Does Vitamin D Help Minimize the Risk for COVID-19 and other Infections?

The study with the most downloads in the past year (62,590) and the most views (178,562) is another vitamin D study2 by Bhattoa, which found that vitamin D supplementation reduced the risk of influenza and COVID-19 infections and deaths. The coauthors of my paper, Grant and Baggerly, were also coauthors of this paper.

Recommendation of Vitamin D in COVID

A third vitamin D study by Annweiler et al also ranked first among the most cited studies in the past 12 months. In this study, vitamin D supplementation was found to improve survival in frail elderly hospitalized with COVID-19.

Data from 14 observational studies suggest that vitamin D blood levels are inversely correlated with the incidence and/or severity of COVID-19.

All of this is incredibly encouraging and refutes the ridiculous claim that there is “no scientific basis” for recommending vitamin D for COVID. In fact, data from 14 observational studies (as of September 27, 2020) – summarized in Table 1 of our paper – suggest that vitamin D blood levels are inversely correlated with COVID-19 incidence and/or severity.

Furthermore, the evidence generally meets Hill’s criteria for causality in a biological system (i.e., strength of association, consistency of evidence, temporality, biological gradient, plausibility or mechanism of action, and coherence, although coherence remains to be experimentally verified).

Mechanisms of Action

As discussed in our work, adequate vitamin D supply may reduce the risk of COVID-19 and other respiratory infections through several mechanisms, including the following:

  • Reduction of the survival of viruses
  • Inhibition of replication of viruses
  • Reduction of inflammatory cytokine production
  • Maintenance of endothelial integrity (endothelial dysfunction contributes to vascular inflammation and impaired blood clotting, two
    hallmarks of severe COVID-19)
  • Increase in angiotensin-converting enzyme 2 (ACE2) levels – Angiotensin II is a natural peptide hormone that increases blood pressure by stimulating aldosterone. ACE2 normally consumes angiotensin I, thereby lowering the concentration of angiotensin II. However, in SARS-CoV-2 infection, ACE2 is downregulated, leading to excessive accumulation of angiotensin II, which exacerbates the infection.
  • Enhancement of overall immune function through modulation of innate and adaptive immune responses.
  • Reduction of dyspnea
  • Improving overall lung function
  • Supporting the production of surfactants in the lungs, which promote fluid excretion

In my view, vitamin D optimization is one of the simplest, least expensive, and most effective strategies to reduce the risk of severe SARS-CoV-2 infection and other respiratory infections.

Vitamin D optimization is especially important for dark-skinned people (who tend to have lower levels than whites if they do not spend much time in the sun), the elderly, and people with chronic pre-existing conditions.

All of these are also risk factors for COVID-19, so population-wide optimization of vitamin D levels could significantly improve COVID outcomes in those most at risk.

Vitamin D also reduces the risk of several important chronic diseases and comorbidities associated with poor COVID-19 prognosis, including obesity, type 2 diabetes, hypertension, and heart disease. All of these factors make vitamin D an important component of COVID-19 prevention and treatment.

Vitamin D helps prevent these diseases because it is a fat-soluble steroid hormone that enters almost every cell in the body and travels to the nucleus to influence the optimization of 2,000 to 3,000 genes to become a healthier person.

Vitamin D is a key Component for Optimal Immune Function

While the official narrative now is that the human body is defenseless without gene-based intervention (i.e., mRNA- or DNA-based COVID injections), anyone who can still think clearly will recognize the nonsense of this argument. The truth is that your body is well equipped to deal with just about any infection, provided your immune system is functioning properly, because that is your body’s first line of defense.

Vitamin D receptors are found in a wide variety of tissues and cells, including your immune cells. This means that vitamin D plays an important role specifically in your immune function. If vitamin D is lacking, your immune system is compromised, which in turn makes you more susceptible to infections of all kinds.

In the video of this article, Dr. Roger Seheult gives an overview of how vitamin D works and its benefits, both for respiratory infections in general and for COVID-19. Importantly, vitamin D is a steroid hormone that can pass through cell membranes into the nucleus and controls the expression of genes. Thus, it is not just a simple vitamin that is required as a cofactor. It can actually influence the behavior and function of cells in our bodies.

As Seheult notes, vitamin D:

  • Stimulates “the innate immune response that provides frontline protection against infectious agents.”
  • Increases the expression of antimicrobial peptides in your monocytes and neutrophils – both of which play an important role in COVID-19
  • Increases the expression of an antimicrobial peptide called human cathelicidin, “which is of particular importance in host defense against respiratory pathogens.”

Higher vitamin D levels reduce Risk of COVID Infection

While Seheult also discusses a number of studies examining vitamin D in the context of respiratory diseases other than COVID-19, SARS-CoV-2-specific studies have found that COVID-19 is far more common in individuals with vitamin D deficiency.

In one study, 82.2% of COVID-19 patients studied had vitamin D deficiency, compared with 47.2% of population-based controls. (The mean vitamin D level was 13.8 ± 7.2 ng/ml, compared with 20.9 ± 7.4 ng/ml in controls).

In addition, blood vitamin D levels were found to be inversely correlated with D-dimer levels (a measure of blood clotting). Many COVID-19 patients have elevated D-dimer levels, which are associated with blood clots. Vitamin D has also been associated with a lower risk of testing positive for COVID-19 in the first place.

The largest observational study to date, which examined data from 191,779 U.S. patients, found that of those with vitamin D levels below 20 ng/ml (deficiency), 12.5% tested positive for SARS-CoV-2, compared with 8.1% of those who had vitamin D levels between 30 and 34 ng/ml (adequacy), and only 5.9% of those who had optimal vitamin D levels of 55 ng/ml or higher. According to the authors:

SARS-CoV-2 positivity is strongly and inversely associated with circulating 25(OH)D levels, a relationship that exists across latitudes, races/ethnicities, both sexes, and age groups

Vitamin D Status Influences the Severity of COVID-19

COVID-19 patients who have higher vitamin D levels also tend to have a milder disease course and better overall outcome. One study found that the risk of severe COVID-19 disease and associated deaths virtually disappears when vitamin D levels are above 30 ng/ml (75 nmol/L).

In another study, COVID-19 patients with vitamin D levels between 21 ng/mL (50 nmol/L) and 29 ng/mL (75 nmol/L) had a 12.55-fold higher risk of death than patients with levels above 30 ng/mL. A level below 20 ng/mL was associated with a12-fold higher risk of death.

Our vitamin D paper also includes data from 14 observational studies showing that vitamin D blood levels are inversely correlated with the incidence and/or severity of COVID-19. This is quite logical given that vitamin D regulates the production of inflammatory cytokines – a lethal feature of COVID-19 – and is an important regulator of the immune system.

Seheult also reviews studies showing that COVID-19 outcomes appear to be related to UVB exposure. One such study, for example, found a significant difference in mortality depending on whether patients lived above or below the 35th parallel north. As the authors note:

… the hypothesis is not that vitamin D would protect against SARS-CoV-2 infection, but that it may be very important in preventing the cytokine storm and subsequent acute respiratory distress syndrome that is often the cause of mortality.

How to Optimize Your Vitamin D Level

While mainstream medicine insists that a vitamin D level of about 20 ng/ml is sufficient, this really only applies to bone health. For optimal health, immune function and disease prevention, you should have a blood level between 60 ng/ml and 80 ng/ml year-round. In Europe, the target levels are between 150 nmol/L and 200 nmol/L.

If you live in a sunny location and get reasonable year-round sun exposure, you may not need supplements. The Minder app is a helpful tool for determining how much vitamin D your body can make depending on where you live and other individual factors.

I walk on the beach for about an hour every day, wearing only shorts and a cap – and no sunscreen, as it filters out the ultraviolet rays that stimulate vitamin D production – and haven’t needed an oral supplement in over a decade. (Remember, the only way to be sure you are getting enough sun exposure is to get tested, preferably twice a year, in summer and winter.)

Unfortunately, there are many people who do not get enough sun exposure for one reason or another, and in these cases, oral vitamin D supplementation may be necessary. Remember that the most important factor here is your blood level, not the dose. So get tested before you start taking it so you know your baseline.

Below is a brief summary of how to determine if you need an oral supplement and what dosage is ideal for you:

  1. Measure your vitamin D level first – One of the easiest and least expensive ways to measure your vitamin D level is to participate in GrassrootsHealth’s Personalized Nutrition Project, which includes a vitamin D testing kit. Once you know your blood level, you can determine the dose you need to maintain or improve your level.
  2. Determine your individual vitamin D dosage – You can either use the chart below or GrassrootsHealth’s vitamin D* calculator to do this. To convert ng/ml to the European measure (nmol/L), simply multiply the ng/ml value by 2.5. To calculate how much vitamin D you are absorbing in addition to your supplementation through regular sun exposure, use the DMinder app.
  3. Retest in three to six months – Finally, you will need to measure your vitamin D level again in three to six months to assess how your sun exposure and/or supplement dose is working for you.

Simple Way to Improve Your Vitamin D Intake

Keep in mind that the specific dosage needed to maintain optimal vitamin D levels can vary greatly from person to person and depends on a variety of factors such as skin pigmentation, age and weight. The health of your gut can also play an important role in how well you absorb the vitamin D you take.

In a healthy gut, beneficial bacteria produce butyrate by breaking down fiber. Butyrate, in turn, helps increase vitamin D levels. The more butyrate you have, the more vitamin D your body can absorb.

Another factor that can affect vitamin D absorption is your magnesium level. Magnesium is needed for the conversion of vitamin D into its active form. According to a scientific study published in 2018, about half of Americans who take vitamin D supplements don’t get any significant benefit because the vitamin D is simply stored in its inactive form, and the reason is inadequate magnesium levels.

Research by GrassrootsHealth shows that it takes 146% more vitamin D to reach a blood level of 40 ng/ml (100 nmol/L) when not taking supplemental magnesium, compared to taking vitamin D with at least 400 mg of magnesium per day.

Vitamin K2 intake may also affect the required vitamin D dosage. According to GrassrootsHealth,34 “combined intake of magnesium and vitamin K2 has a greater effect on vitamin D levels than intake of magnesium and vitamin K2,” and “those taking both magnesium and vitamin K2 have higher vitamin D levels for a given vitamin D intake than those taking either magnesium or vitamin K2 or neither.”

Data from nearly 3,000 people showed that 244% more oral vitamin D was needed for 50% of the population to reach a vitamin D level of 40 ng/ml (100 nmol/L) if they were not taking magnesium and vitamin K2 at the same time. So a simple way to optimize vitamin D intake is to take it along with magnesium and K2.

Watch the Video here:


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