Is vitamin D a shield against coronavirus? Researchers study Covid-19 connection

A study published in The Lancet has found a link between vitamin D and Covid-19. The study suggests vitamin D that is made by human skin under exposure to the sun can help fight Covid-19 better.

If you have been following Covid-19 related developments closely, you might have heard about cytokine storm. It is a medical complication found in Covid-19 patients, drawing commonality with SARS and MERS - all three diseases caused by coronavirus.

In simple words, cytokine storm is an overreaction of the immune system, whose job is to fight off infections. In a research published earlier this month, cytokine storm was found to be the most common cause of death in Covid-19 patients.

According to another research, conducted at the Howard Hughes Medical Institute, an American non-profit medical research organisation, preventing cytokine storm may ease severe Covid-19 symptoms.

Vitamin D has a role in preventing this cytokine storm. Vitamin D is a fat soluble vitamin which modulates the white blood cells, the principal immunity warriors in the body.

A lower level of Vitamin D in a Covid-19 patient can seriously impact modulation of the immune response of the white blood cells. An overreaction of white blood cells leads to excessive release of inflammatory cytokines into blood causing the fatal complications.

Now, a study published in The Lancet suggests that differing mortality rate of Covid-19 in different countries could be linked to "relative vitamin D status of populations".

The study says, "A growing body of circumstantial evidence now also specifically links outcomes of Covid-19 and vitamin D status In a cross-sectional analysis across Europe, Covid-19 mortality was significantly associated with vitamin D status in different populations."

According to the researchers, the role of vitamin D in the response to Covid-19 infection could be two-fold. First, vitamin D supports production of anti-microbial peptides in the respiratory epithelium, ensuring coronavirus infection leads to milder form of Covid-19, they said.

Second, vitamin D might help to reduce the inflammatory response to infection with SARS-CoV-2. Further, SARS-CoV-2 down-regulates ACE2 - a protein by hooking to it for entering human cell, vitamin D promotes its expression, thus countering infective move made by novel coronavirus.

Fresh research on Covid-19 and its link with vitamin D becomes all the more crucial for India as it is one of the countries where general population has been found to be deficient in vitamin D.

This study found that "the prevalence of Vitamin D deficiency ranged from 40 per cent to 99 per cent, with most of the studies reporting a prevalence of 80 per cent-90 per cent".

About 90 per cent of the required vitamin D is synthesized in the skin under exposure to the sun. However, due to coronavirus lockdown even those with sufficient vitamin D prevalence are at risk of turning deficient in the key vitamin.

This could be the reason why Britain has recommended vitamin D supplements to its population through this summer and autumn during which coronavirus is likely to be active.

The Lancet study, however, does not say vitamin D alone can prevent Covid-19, against which social distancing, washing hands and wearing mask remain the primary weapon. Vitamin D can still be an additional protective shield against coronavirus.