The effects of a mid-winter 8-week course of sub-sunburn sunbed exposures on tanning, Vitamin D status and colds. Photochemical & Photobiological Sciences.