Vitamin D and It’s Relationship with COVID-19

Studies have found that vitamin D interacts with over 3,000 genes modifying not only calcium absorption and bone mineralization but several other systems necessary for optimal health. One of its important effects is a vital roll in immune system regulation and inflammatory modulation.

Vitamin D has many pivotal rolls in the immune system but some of the most important are:

• Vitamin D directly effects B-Cell and T-Cell (Lymphocyte) proliferation and maturation so our bodies can fight infections.
• Vitamin D helps modify and regulate macrocytes and dendritic cell production helping to manage the inflammatory response.
• Vitamin D supports T-regulatory cells thus helping create an appropriate and balanced immune response.

All these effects lead to a positive and balanced immune and inflammatory response.

Vitamin D Health Benefits

The Vitamin D Deficiency Epidemic

Vitamin D and COVID

To try to understand with relationship between vitamin D and COVID-19 (SARS-CoV-2) we must first understand the limitations in the available research. Currently, most studies are observational or retrospective and can only indicate correlation and not causation. Until more double blind placebo-controlled trials are completed it will be hard to have a definitive consensus on the impact vitamin D may have on COVID-19.

That being said, to date, there are over 50 studies indicating a benefit between taking vitamin D and reducing the impact of COVID-19 on an individual. I wanted to share the data here so at least we can all be aware of what the findings are, despite the limitations of the studies.

Proposed mechanism of action for vitamin D reducing the severity of COVID

Cytokines are signaling molecules in the immune system stimulated by many cell types including lymphocytes and macrophages. Cytokines are a necessary and beneficial part of the immune response…..when they respond appropriately.

Complications arise when cytokines proliferate uncontrollably creating an imbalance commonly referred to as a ‘cytokine storm.’ If a cytokine storm is not slowed and eventually halted, it can lead to Acute Respiratory Distress Syndrome (ARDS), organ damage and ultimately organ failure and death.

Recall I mentioned that vitamin D helps regulate lymphocytes and macrophages? The proposed theory why vitamin D could reduce severity of COVID infections lies in its ability to modulate and slow cytokine production.

Proposed mechanism of action for vitamin D reducing likelihood of infection from COVID

It has been proven that Vitamin D interacts with both the innate (general and front line) immune system as well as the adaptive immune system (antibody production).

Vitamin D has direct anti-viral properties allowing it to help inhibit viral replication. Vitamin D also has been shown to be both anti-inflammatory and immune modulating thus creating a strong immune defense system.

It is proposed that by providing anti-viral support, anti-inflammatory signals and immune modifying properties, vitamin D may reduce the likelihood of acquiring an infection with COVID.

Vitamin D in research…What are the studies saying?

One study showed Vitamin D levels were significantly lower in COVID patients with severe symptoms compared to those with mild symptoms or negative COVID results. All patients admitted to ICU who had ARDS had lower vitamin D levels compared to those without progressive disease.

Unfortunately, 19 patients in this retrospective study died, and all patients who passed away were found to have lower vitamin D levels then those who survived.
Vitamin D and COVID-19 Severity and Related Mortality: A Prospective Study in Italy

Another study involving 216 COVID-19 patients and 197 population-based controls saw significantly lower levels of Vitamin D in the patients hospitalized due to COVID-19. Patients and controls were of similar age and sex. Unlike other studies, this study did not find a relationship between severity of infection and Vitamin D serum levels.

This study also reported that 82.2% of patients positive for COVID-19 were deficient in Vitamin D compared to the population-based controls, where only 47.2% were deficient.
Vitamin D Status in Hospitalized Patients with SARS-CoV-2 Infection

Another study analyzing 489 patients found that those with Vitamin D deficiency (<20 ng/dL) were 1.77 times more likely to test positive for COVID-19 than those with sufficient Vitamin D levels.
Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results

Another study of 76 SARS-CoV-2 positive hospitalized patients, 50 patients were given a high dose of Vitamin D (calcifediol) and 26 patients were not given any Vitamin D. Only one of the 50 patients given vitamin D needed ICU treatment, whereas 13 of the 26 not given Vitamin D needed ICU treatment. Of the patients not given vitamin D two died and of the patients given vitamin D none died.
“Effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for COVID-19: A pilot randomized clinical study”

Interpreting a randomized control trial showing vitamin D has no impact on length of hospital stay from COVID infections

One of our few randomized controlled studies on vitamin D made headlines with its conclusion that vitamin D did not reduce the length of stay in hospitalized patient with COVID infections. 240 hospitalized patients were giving a single dose of 200,000 IU vitamin D and compared to a control group of similar individuals given placebo.

It was determined that the group given vitamin D did not spend less time in the hospital. However, despite the study being randomized and controlled, this study has limitation and result need to be interpreted cautiously as well. The authors excluded all patients requiring invasive mechanical ventilation as well as anyone admitted to the ICU. These exclusions create significant limitations to the study and ultimately excluded severe COVID-19 patients requiring longer hospital stays.

Here is more commentary on the study:

Vitamin D3 to Treat COVID-19 Different Disease, Same Answer

Effect of a Single High Dose of Vitamin D3 on Hospital Length of Stay in Patients With Moderate to Severe COVID-19

In Conclusion…

We of course must acknowledge the limitation of all the studies to date, but it seems very plausible that vitamin D likely plays an important roll in both prevention and reducing severity of COVID-19 and other viral infections.

In my opinion, there is no harm in testing your levels of vitamin D and taking appropriate personalized daily dosing. The up-side of having adequate vitamin D serum levels could be life saving (in more ways then just relating to COVID). I highly recommend that you and your loved ones get your vitamin D levels checked. Vitamin D testing can be done via a finger poke with an at home test kit or through a blood draw. Depending on your private health insurance it might be covered, though not all insurances will reimburse for the test. Regardless I do believe that testing is a good use of your time and money.

They say knowledge is power, and I believe in this case that argument holds true yet again.

In Health,
Dr. Nina Lewis-Larsson
Naturopathic Doctor and owner of Elevated Health Integrative Medical Clinic