The Importance of Vitamin D in the Age of COVID


“…higher blood levels of vitamin D appear to be correlated with lower incidence or severity of COVID-19.”


Vitamin D: Essential for Good Health

Vitamin D is a fat-soluble vitamin that is naturally present in several food sources such as trout, salmon, tuna, cheese and egg yolks. Another way it is introduced to our diets is through supplementation. Vitamin D is a very common supplement and can be found on the shelves of nearly any grocery or health food store. Many big-name chain stores carry and sell Vitamin D. The familiarity and abundance of this vitamin is likely responsible, ironically, for some of the misunderstandings surrounding it. These include the ideas that “All vitamin D is the same” and “Vitamin D from the sun is adequate.” There are also some surprising benefits that are associated with taking Vitamin D that many people are unaware of, including the affects it has in the body in relation to COVID-19.

Vitamin D Deficiency

It is estimated that 1 billion people world-wide are vitamin D deficient[1] and between 70% and 97% of Canadians are vitamin D insufficient.[2] While vitamin D deficiency is prevalent in through out the world, it is most common in those over 65 years of age and/or those with darker skin. It can be diagnosed with a blood test called 25-hydroxyvitamin D. The most concerning challenges that vitamin D deficiency can create are rickets (softening of the bones during childhood) osteomalacia (softening of the bones in adults), hypocalcemia (low blood calcium) and hypophosphatemia (low blood phosphate).

Beyond these issues, adequately treating vitamin D deficiencies may create improvement in other body systems such as cardiovascular systems, immune systems, and muscular systems. As a result, symptoms of vitamin D deficiency may also include:

  • Fatigue/poor sleep,
  • depression,
  • muscle loss,
  • loss of appetite,
  • aching bones,
  • and getting ill frequently.

There have also been indications that lower vitamin D levels has a significant impact on mental health and that adequate treatment can help with depression and other mental disorders, particularly in women.[3] According to the WHO, depression affects approximately 280 million people world wide, and is about 50% more common in women than men.[4]

How people take vitamin D can also play a role in deficiency/insufficiency. If it is not taken correctly, it will just pass through the gut and not absorb to the cells. Vitamin D should not be taken on an empty stomach as it is a fat-soluble vitamin. It does not dissolve in water and for maximum absorption it is best taken with a large meal that includes some fat.

Are All Vitamin D Sources the Same?

It is easy to assume that all vitamin D is the same when purchasing supplements, especially when one is in a hurry at the grocery store and just wants to finish their shopping. The fact of the matter is that all vitamin D is not the same. The main difference is found in the purity of raw material sourcing.

Sourcing raw ingredients is usually the most critical step in creating a high-quality product. It is impossible to create a top tier health product using sub-par and low-quality ingredients – it would be unreasonable to think any different. With the introduction of China into the world-wide (and particularly American) health product raw ingredient market in the early 2000’s, the costs of source materials decreased significantly and the quality of ingredients across the industry was largely sacrificed on the altar of profit.

In order to differentiate the quality of their materials, the most reputable raw ingredient suppliers provide documentation verifying the processes and origin of their products right up to point of sale. This is essential in order to ensure that the raw materials that are used to create health products are, indeed, healthy. There are many, many companies that do not provide such documentation and therefore call into question the quality (even safety!) of their raw materials. Care to take a guess as to whose materials are cheaper?

Vitamin D and COVID-19

In 2020, a report was published to that stated “Vitamin D and its receptor are considered to be vital in the protection against respiratory infections.”[5] There have been other significant discoveries recently specifically connecting COVID-19 and vitamin D as well. New research has “revealed that higher blood levels of vitamin D appear to be correlated with lower incidence or severity of COVID-19.”[6] This has to do with the importance of vitamin D in relation to the body’s natural immune system. According to Luke Huber, ND, MBA, “…the data does suggest that vitamin D levels may play a role, in combination with other therapies, in strengthening the immune system to resist the virus.”[7]

Other analysis reported that while vitamin D deficiency was not associated with a higher rate of infection from COVID-19, it presented a 64% increase in severity when compared with milder cases of the infection.[8] The author went on to report that, “we observed a positive association between vitamin D deficiency and the severity of the disease. From this perspective, evaluating blood vitamin D levels could be considered in the clinical practice of health professionals. Moreover, vitamin D supplementation could be considered in patients with vitamin D deficiency and insufficiency, if they have COVID-19.”[9]

Doctor’s Choice Vitamin D3

Doctor’s Choice is committed to creating the very best quality health products, including the Vitamin D3 it produces. As indicated above, the greatest differentiation of vitamin D products will nearly always be found in the quality of the source materials. The market is currently flooded with vitamin D products that are derived from suspect ingredients and GMO-based materials. Products that have been created with verified and guaranteed raw ingredients will consistently deliver better value for the dollar.

For the longest time, our formulator and CEO, Eldon Dahl, DNM, did not produce a vitamin D product. The primary reason was he had not connected with a raw material supplier that could provide elite ingredients along with the documentation that supported it. If he could not produce the highest quality product possible that guaranteed purity of origin, there was no point moving forward.

Eventually, however, after being in the natural health industry for over 35 years, Dahl connected with an excellent raw material provider offering premium USP grade ingredients to create a superior vitamin D3 – a company Dahl was willing to put his name beside.

Doctor’s Choice Pure Vitamin D3 is sourced from lanolin derived from sheep’s wool. All the wool is harvested from a single herd of sheep, ensuring the consistency of quality through-out – much like a single crop of grapes ensures the consistency through-out a cuvée of wine. These sheep are non-GMO, anti-biotic and vaccine free and verified as such through documentation provided by the supplier. As we have said many times before, nothing but the best goes into Doctor’s Choice Products.

Additional Reading:




[3] Vitamin D and Depression: Where is all the Sunshine? – PMC (

[4] Depressive disorder (depression) (


[6] CRN Foundation Applauds New Research Linking Vitamin D and COVID-19

Angela Sabarese | November 9, 2021

[7] CRN Foundation Applauds New Research Linking Vitamin D and COVID-19

Angela Sabarese | November 9, 2021