Sunshine vitamin D and COVID-19: Is there a correlation?
LEIPZIG, Germany: Vitamin D, also referred to as the sunshine vitamin, is increasingly more difficult to obtain from sun exposure. The increase in the number of people working in offices today has drastically reduced access to direct sunlight. The strict confinement measures worldwide to slow down the spread of SARS-CoV-2 can only have worsened this situation. Vitamin D deficiency has been found to be associated with dental implant failure and complications, and mounting evidence is suggesting that inadequate vitamin D levels in the blood could play a major role in SARS-CoV-2 susceptibility and outcomes.
Vitamin D supports the immune system and is instrumental in development of healthy bone and muscles and strengthening of tooth enamel. Yet, according to an article published by the National Center for Biotechnology Information earlier this year, approximately one billion people worldwide have vitamin D deficiency, and 50% of the global population has vitamin D insufficiency.
A recent article published by Dental Tribune International (DTI) reported on previous studies that highlighted the impact of vitamin D deficiency on osseointegration and failure of immediate implants. Additionally, an optimal diet rich in vitamin D has been found to reduce gingivitis, and DTI has previously reported on a study that showed that vitamin D supplementation during pregnancy improved the oral health of offspring during childhood.
The role of vitamin D deficiency in SARS-CoV-2 infection
Vitamin D has been shown to have a beneficial impact in preventing infection with bacterial and viral diseases. In a recent study conducted by University Hospitals Birmingham NHS Foundation Trust in the UK, researchers analysed blood samples from 392 healthcare workers who were recruited in May 2020, testing them for the presence of SARS-CoV-2 antibodies and establishing the concentration of vitamin D in their blood.
They found that 15.6% of the participants infected with SARS-CoV-2 were deficient in vitamin D. Additionally, those who were deficient in vitamin D tended to report body ache, pain and fever, but not the respiratory symptoms associated with COVID-19, such as breathlessness or a continuous cough. The researchers noted that the majority of the workers with low-level vitamin D came from Black, Asian and minority ethnic backgrounds or were in junior doctor roles. Vitamin D levels were lower in younger participants and male participants, as well as in those with a high body mass index.
The findings also suggested an increase in the development of detectable SARS-CoV-2 antibodies in 72% of the healthcare workers with vitamin D deficiency compared with 51% without a deficiency. Given these results, the researchers concluded that lower vitamin D levels in participants could have increased their susceptibility to the virus.
“Understanding whether treating vitamin D deficiency changes COVID-19 risk could be of great importance locally, nationally and globally,”
— Dr David Meltzer, University of Chicago Medicine
“Our study has shown that there is an increased risk of COVID-19 infection in healthcare workers who are deficient in vitamin D,” said co-author Dr David Thickett, professor in respiratory medicine in the Institute of Inflammation and Ageing at the University of Birmingham in the UK, in a press release.
“Our data adds to the emerging evidence from studies in the UK and globally that individuals with severe COVID-19 are more vitamin D-deficient than those with mild disease. Finally, our results, combined with existing evidence further demonstrates the potential benefits of vitamin D supplementation in individuals at risk of vitamin D deficiency or who are shown to be deficient as a way to potentially alleviate the impact of COVID-19,” he added.
A similar study conducted at the University of Chicago Medicine in the US examined 489 patients, whose vitamin D levels had been measured within a year before being tested for SARS-CoV-2. The researchers found that patients who had untreated vitamin D deficiency, that is, less than 20 ng/ml of vitamin D in their blood, were almost twice as likely to test positive for SARS-CoV-2 compared with patients who did not suffer from vitamin D deficiency.
“Vitamin D is important to the function of the immune system and vitamin D supplements have previously been shown to lower the risk of viral respiratory tract infections,” commented lead author Dr David Meltzer, Fanny L. Pritzker Professor of Medicine at the University of Chicago Medicine, in a press release. “Our statistical analysis suggests this may be true for the COVID-19 infection.”
“Understanding whether treating Vitamin D deficiency changes COVID-19 risk could be of great importance locally, nationally and globally,” he said and added that vitamin D is cost-efficient, generally considered safe to take and can be widely scaled.
Taking vitamin D supplementation—is it necessary?
Expert in senior care pharmacy practice, Dr William Simonson from the College of Pharmacy at Oregon State University in Corvallis in the US noted in a recent article that, as SARS-CoV-2 is a new virus, the link between vitamin D and SARS-CoV-2 prevention is still highly speculative, as is the case with other treatments. However, he believes that there is “sound reasoning behind this speculation”.
Bodies such as the UK’s Scientific Advisory Committee on Nutrition, National Institute for Health and Care Excellence, and Royal Society have recently published reports in which they advised adhering to the current recommended vitamin D daily intake for overall health and as a possible precaution against the virus. To maintain the optimal level of vitamin D in the blood, the National Health Service advises taking a 10 µg supplement of the vitamin a day.
The UK study, titled “Vitamin D status and seroconversion for COVID-19 in UK healthcare workers who isolated for COVID-19 like symptoms during the 2020 pandemic”, was published online on 6 October 2020 on medRxiv.
The US study, titled “Association of vitamin D status and other clinical characteristics with COVID-19 test results”, was published online on 3 September 2020 in JAMA Network Open.