High Vitamin D levels can help you fight-off COVID-19

Healthy levels of Vitamin D can help you avoid SARS-CoV-2 infections and may improve your body’s response to this disease, new studies show

A new study found that COVID-19 patients who received high doses of vitamin D were less likely to require intensive care, compared to patients who did not receive this vitamin. Another study found a significant correlation between vitamin D levels and the risk of SARS-CoV-2 infection. These findings add to previous research showing a protective effect of vitamin D in our body.


What is Vitamin D?


Vitamin D is not a really a vitamin, but a secosteroid, a type of molecule very similar to steroids, biologically active compounds that have multiple functions in the body. Vitamins, on the other hand, are a type of micronutrient, essential for optimal metabolic functions.

Vitamin D can be found as two forms, vitamin D3, which is synthesized in the skin and vitamin D2, which is found in plants and mushrooms. Vitamin D3 is produced in the skin through a two-step process involving ultraviolet B light (UVB) and a compound called 7-DHC, which functions as a vitamin D substrate. In other words, when UVB light reaches 7-DCH, this chemical goes through a transformation process that ends with the formation of vitamin D3.  Hence, you need to get minimum levels of sun exposure in order to stimulate the production of vitamin D in your skin.

However, in order for vitamin D3 to function in our body, it first needs to be converted into 25-hydroxyvitamin D or 25OHD, a process that occurs mostly in the liver. 25(OH)D is then converted to its active form, 25(OH)2D, a process that occurs in the kidneys.  25(OH)2D is the bioactive vitamin D molecule that circulates in the blood and can interact with many enzymes to participate in different body functions. For more information on this process, see this article.


Functions of Vitamin D


The primary function of 25(OH)2D, the bioactive form of vitamin D, is to stimulate the absorption of calcium from the gut, promoting skeletal health. Other important functions of vitamin D include:

      • Reduction of inflammation
      • Modulation of various biological processes, like:
        • cell growth
        • neuromuscular function
        • immunity, and
        • glucose metabolism
      • Modulation of genes involved in cell proliferation, differentiation, and apoptosis (cell death) (Del Valle 2011, Erdman 2012)


Studies have also found associations between levels of vitamin D in the body and multiple conditions, including cardiovascular diseases, serum lipid concentrations, inflammation, glucose metabolism disorders, weight gain, infectious diseases, multiple sclerosis, mood disorders, declining cognitive function, impaired physical functioning, and all-cause mortality (Autier 2014).


Vitamin D and COVID-19


In recent years, studies have identified a protective role of vitamin D in reducing the risk of respiratory tract infections (Beard 2011, Hewison 2012, Greiller 2015, Wei 2015, Coussens 2017, Lang 2017, Gruber-Bzura 2018). For example, vitamin D has been shown to:

      • Help maintain cellular tight junctions, gap junctions and adherens junctions, which keep pathogens outside our body.
      • Enhance cellular innate immunity through the induction of antimicrobial molecules
      • Promote cellular immunity by reducing the cytokine storm produced by the innate immune system.


Our innate immune system produces pro-inflammatory and anti-inflammatory chemicals called cytokines in response to bacterial or viral infections, like the virus causing COVID-19. Administering vitamin D can regulate the production of some of these cytokines, reducing the expression of pro-inflammatory cytokines and increases the expression of anti-inflammatory cytokines by macrophages.  Vitamin D can also modulate the responses of different T cells, resulting in a reduction of inflammatory responses.

Another mechanism through which vitamin D influences body function is through its interaction with the vitamin D Receptor (VDR), binds to 25(OH)2D. VDR belongs to a special type of protein called transcription factor, which interact with specific molecules to promote the expression of certain genes. The highest concentration of this receptor is in tissues involved with the maintenance of calcium homeostasis, such as the intestine, kidney and bones. However, it is now well known that the VDR is also found in many other tissues and cells that are not involved with calcium homeostasis, such as the pancreas, skin, pituitary, breast, colon and prostate cancer cells, and immune cells. The vitamin D receptor regulates the function of more than 900 genes involved in various physiological functions in these cells and tissues.


New research


      • Vitamin D and health outcomes in COVID-19 patients

        A new study has shown that treating COVID-19 patients with high doses of vitamin D, in the form of Calcifediol, improves their health outcomes, preventing the need for intensive care. The study focused on COVID-19 patients who developed Acute Respiratory Distress Syndrome (ARDS) and compared their health outcomes with and without the administration of vitamin D, in addition to the standard of care treatment.


The results of this study strongly support the protective role of vitamin D against complications associated with ARDS and COVID-19. Out of the 50 patients included in this study who received vitamin D, only 1 patient experienced complications and was moved to the intensive care unit (ICU). In contrast, out of 26 patients who did not receive vitamin D, 13 (half of them) suffered complications and were transferred to the ICU and two of these patients died from their condition.

This study shows that the use of high doses of vitamin D, in the form Calcifediol, significantly reduces the severity of COVID-19, reducing the need for ICU treatment. While further studies are needed to confirm the outcomes of this study, vitamin D supplementation stands as a promising approach for people affected by COVID-19.


      • Vitamin D supplementation may also help people gain some protection against COVID-19, according to some studies (Reviewed in Grant 2018). In a recent study, published on September 17 in the journal PLoS One, researchers found a significant correlation between levels of vitamin D and a positive SARS-CoV-2 test.


The study analysed the health outcomes of 191,779 patients tested for SARS-CoV-2 across the United States. Their analyses revealed that patients who had deficient levels of 25-hydroxyvitamin D [25(OH)D] had higher levels of infection, compared to patients who had healthier levels of vitamin D.

Overall, these findings strongly suggest that keeping healthy levels of vitamin D may improve your body’s capacity to respond against the SARS-CoV-2 virus.


How much vitamin D do you need?


This is an important question to consider. In order to obtain the beneficial effects of UVB light and stimulate your vitamin D production, you need to expose your skin to sunlight. According to Australian official recommendations, 50 nmol/L represents the optimal level of vitamin D in adults.

Vitamin D is mostly obtained from the action of sunlight on the skin – about 90% of the vitamin D in our body is produced this way. The remaining 10% is commonly obtained from dietary sources.

The best way to boost your vitamin D levels is through sun exposure. However, the effectiveness of sun exposure depends on where you live, the season of the year (summer vs winter), time of day, your skin colour and how much clothes you are wearing.

For example, during summer you might get all the daily vitamin D you need from 10 minutes of exposure to the sun. But, during winter, it’s a different story. In fact, during winter, not all Australians are producing optimal levels of vitamin D. The most recent data from the Australian Health Survey shows that:

      • About one in four Australian adults (23%) had a vitamin D deficiency
      • Vitamin D rates of deficiency are low summer (14%) and much higher in winter (36%)
      • Current data shows the following deficiency levels by state during winter:
        • Victoria – 49%
        • ACT – 49%
        • Tasmania – 43%
        • Queensland – 15%
        • Northern Territory – 17%
        • Western Australia – 28%
      • Across Australia in twenty adults (5%) were taking vitamin D supplements during 2011–12.


Vitamin D is an important component of a healthy body, but it is important not to exceed the recommended levels. Excess vitamin D can result in toxic outcomes, called vitamin D toxicity, which can influence conditions like heart attack, stroke, kidney stones, headache, nausea, vomiting, diarrhea, anorexia, weight loss, and low bone density.


Are you at risk of vitamin D deficiency?


Certain skin types and certain lifestyles may increase your risk of vitamin D deficiency. For example,

      • If you are dark-skinned you will need more time under the sun, as melanin, the pigment responsible for skin colour, reduces UV penetration.
      • If you cover your most of your skin when going outside, or if you live indoors most of the time, you might not be generating enough vitamin D
      • Infants and babies of vitamin D – deficient mothers are usually at risk
      • Certain conditions and medicines may reduce your body’s ability to absorb vitamin D


If you think you are at risk of vitamin D deficiency, don’t worry too much, there are ways to boost your vitamin D sources. Natural sunlight is the best way to boost your vitamin D levels. However, before going out under the sun for long periods of time, it is important to be mindful about the risk of excessive sun exposure. Skin cancer is a major problem in Australia, especially due to the high levels of UV radiation it receives and the high number of fair-skinned people inhabiting it. It is estimated that 2 out of 3 Australians will develop skin cancer by the age of 70.

Another way to help improve your levels of vitamin D is through diet, just be sure you select foods rich in vitamin D.


What are good dietary sources of vitamin D?


      • Certain fatty fish, salmon, herring and mackerel are rich in vitamin D.
      • Eggs are also a good source of vitamin D, but be sure to select free-range eggs, to ensure chickens were exposed to plenty of sunlight.
      • Unfortified cod liver oil is also a rich source of vitamin D, providing up to 1000 international units (IU) per serving.
      • Certain mushrooms, like cremini or portobello, are good sources of vitamin D.


For more information on foods rich in vitamin D, visit this government website.

All things considered, before making any changes to your lifestyle, consult with your doctor or health professional for advice on what changes are best for you.


Vitamin D and health at the Australian Centre for Functional Medicine


At the Australian Centre for Functional Medicine, we are constantly updating our clinical practice with the outcomes of research studies on vitamin D.

Our approach with vitamin D and health starts with an evaluation of your diet and lifestyle and identification of any potential underlying problems that affecting micronutrient intake. At the Australian Centre for Functional Medicine we understand that 100% of micronutrients, including vitamin D, are absorbed in the small intestine and colon, and any malfunctions in these organs, due to gut dysbiosis, infections or SIBO, will result in poor absorption of vitamin D and other important micronutrients.

At the Australian Centre for Functional Medicine, we will test the health of your gut and ensure your body function is optimal. After we have addressed any underlying conditions and optimised your diet and lifestyle, we monitor your vitamin D status through regular blood testing.

We also recommend optimal lifestyle changes to optimise your natural production of vitamin D through sunlight. Our approach is mindful of the inherent risks in Australia of excessive sun exposure and we develop a plan that will help you get the vitamin D you need while protecting your skin from harmful exposure.



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