Vitamin D and COVID-19

For the past two years, Coronavirus Disease-2019 (COVID-19) is a rapidly developing pandemic disease due to the infection by Severe Acute Respiratory Syndrome Corona-Virus-2 (SARS-CoV-2) and so far, 5,554,979 people have died so far from the coronavirus COVID-19 worldwide. The virus has high transmissibility, mainly through droplets and breath or by direct contact. The clinical symptoms of the disease range from completely asymptomatic forms up to severe cases requiring admission to the Intensive Care Unit (ICU) with Acute Respiratory Distress Syndrome (ARDS) often associated with multi-organ failure. To date, there is little information available for effective treatment regarding the factors that can affect vulnerability to infection and its severity.

Even though vaccination has proved to be effective, coronavirus disease 2019 (COVID-19) with the new Omicron variant still poses a continuing threat to public health. Therefore, in addition to vaccination, the use of supplements to support the immune system may be important. The medical community has conducted studies and there is evidence that vitamin D may enhance the immune functions in human cells and reduce the spread of some viruses. Vitamin D is a fat-soluble vitamin and is important for healthy bones, teeth, and muscles. It helps to regulate blood sugar, the heart, blood vessels, airways, and the lungs. It also boosts our immune system (which is our body’s first line of defense against infection and disease). Furthermore, this vitamin contains both anti-inflammatory and immunoregulatory properties and is crucial for the activation of immune system defenses. These are areas affected by COVID‐19, so giving vitamin D to patients with COVID‐19 is helping them to recover more quickly or helping the disease to become less severe.

Low levels of vitamin D have been associated with increased susceptibility to infection, disease, and immune-related disorders. There is increasing scientific interest in the possible association between hypovitaminosis D (low level of Vitamin D) and the risk of SARS-CoV-2 infection severity or mortality. The data has been backed up especially in the first phase of the pandemic, when the SARS-CoV-2 infection was more frequent and disturbing, particularly regarding mortality rate, in the Southern European countries (e.g., Italy and Spain) in which hypovitaminosis D was most common. The elderly, and exceptionally those living in care homes, were those who have paid the most serious consequences of the disease. As known, they also represent a percentage of the population in which hypovitaminosis D is considered endemic. Similar considerations have been made regarding individuals who were obese or who had high levels of melanin.

COVID-19 mainly attacks the respiratory tract, and the data is supporting a significant effect of vitamin D in preventing respiratory tract infections. Another study published in 2017 (before the pandemic) analyzed over 11,300 patients from 25 randomized studies and established the protective effect of vitamin supplementation D on respiratory tract infections. The effect was not only statistically important but essentially was also clinically proven to be related.

In the early days of the pandemic, Dr. Roger Seheult, one of the physicians who worked on the frontline of the Covid-19, provided coverage and perspectives in an environment almost defined by information inadequacy. Dr. Seheult is quadruple board-certified in Internal Medicine, Pulmonary Diseases, Critical Care Medicine, and Sleep Medicine through the American Board of Internal Medicine. Dr. Sehult has published several articles and shared his insights through experiences treating critical patients of COVID-19. The educator has described the stages of the disease and how these stages not only correlate to the patient’s immune response but also direct the type of treatment every patient requires. Dr. Seheult describes some interesting associations between COVID-19 risks, outcomes, and vitamin D status. Dr. Seheult says, “It activates the innate immune system, which elicits an early antiviral response. The convergence of factors that increase the risk for COVID-19 severity also increases the risk for vitamin D deficiency, as seen in the surprising degree of overlap between COVID-19 positivity and groups most affected by vitamin D deficiency.” Moreover, he explains that in a study of over 190,000 people who had SARS-CoV-2, low 25-hydroxyvitamin D levels were detected despite race/ethnicity, age, and sex. In that study, lower 25-hydroxyvitamin D levels correlated with higher COVID-19 mortality risk.
Promising new data from another study indicates that active forms of vitamin D can prohibit the reproduction and inflation of COVID-19. The study’s findings also suggest lumisterol, a substance produced by a chemical reaction in the body using light, works to block COVID-19. Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, suggested in September 2020 that vitamin D could help fight COVID-19. He also estimated that 40% of the U.S. population is vitamin D deficient. Scientists in this new study were able to prove that vitamin D and lumisterol derivatives “act on multiple targets, suggesting that they may be effective against original and mutant strains of SARS-CoV-2.”

Other benefits of vitamin D cited by researchers include its low cost and easy access. Compared to other marketized products that are selling now because they offer high immunity, a simple, natural vitamin supplement with abundant health benefits (especially now, although there are many issues that can be solved with it and that can be born when in absence of it) can be found with much more accessibility and affordability.

Deficiency of Vitamin D has also been linked to other diseases such as autoimmune diseases including multiple sclerosis (MS), rheumatoid arthritis (RA), diabetes mellitus (DM), inflammatory bowel disease, and systemic lupus erythematosus (SLE). There is also data linking a decrease in utero exposure with vitamin D deficiency and can cause islet cell autoimmunity (IA). According to a study published by the Natural Library of Medicine, maternal intake of vitamin D via food was significantly associated with a decreased risk of IA appearance in offspring, independent genotype, family history of type 1 diabetes, presence of gestational diabetes mellitus, and ethnicity. Vitamin D intake through supplements, omega-3 fatty acids, and omega-6 fatty acids during pregnancy were not associated with the appearance of IA in offspring.
Vitamin D has many unknown but important/essential functions to our bodies beyond those of calcium and bone homeostasis. More studies and clinical trials are planned to test the efficacy of vitamin D as an antiviral therapeutic for COVID-19 in humans.