The effects of vitamin D on respiratory illnesses: a prospective natural treatment for COVID-19

Background: In the midst of COVID-19, healthcare specialists and researchers worldwide have been actively investigating treatments for this new disease. As of July 3rd, 2020, there have been a total of 11,048,509 confirmed cases in more than 188 countries and regions with more and more cases being identified every day. Though there have been a couple of medications given EUA status by the FDA such as chloroquine and hydroxychloroquine, remdesivir, and Fresenius Propoven, some of these treatments have been found to carry substantial health risks. Chloroquine and hydroxychloroquine, for example, were found to cause abnormal heart rhythms and facilitated higher rates of death among patients in clinical trials. For this reason, a more natural option such as vitamin D has the potential to be safer and more effective in the treatment of SARS-CoV-2 symptoms.Objective: In this study, I investigate the benefits of vitamin D supplementation as shown in previous clinical trials involving respiratory illnesses and discussed which foods are most rich in vitamin D. Ultimately, I aim to provide an understanding of the mechanisms by which vitamin D is acquired and the most effective amounts that people should regularly consume in order to strengthen their immune system.Methods: All of the case studies cited in this review were found through Google Scholar or NCBI by search queries such as “Vitamin D supplementation to treat respiratory illness.” Additional information regarding vaccinations and medications was sourced from the FDA and information about the nutritional value of foods was obtained from the USDA.Results: Vitamin D has been shown to have many beneficial effects on patients suffering from both respiratory and non-respiratory illnesses. These benefits include, but are not limited to, lowered susceptibility to infection and lower bacterial counts, reduced symptoms of illness, increased serum 25(OH)D, and corrected vitamin D deficiency.Conclusions: Given the striking symptomatic, molecular, and pathological similarities between infection from SARS-CoV-2 and other respiratory illnesses such as influenza, the positive results from vitamin D supplementation suggest that vitamin D may be a viable treatment option for SARS-CoV-2 symptoms. Through the consumption of vitamin D-rich foods like UV-exposed mushrooms, salmon, and trout, low serum 25(OH)D levels could be corrected and the reduction of symptoms could be naturally facilitated. Through the induction of cathelicidin and defensin, the regulation of cytokines, and the increased production of anti-microbial peptides, vitamin D has the potential to act as a natural treatment option without adverse side-effects like those caused by chloroquine and other proposed drugs.Keywords: Vitamin D; Deficiency; Respiratory Illness; COVID-19; Influenza; Cathelicidin; Defensin; SARS-CoV-2; ACE2; ANG II.