Can You Protect Yourself Against Covid With Vitamin D? Emerging Research Suggests So



As you may have noticed, winter is here. That means COVID is still here. It still can sicken, maim, and even kill. While we have developed vaccines and treatments for people who have become infected, there are some potential tools from the natural world that may help this situation greatly. It is high time people knew about these things and then consider their application.

Scientific research is uncovering powerful evidence concerning the potency of these options. One vitamin, which is actually a hormone made in the skin when ultraviolet radiation from the sun alters cholesterol, is showing great promise. You may have heard of it: it is vitamin D3.

In effect you may already be taking it, but did you know that it may help protect you from COVID-19? Medical science researchers have known for some time that this particular substance has great power in reducing the risk of respiratory infections such as influenza and bacterial pneumonia. The question is: does vitamin D3 have any influence over COVID-19 viral infections?

I am happy to say that the answer is “yes.” Although it is still an area of active investigation by medical science, it is becoming increasingly clear that vitamin D3 supplementation may become a major weapon in our battle against this deadly virus.

Vitamin D3 Is A Hormone That Interacts With Your DNA

Vitamin D3 is technically not a vitamin at all. Vitamins are substances that cannot be made in the human body, and are essential for health. Vitamin D3 is made in the skin by the interaction of ultraviolet light from the sun with cholesterol. Vitamin D3 is actually a hormone that interacts with the DNA of every cell of the body to produce multiple health promoting and protective effects.

Although it is hard to estimate, science feels that there are between 25,000 and 100,000 genes present in the human genome. Each cell activates a set of these genes to give its distinctive characteristics, and much of this activation occurs under the influence of what we know as messenger molecules or hormones. The vitamin D3 hormone activates at least 1,000 of these genes in most cells influencing cellular function, and through this, overall cellular health.

It has been known for some time that low vitamin D3 levels in human beings increase the risk of infection and serious consequences from viral infections such as influenza. This knowledge is now being extended to COVID-19. It is an area of intense research, and the stakes are high.

Vitamin D3 may reduce not only the chance of infection but also the chance of damage from that infection, and improve your ability to repair your body if an infection has occurred. One thing is for sure, there is no evidence that vitamin D would be harmful in any way with a COVID-19 infection. We can also state without a doubt that vitamin D supplementation is safe and necessary for most people and beneficial to overall health.

Vitamin D3 Helps Produce Internal Antibiotics

Most people don’t know this, but we produce our own antibiotics within our own bodies. Vitamin D is a major factor in activating the system of production of these internal antibiotics. These internal antibiotic chemicals have activity against viral invaders. This is just one level on which vitamin D3 might provide significant protection against COVID-19.

There is also emerging evidence that vitamin D3 might have two effects preventing the COVID-19 infection itself. The COVID-19 virus can attach two proteins on the surface of cells lining the respiratory tract that have something called the ACE receptor protein. COVID-19 cannot easily invade cells that do not have this surface protein, and the amount of this receptor protein appears to determine the risk of infection and its severity. Vitamin D3 reduces the number of ACE2 receptor proteins on the cells of the lining of your respiratory tract, and this may protect against the initial infection. Vitamin D3 also tightens the gaps between cells, which make it more difficult for the virus to go deeper within the body.

Vitamin D3 also has the capacity as a messenger hormone to shift the immune system to a stance protective against infectious problems. If an infection occurs, multiple lines of scientific evidence show that the severity of a COVID 19 infection will be less for people with good vitamin D3 levels. Vitamin D3 is also known to aid in tissue repair following infections.

Optimizing Vitamin D3 Levels

Knowing that vitamin D3 is produced by ultraviolet rays from the sun might tempt you to try to get adequate amounts by increasing your sun exposure. Unfortunately, studies have shown that this is virtually impossible, and it is very difficult to dose your skin exposure carefully. Ultraviolet light rays from the sun are filtered out by atmospheric dust and other particles. This means that especially during the winter, ultraviolet ray exposure is unlikely to produce adequate levels. During the winter the sun is lower in the sky, and the rays have to pass through larger amounts of atmospheric dust and particles.

In both northern and southern latitudes this effect is increased. North of a line drawn above Albuquerque, New Mexico in the United States there simply is not enough ultraviolet rays to produce necessary levels of vitamin D3 with skin exposure alone. This is why virtually every expert on vitamin D3 recommends oral supplementation.

As a physician who has recommended vitamin D3 supplementation to virtually every patient I have interacted with for over two decades, my experience and data from the literature support that virtually every human being could take 2000 international units (I.U.) of vitamin D3 day orally, and most would achieve adequate levels. At this dosage, oral vitamin D3 supplementation is safe for virtually every patient.

Optimizing levels is a little more difficult because the amount of oral supplementation each individual needs varies greatly. My general recommendation for the purposes of this article is to begin with 2000 international units per day. Use this consistently for three months and then measure your 25 hydroxy vitamin D levels by simple blood laboratory testing. You can obtain this through your doctor or by ordering test kits online. The test is not very expensive.

Vitamin D experts generally agree that a 25 hydroxy vitamin D level measured by laboratory of between 60 and 80 is optimal and entirely safe for most people. I, for instance, require 5000 international units a day to achieve this level and I have seen a small number of patients who require as much as 10,000 international units a day to get to optimal levels.

If you are taking a multivitamin there’s a very high chance that you are only getting 400 international units a day. Recently multivitamins have started to increase their dosage of vitamin D3 beyond this 400 international unit RDA level. At some point I hope the government recognizes that it has made an error and increases the RDA for vitamin D to a safe and effective level.

Obtaining And Using Vitamin D3 Supplementation Safely

Vitamin D3 is the only type of vitamin D available over the counter. Although it is becoming increasingly rare, some physicians prescribe vitamin D2 which is the only prescription form, and is now known to be almost worthless as a protective strategy. Vitamin D3 can be obtained at any health food store or any major chain grocery store. Read the amount in each unit on the label of the bottle that you buy.

There are only three circumstances where it may not be advisable for you to take supplementary oral vitamin D3. If you have a family history or a personal history of kidney stones, vitamin D3 may increase your risk. Your doctor may want to perform a baseline 24-hour urine for calcium and oxalate before and after vitamin D supplementation to determine if it is going to increase your risk of kidney stones. There is some scientific evidence that the increased risk of kidney stones could be eliminated by the addition of a magnesium potassium citrate supplement, which is also extremely safe. If you have a rare disease called sarcoidosis or you have cancer you will want to consult with your physician as vitamin D3 supplementation may increase your calcium levels.

Do not take vitamin D supplements suddenly or in amounts exceeding what you need. If you take vitamin D3 all at once in high doses you will actually induce a deeper vitamin D deficiency for a period of time, making you susceptible to the effects of vitamin D3 deficiency. Consistent use at the appropriate dose is the rule for safety. In the great majority of people, vitamin D3 toxicity will not occur until 25 hydroxy vitamin D levels are well above 200 which typically takes around 20,000 international units a day to induce. With vitamin D3 supplementation there is a wide window of safety.

Dr. Bill Schroeder is a board-certified internal medicine specialist physician and molecular biologist. He is a graduate of the University of Arizona School of Medicine’s Associate Program in Integrative Medicine under Dr. Andrew Weil, MD. He can be reached at

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