With the novel coronavirus sweeping around the world, everyone is finding ways to protect themselves and their loved ones. Respiratory illnesses are often reported during cold environment and “catching a cold” during warm, sunny weather is counter-intuitive. Although the relationship is still not fully understood, the key factor that influence the susceptibility to these diseases could be the level of vitamin D, an important hormone that plays an essential role in multiple processes in the cell, which is produced in the skin following sunlight exposure.
Forms of Vitamin D
There are two major forms of vitamin D, vitamin D2 and D3. Vitamin D2 is ergocalciferol and comes from plant-based sources. Whilst vitamin D3 is known as cholecalciferol, the human form of vitamin D, and was made in large quantities in the skin when sunlight strikes bare skin. It can also be ingested from animal sources. Both vitamin D2 and D3 have to be metabolized in the liver to produce 25-hydroxyvitamin D3 (calcifediol) and again in the kidney to produce 1,25-dihydroxyvitamin D3 (calcitriol).
Vitamin D as preventive agent for Covid-19
Interest in the potential role for vitamin D as a preventive or therapeutic agent for Covid-19 increased after there have been studies conducted looking at correlations between vitamin D and Covid-19. One of the retrospective epidemiological paper that has caught the hype in the news and on social media was on a small group of people who were hospitalized with Covid-19. The authors have found that people who had lower vitamin D levels were more likely to experience consequences of Covid-19, such as low blood oxygen and death. Whilst another retrospective study found that people with vitamin D deficiency was 1.77 times greater to be tested positive for Covid-19 than patients with sufficient vitamin D status. Some studies found that Covid-19 deaths tend to be higher in countries farther away from the equator, where people with deficient in vitamin D were reported due to the reduced amount of sunlight, especially during winter. These data suggested that having enough vitamin D not only reduced the risk of getting Covid-19 and the adverse outcomes of the disease.
How vitamin D could help fight against respiratory illnesses such as Covid-19? Vitamin D metabolites have long been known to support innate antiviral effector mechanisms, including induction of antimicrobial peptides and autophagy. Evidences on the inhibitory effect of the active vitamin D metabolite 1,25-dihydroxyvitamin D in human nasal epithelial cells infected with SARS-CoV-2 have been reported. Vitamin D also reported to downregulate ACE2 receptor, which is a key in SARS-CoV-2 entry into the host cells.
Should you take vitamin D supplements?
“If you are deficient in vitamin D, that does have an impact on your susceptibility to infection. So, I would not mind recommending, and I do it myself taking vitamin D supplements.”
Dr. Anthony Fauci (Director of the National Institute of Allergy and Infectious Diseases)
Vitamin D deficiency is one of the most common nutritional deficiencies in the world, and supplementation is a safe intervention. Consumption of Vitamin D are highly recommended to older or elderly people as they have lower levels of vitamin D which might increased adiposity, reduced rates of vitamin D synthesis in the skin and absorption of vitamin D in the gut. Recent study from large meta-analysis has shown that no adverse effects on the consumption of vitamin D by healthy people. “If you are deficient in vitamin D, that does have an impact on your susceptibility to infection. So, I would not mind recommending, and I do it myself taking vitamin D supplements,” mentioned by Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. As the global conversation around Covid-19 continues to evolve, Vitamin D remains important to maintain overall health and helping the body respond to outside viruses and infections.
Article Written by : Dr Alicia