Vitamin A: The Missing Link in COVID Prevention and Treatment

Vitamin A: The Missing Link in COVID Prevention and Treatment

My faithful readers know that I believe wholly in the value of vitamin A, and that it has been unfairly maligned. I also believe that the vast majority of us are deficient in vitamin A due to the fact that appreciable amounts are found almost exclusively by consuming liver, and most of us no longer eat this organ meat.

My earlier writings on the subject can be found in these blogs:

Sunglasses, Vitamin A and Your Lungs

Defending Vitamin A

Defending Vitamin A: Part 2

Defending Vitamin A: Part 3

Given my strong belief in the value of vitamin A, I was not surprised to find a detailed study on how important vitamin A is for preventing and treating COVID. I have been recommending it for all forms of influenza and respiratory ailments for years now, so it makes sense that vitamin A would be essential for the prevention and treatment of COVID as well.

Herein I will examine a huge clinical review titled, “A novel hypothesis for COVID-19 pathogenesis: Retinol depletion and retinoid signaling disorder”.

This massive work is extremely detailed and technical, and I will attempt here to summarize it in accessible language, though I will provide a link at the end for those who want to examine the original review.

The Premise

According to our researchers, no definitive treatment protocol has yet been developed for treating COVID, nor has the specific pathology of the disease been clearly determined. Thus, they believe this examination of vitamin A deficiency in the manifestation and severity of COVID symptoms will help in the development of more effective drugs, vaccines, and treatment options. (Or, we could all just ensure that we have an adequate intake of vitamin A.)

They go on to state that the systemic destructive effects of COVID, including damage to the immune system, acute respiratory distress syndrome, and a breakdown of a variety of organ systems, cannot be explained by looking at regular genetic viral mechanisms.

And, in fact, these unusual tendencies of COVID actually “mimics the systemic effect of retinoid signaling disorders”, thus they “hypothesize that the RA signaling disorder plays an essential role in the immunopathogenesis of COVID-19”. (RA refers to Retinoic Acid, a metabolite of vitamin A.)

Essentially they are saying that vitamin A deficiency, and depletion of vitamin A during illness, results in impaired retinoid signaling, which in turn leads to a “dysregulated immune system, defect in Type I interferon synthesis, severe inflammatory process, and destructive systemic multiorgan involvement”.

Part of the problem is that retinoid signaling is also used by the body to recognize viral RNA, and this process uses up vitamin A stores, causing retinol levels to fall below normal levels required for maintaining health.

My readers know how valuable I believe vitamin A to be, but now let’s have a look at how these scientists view vitamin A, giving us a good idea of why they chose this vitamin to focus on.

Vitamin A Metabolism

Vitamin A signaling is necessary for the regulation and maintenance of a wide variety of biological functions, such as growth, development, vision, differentiation, proliferation, and apoptosis, both during the intrauterine development and in adulthood. Vitamin A functions as hormones in regulating the body’s metabolism and promoting growth. When first discovered, it was named as hormone A and growth factor due to its vital role in cell survival and development. Later, it was found to have an anti-infection effect and therefore was referred to as an anti-infectious vitamin.”

During measles epidemics in the 1950s, the WHO added vitamin A to its infection prevention programs, which ultimately “reduced mortality from measles pneumonia by 50% during the epidemic”. Similar benefits were found when vitamin A was used as a supportive therapy with AIDS patients, and vitamin A deficiency is also associated with increased mortality in children.

Retinoid Signaling Mechanism

Vitamin A is intrinsic to the “retinoid signaling mechanism” which is also involved in “transcription”, the first step in gene expression. This involvement in genetic expression indicates to us why vitamin A is essential for the formation, development and function of organs and tissues from embryo to adult. And it explains why “disruption of this signaling causes serious congenital malformations during the embryonic period and causes serious developmental disorders affecting many organ systems in adulthood including the immune system”.

Evidently, the relationship between vitamin A deficiency and immunosuppression is considered a scientifically confirmed fact, as is the role of vitamin A “in regulating the primary immune defense and in keeping the inflammatory process under control during infections”. (As a side note, this makes it clear that we should be taking extra vitamin A when dealing with any type of infection in the body.)

Now, here is where our researchers reveal a clever bit of detective work.

We know that some people infected with COVID have very mild symptoms, while others have very severe symptoms, sometimes leading to death. It has been apparent since the beginning that those most at risk for death are those suffering from comorbidies

(“the simultaneous presence of two or more diseases or medical conditions in a patient”).

Those other diseases and medical conditions that are most linked to severity of COVID symptoms and mortality are primarily “malnutrition, chronic liver and lung diseases, chronic kidney disease, obesity, hepatosteatosis, chronic inflammatory autoimmune and rheumatic diseases, malignancies, organ transplants, and senility”.

The authors of this paper realized that these ailments “also drain the body’s retinol reserves” and, “since retinol stores are weakened in these diseases, the immune defense against SARS-CoV-2 is also impaired”.

It is not only vitamin A which exerts its physiological effects through retinoid receptors but also vitamin D. No surprise there since vitamin A is an often overlooked cofactor of vitamin D (along with magnesium).

Both vitamin A and vitamin D “have similar effects especially on the Central Nervous System and immune system. Their immunomodulatory effect is noteworthy as it may have implications in many human illnesses including autoimmune and COVID-19. The therapeutic effect of VitD in COVID-19 has been recognized but that of VitA has been overlooked. Even though there has not yet been any experimental study on the dynamics of the retinoic signaling in COVID-19, a recent study by George et al., supports our hypothesis. We believe that VitA and VitD signaling have similar but central roles in the pathogenesis of COVID-19, and therefore need further investigation.


Here are the key points summarizing the thesis of the study we are examining:

  • Retinoid signaling plays a central role in the pathogenesis of COVID-19. Both vitamin A and vitamin D employ retinoid signaling.
  • A proper retinoid signaling establishes a balance between regulatory T cells and pro-inflammatory Th17 cells.
  • Dysregulated retinoid signaling suppresses Tregs and favors development of hyperinflammatory Th17 in COVID-19.
  • COVID-19 infection rapidly consumes the body’s retinol leading to dysregulated retinoid signaling and hyperinflammation.
  • This causes a cytokine storm leading to multi-organ system involvement.

Therefore, ensuring people have sufficient vitamin A stores will facilitate proper retinoid signaling, which should prove to be a “valid strategy for management of COVID-19 as well for some other chronic, degenerative, inflammatory, and autoimmune diseases”.

Source: A novel hypothesis for COVID-19 pathogenesis: Retinol depletion and retinoid signaling disorder


How much vitamin A do we need? When I research the vitamin A content of beef liver it appears to range from 18,000 IU to 26,000 IU, per 100 grams, depending on who you believe.

I’ve always thought that a healthy sized serving of beef liver contains about 50,000 IU of vitamin A, but it appears that I got this idea from the Weston Price Foundation, who state that this is the amount found in 4 oz (113 gr) of any mammal liver.

The Price Foundation, which advocates a diet based on our ancestors and indigenous peoples from around the world, go so far as to refer to liver as “Our Most Important Sacred Food”. And, on their website his followers state: “From the work of Weston Price, we can assume that the amount in primitive diets was about 50,000 IU per day.”

My opinion is that one should ingest at least 50,000 IU of vitamin A per week. While the dangers of vitamin A have been grossly exaggerated (see my newsletter links at the top of this article), pregnant women who wish to err on the side of caution should use “emulsified” vitamin A supplements, which is a water-soluble form that will not build up in the body.

My usual protocol for clients who have not been taking vitamin A is to recommend they take 50,000 IU daily for five days (or ten if they are dealing with an ailment related to vitamin A deficiency), then take 30,000 IU, five days a week, until they do not squint on a sunny day. (Squinting on a sunny day, or extreme sensitivity to light are symptoms of vitamin A deficiency.)

After that, I recommend a total of 50,000 IU per week, which can all be taken at once, though must be at a meal containing fat. However, if I find myself squinting again on sunny days, I will up the dosage to 30 – 40,000 IU for a few days. Once the squinting goes away I roll back to the maintenance dose.

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