Previous studies have also shown that certain compounds may provide protective effects against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has now infected more than 33.27 million people worldwide and claimed the lives of over one million people.
It is thought that vitamin D may offer a protective effect against SARS-CoV-2. Vitamin D interacting with its receptor (VDR) in immune cells, modulates the innate and acquired immune systems in response to the invasion of bacterial and viral pathogens. It also acts as a modulator of the renin-angiotensin pathway and down-regulates angiotensin-converting enzyme 2 (ACE2), which acts as the receptor for the SARS-CoV-2 virus and allowing it to infect the cells. Therefore, vitamin D might help treat COVID-19 by preventing the cytokine storm and subsequent acute respiratory distress syndrome (ARDS), a common cause of mortality in the disease.
Now, a new study adds to the string of evidence showing the promising effect of vitamin D in the battle against COVID-19.
A team of researchers at Boston University School of Medicine has found that patients hospitalized due to COVID-19 had a lesser risk of adverse clinical outcomes if they had sufficient vitamin D levels. The study provides direct evidence that vitamin D sufficiency reduces the complications, including the cytokine storm and death from COVID-19.
Published in the journal PLOS ONE, the study investigates the link between serum 25-hydroxyvitamin D levels and its effect on adverse clinical outcomes and parameters of immune function and mortality due to COVID-19.
Measuring vitamin D levels
To arrive at the study findings, the team gathered hospital data of 235 patients with COVID-19. The team collected blood samples to measure vitamin D status from the patients who were admitted to the hospital. From there, the researchers followed these patients to determine their clinical outcomes, including becoming unconscious, clinical severity of the infection, having difficulty of breathing and hypoxia, or the lack of oxygen levels in the body, and death.
Further, the team measured the blood samples for an inflammatory marker, called C-reactive protein, and for the levels of lymphocytes. All these parameters were collected, compared, and analyzed, both in the group of patients who had sufficient vitamin D levels and those who do not.
What the team found
Based on the U.S. Centers for Disease Control and Prevention (CDC) criteria, 74 percent of the study participants had severe COVID-19 infection, and about 32.98 percent were vitamin D sufficient. The team adjusted for confounding factors, and they found that there is a direct link between vitamin D sufficiency and the reduction of clinical severity and death, serum levels of C-reactive protein (CRP), an inflammatory marker, and the increase in lymphocyte percentage.
The study findings show that only 9.7 percent of patients of more than 40 years old, who were vitamin D sufficient, died due to COVID-19. In comparison, 20 percent of patients with a 25-hydroxyvitamin D level of less than 30 ng/ml.
“The significant reduction in serum CRP, an inflammatory marker, along with increased lymphocytes percentage suggest that vitamin D sufficiency also may help modulate the immune response possibly by reducing risk for cytokine storm in response to this viral infection,” the team wrote in the paper.
Hence, the team recommended that improving vitamin D status among the public, especially for hospitalized patients due to the coronavirus, can help reduce the severity and even death that are tied to the ravaging global health crisis.
The team also believes that being vitamin D sufficient can help fight consequences from contracting the illness, not only from the coronavirus but also other viruses that cause upper respiratory tract illness such as influenza.
Aside from that, the team said the study provides a cost-effective and straightforward means to improve a person’s ability to ward off infection from SARS-CoV-2 and reduce adverse clinical outcomes.
“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,” Dr. Michael F. Holick, professor of medicine, physiology, and biophysics and molecular medicine at Boston University School of Medicine, said.
Though the results are promising, the team said that further research is needed, particularly to know the optimum level of vitamin D to help reduce the risk of severe COVID-19.