A new study has added to a growing body of evidence that vitamin D has a protective effect against Covid-19 in treating the disease and reducing the risk of death for patients.
In a new study published in the journal PLOS ONE, researchers from Boston University's School of Medicine looked at blood samples from 235 patients admitted to hospital with Covid-19. The patients and their outcomes, treatments, and symptoms were tracked, including the severity of their infections, whether they became hypoxic (had a deficiency of oxygen), and whether they survived the illness.
Having sufficient levels of vitamin D appeared to have a protective effect on patients. Those with a blood level of 25-hydroxyvitamin D (a prehormone produced in the liver that doctors use to determine vitamin D levels) of at least 30 ng/mL had a significantly reduced chance of becoming unconscious, hypoxic, or dying. Their blood also indicated lower levels of C-reactive proteins (an inflammatory marker) and higher levels of the immune cell lymphocytes.
In patients who were older than 40, they found that patients who were vitamin D sufficient were 51.5 percent less likely to die of the disease, compared to those who were deficient.
“This study provides direct evidence that vitamin D sufficiency can reduce the complications, including the cytokine storm (release of too many proteins into the blood too quickly) and ultimately death from COVID-19,” corresponding author Dr Michael F. Holick said in a statement.
“Because vitamin D deficiency and insufficiency is so widespread in children and adults in the United States and worldwide, especially in the winter months, it is prudent for everyone to take a vitamin D supplement to reduce risk of being infected and having complications from COVID-19.”
The good news is vitamin D is created in our bodies when we expose our skin to sunlight. In spring and summer, people are generally able to get the amount they need from exposure to the Sun. People with darker skin tones will need to spend longer in the Sun than those with paler skin in order to get sufficient levels of the vitamin. The difference in vitamin D levels could partly explain why African Americans have been hit disproportionately hard by the illness, though other factors such as socio-economics, disparities in access to health care, and being employed in frontline work that cannot be done from home likely play a large role too.
In a separate study, Horlick and team found that being vitamin D sufficient can reduce the risk of catching Covid-19 by 54 percent. He believes that it is protective against other upper respiratory tract illnesses such as influenza.
“There is great concern that the combination of influenza infection and a coronal viral infection could substantially increase hospitalizations and death due to complications from these viral infections," Horlick said.
Recent studies have found that risk of death more than doubled in patients who also had seasonal flu (influenza), so protection against both illnesses could seriously help in the coming months.
The vitamin can also be found in foods including oily fish, red meat and eggs, as well as being added to infant formula in some countries, and is widely available as a low-cost supplement.