Don't Miss Out

Subscribe to OCA's News & Alerts.

More Than 80% of COVID Patients Are Vitamin D Deficient

Aside from insulin resistance, discussed in “The Real Pandemic Is Insulin Resistance,” vitamin D deficiency has emerged as a primary risk factor for severe COVID-19 infection and death. Higher vitamin D levels have even been shown to lower your risk of testing positive for the virus in the first place.

Getting the word out about this — especially to the Black community and the elderly in nursing homes — could have a significant impact on future hospitalization and death rates from this virus.

If you have a loved one in a nursing home, taking the time to talk to the medical management about vitamin D testing and supplementation could also make a big difference in the general health of all the residents, as vitamin D is something that can strengthen your immune system in a matter of a few weeks and has many health benefits beside lowering your risk of viral illness. 

Vast Majority of COVID-19 Patients Have Vitamin D Deficiency

According to a Spanish study1,2,3 published online October 27, 2020, in The Journal of Clinical Endocrinology & Metabolism, 82.2% of COVID-19 patients tested were found to be deficient in vitamin D, the medical term for which is 25-hydroxycholecalciferol (25OHD). 

The researchers compared the vitamin D levels of 216 COVID-19 patients and 197 population-based controls, finding that hospitalized COVID-19 patients had a higher prevalence of deficiency and had lower vitamin D levels overall. As reported by the authors:4

“In COVID-19 patients, mean± SD 25OHD levels were 13.8±7.2 ng/ml, compared to 20.9 ±7.4 ng/ml in controls. 25OHD values were lower in men than in women. Vitamin D deficiency was found in 82.2% of COVID-19 cases and 47.2% of population-based controls.

25OHD inversely correlate to serum ferritin and D-dimer levels. Vitamin D deficient COVID-19 patients had a greater prevalence of hypertension and cardiovascular diseases, raised serum ferritin and troponin levels, as well as a longer length of hospital stay than those with serum 25 OHD levels ≥ 20 ng/ml.”

While this particular study failed to find a correlation between vitamin D levels and disease severity, other studies have shown patients with higher levels do tend to have milder disease. In fact, one such study5,6 found your risk of developing a severe case of, and dying from, COVID-19 virtually disappears once your vitamin D level gets above 30 ng/mL (75 nmol/L). 

Vitamin D’s Impact on COVID-19 

Back in June 2020, I launched an information campaign about vitamin D that included the release of a downloadable scientific report. This report, as well as a two-minute COVID risk quiz is available on

October 31, 2020, my review paper7 “Evidence Regarding Vitamin D and Risk of COVID-19 and Its Severity,” co-written with William Grant, Ph.D., and Dr. Carol Wagner, both of whom are part of the GrassrootsHealth expert vitamin D panel, was also published in the peer-reviewed journal Nutrients. You can read the paper for free on the journal’s website. It will be officially published later this month. 

As noted in that paper, dark skin color, increased age, pre-existing chronic conditions and vitamin D deficiency are all features of severe COVID disease, and of these, vitamin D deficiency is the only factor that is modifiable. As such, it would be foolish to ignore, especially since vitamin D supplements are readily available and low cost. 

Vitamin D can reduce your risk of COVID-19 and other respiratory infections via several different mechanisms, including but not limited to the following, all of which are discussed in greater detail in our paper:8

  • Reducing the survival and replication of viruses9
  • Reducing inflammatory cytokine production
  • Maintaining endothelial integrity (Endothelial dysfunction contributes to vascular inflammation and impaired blood clotting, two hallmarks of severe COVID-19)
  • Increasing angiotensin-converting enzyme 2 (ACE2) concentrations. As explained in our paper:


“Angiotensin II is a natural peptide hormone best known for increasing blood pressure through stimulating aldosterone. ACE2 normally consumes angiotensin I, thereby lowering its concentrations. However, SARS-CoV-2 infection downregulates ACE2, leading to excessive accumulation of angiotensin II.

Cell cultures of human alveolar type II cells with vitamin D have shown that the SARS-CoV-2 virus interacts with the ACE2 receptor expressed on the surface of lung epithelial cells. Once the virus binds to the ACE2 receptor, it reduces its activity and, in turn, promotes ACE1 activity, forming more angiotensin II, which increases the severity of COVID-19.” 

Vitamin D also boosts your overall immune function by modulating your innate and adaptive immune responses, reduces respiratory distress10 and improves overall lung function, helps produce surfactants in your lungs that aid in fluid clearance.11

It lowers your risk of comorbidities associated with poor COVID-19 prognosis, including obesity,12 Type 2 diabetes,13 high blood pressure14 and heart disease.15 All of these factors make it an important component of COVID-19 prevention and treatment.