Vitamin D Vs. COVID-19
The health crisis that’s currently plaguing our globe, otherwise known as COVID-19, has distinctive risk factors associated with specific demographics with underlying health conditions. 25-hydroxyvitamin D, the chemical form of vitamin D exists in a similar fashion, in that vitamin D deficiency is also a major global health pandemic, with over 50% of the population experiencing such an insufficiency. These issues have corresponding severe health related developments within the immune system. Factors such as obesity, diabetes, heart problems, age and race are common traits that both COVID-19 patients and people experiencing a deficiency of 25-hydroxyvitamin D may share. Due to vitamin D deficiency's association with an increased risk of pulmonary diseases and its relative symptoms to COVID-19, there is speculation as to whether low 25-hydroxyvitamin D levels are correlated to the severity of COVID-19 an individual may contract.
What is COVID-19?
Over 55.6 million people around the world have contracted COVID-19, and 1.34 million have died as a result. The United States is surpassing the number of cases within other countries across the world with 12 million infected and a death toll of 256 thousand. COVID-19 is a respiratory illness pandemic which was first detected in Wuhan, Hubei province, China. According to What Is COVID-19, “coronaviruses are a large family of viruses that are known to cause illnesses ranging from the common cold to more severe diseases such as Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome'' (MERS). Doctors refer to the virus as a respiratory tract infection because it can affect the respiratory system, which includes the nose, throat, windpipe, and lungs. Studies show that people with underlying health conditions such as diabetes, obesity, and/or older age have increased risks of developing more serious and possibly fatal symptoms of COVID-19 due to immunocompromisation. Similarly, vitamin D deficiency often occurs most frequently in people with these underlying health conditions.
Vitamin D’s Health Benefits
Vitamin D deficiency is a worldwide health issue with an estimated one billion people having that deficiency. Specifically, 50% of the population has a vitamin D insufficiency. On a biological level, vitamin D stimulates the synthesis of calcium transport proteins in the small intestine, enhancing the absorption of dietary calcium and therapy. This reduces the risk of osteomalacia in adults and rickets in children (Sizar, 2020). The sun’s ultraviolet rays synthesize the production of vitamin D in the skin, which is then transferred to the liver and converted to 25-hydroxyvitamin D. Both vitamin D2 and D3 are found in food, but this contributes to less than 10% of sources of vitamin D. Found in natural sources such as oily fish (salmon, mackerel, sardines), cod liver oil, organ meats, and egg yolks as well as supplements, vitamin D is readily accessible (Green, 2015). A deficiency in vitamin D can result in severe health conditions concerning bone density and various disorders, and it can play a vital role in the development of autoimmune diseases.
There are two types of 25-hydroxyvitamin D - vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D3 and D2 deficiency can result in obesity, diabetes, hypertension, depression, and neurodegenerative diseases such as Alzheimer’s disease (Zahid, 2010). People who suffer from vitamin D deficiency have a higher risk of developing symptoms of COVID-19 as supported by the connection of health conditions, mainly concerning infections of the respiratory tract. One study of 489 people found that those who had a 25-hydroxyvitamin D deficiency were more likely to test positive for the virus that causes COVID-19 than people who had normal levels of vitamin D2 and D3 (“Can vitamin D Protect against the Coronavirus Disease 2019”).
Vitamin D Deficiency vs. COVID-19 Mortality Rates
Those of older age are especially prone to the global health crises concerning vitamin D deficiency and COVID-19. Vitamin D decreases with age in the skin, and there is an increased mortality risk of people over 65 if infected with COVID-19, as demonstrated in Figure 1. According to the World Health Organization, studies show that in Europe, over 95% of deaths related to COVID-19 occurred in those older than 60 years while more than 50% involved people aged 80 years or older. In the United States, 8 out of 10 deaths related to COVID-19 reported in the United States have been among adults aged 65 years and older. About 50 to 60% of nursing home residents and hospitalized patients had vitamin D deficiency (Sizar, 2020).
Figure 1: Vitamin D deficiency’s comparison to COVID-19 deaths among the elderly in European countries. (Gonzalez, 2014)
Similar to age, skin pigmentation is a concerning factor in the risk of contracting COVID-19. Melanin reduces the production of vitamin D, which is associated with exposure to ultraviolet radiation in sunlight. This disadvantage of lessened vitamin D production results in an increased risk of vitamin D deficiency among people with darker pigmentation. COVID-19 has similar statistics concerning the racial disparities in recorded cases worldwide. Despite plentiful sunshine on countries along the equator – parts of Asia, Africa, and South America – there is an increased mortality rate for ethnic minority groups. This could partially be due to lessened environmental health conditions, but the increased risk that less pigmentation brings is still quite threatening. Individuals with darker skin pigmentation require six to ten times as much sun exposure as light-skinned individuals. Therefore, this barrier to gaining the appropriate amount of vitamin D can result in mild to severe health conditions if the individual is infected with COVID-19 (Zahid, 2010).
Health Conditions vs. Vitamin D
Both COVID-19 and vitamin D deficiency can have serious and even fatal consequences as a result of certain responses from the respiratory system, as shown in Figure 2. One meta-analysis found that people who took vitamin D supplements, particularly those who had low vitamin D levels, were less likely to develop acute respiratory tract infections such as COVID-19. An important defense for the cells in the immune system is provided by regulatory T cells, commonly known as Tregs. High levels of Treg cells help fight and prevent immune diseases by regulating other cells within the immune system. A study of a group of COVID-19 patients found their Treg levels to be severely low. According to some scientists, “these observations suggest that if Treg levels can be increased, this might be of benefit in diminishing the severity of viral disease and perhaps of COVID-19” (E Kenneth, 2020)
Fortunately, vitamin D supplements are beneficial for increasing regulatory T cells, which suggests that healthy consumption of vitamin D supplements may be a favorable method of assisting COVID-19 patients. Another common disease associated with COVID-19 patients is thrombosis, or a blockage of blood in the veins, which corresponds with elevated D-dimer levels. D-dimer is a small protein that is created when blood clots dissolve after a healed wound. High D-dimer levels prevent doctors from finding where the clot is located and if individuals have a clotting disorder or not. High D-dimers are also associated with liver disease and various other infections. Vitamin D helps regulate thrombotic pathways, therefore vitamin D depletion has a severe effect on the increase of thrombotic levels (E Kenneth et al, 2020).
Figure 2: Demonstrated the comparison of health related symptoms of vitamin D levels and COVID-19
How to Prevent a Vitamin D Deficiency
The recommended dose of 25-hydroxyvitamin D is 600 IU each day for adults 70 and younger. As vitamin D levels decrease with age, adults over 70 are recommended 800 IU each day. Ways to prevent vitamin D deficiency include 15 to 20 minutes of exposure to the sun with at least 40% of the skin exposed, a balanced diet of foods that has a high percentage of vitamin D such as tuna, salmon, mushrooms, and orange juice, as well as prescribed vitamin supplements from a doctor (Zahid, 2010).
Although vitamin D levels and COVID-19 mortality rates have similar health-related symptoms, there needs to be more data analyses within patients to have an accurate diagnostic of vitamin D levels being a predominant factor in the increase of COVID-19 development within the immune system. The 25-hydroxyvitamin D test is troublesome; the two chemical components needed for vitamin analysis are quite difficult to separate from the proteins within the blood, thus making it difficult to get an accurate result. Vaccines for COVID-19 are currently undergoing dispersion across the globe, but perhaps a new vaccine proposal may have a chemical component similar to 25-hydroxyvitamin D given the various factors that prove vitamin D’s benefits towards human health.
Written by: Jaylin Osbourne
Works Cited
“Can vitamin D Protect against the Coronavirus Disease 2019 (COVID-19)?” Mayo Clinic,
Mayo Foundation for Medical Education and Research, 2 Oct. 2020, www.mayoclinic.org/diseases-conditions/coronavirus/expert-answers/coronavirus-and-vitamin-d/faq-20493088.
Green, R. “Vitamin D Deficiency and Insufficiency in Africa and the Middle East, despite
Year-Round Sunny Days | Green | South African Medical Journal.” SAMJ, Health & Medical Publishing Group, 22 Sept. 2015, www.samj.org.za/index.php/samj/article/view/10070/6859.
Naeem, Zahid. “Vitamin d deficiency- an ignored epidemic.” International journal of health
sciences vol. 4,1 (2010): V-VI.
“Office of Dietary Supplements - vitamin D.” National Institutes of Health,
ods.od.nih.gov/factsheets/VitaminD-HealthProfessional. Accessed 30 Nov. 2020.
Palacios, Cristina, and Lilliana Gonzalez. “Is vitamin D deficiency a major global public health
problem?.” The Journal of steroid biochemistry and molecular biology vol. 144 Pt A (2014): 138-45. doi:10.1016/j.jsbmb.2013.11.003
Sizar, Omeed, et al. “Vitamin D Deficiency.” NCBI, StatPearls Publishing LLC, 2020,
Weir, E Kenneth et al. “Does vitamin D deficiency increase the severity of COVID-19?.”
Clinical medicine (London, England) vol. 20,4 (2020): e107-e108. doi:10.7861/clinmed.2020-0301
“What Is COVID-19?” Coronavirus, 30 Nov. 2020, coronavirus.dc.gov/page/what-COVID-19.
World Health Organization. “Supporting Older People during the COVID-19 Pandemic Is
Everyone’s Business.” World Health Organization (Europe), 3 Apr. 2020, www.euro.who.int/en/health-topics/health-emergencies/coronavirus-COVID-19/news/news/2020/4/supporting-older-people-during-the-COVID-19-pandemic-is-everyones-business#:%7E:text=Over%2095%25%20of%20these,other%20chronic%20underlying%20conditions.
Image Sources
Figure 1: Palacios, Cristina, and Lilliana Gonzalez. “Is vitamin D deficiency a major global
public health problem?.” The Journal of steroid biochemistry and molecular biology vol. 144 Pt A (2014): 138-45. doi:10.1016/j.jsbmb.2013.11.003
Figure 2: Gilbert, Christopher R et al. “Vitamin D deficiency and chronic lung disease.”
Canadian respiratory journal vol. 16,3 (2009): 75-80. doi:10.1155/2009/829130