Vitamin D: A Low-Hanging Fruit in COVID-19?

A young girl standing in front of the apple tree with two apples cover her eyes with phase vitamin D and covid 19

Vitamin D is one of the most common natural health supplements at local pharmacies. There are numerous studies supporting its benefits in strengthening our bones, increasing muscle strength, helping ward off depression and possibly preventing cancer.

What Does Vitamin D Have to Do with COVID-19?

Several news reports on vitamin D were released this week and were based on observational data from a number of countries.

These various countries looked back retrospectively at their outbreaks and have found an inverse association between vitamin D levels and COVID-19 outcomes.  This seems to indicate that there may be some benefit to taking Vitamin D to prevent adverse outcomes from COVID-19 infections.

Does Vitamin D Play a Role in Immune Modulation?

In general, the patients with the lowest levels of vitamin D in their blood streams seemed to be more likely to have a severe case of COVID-19, as well as higher mortality rates. The opposite effect has been seen in the infected individuals who had higher levels of vitamin D.

The differences in outcomes were not small either.  The risk of severe infections was shown statistically to be reduced by 15.6% in the patients with normal vitamin D levels compared to those who were deficient in it.

One of the authors, Dr. Kenny from Trinity College in Dublin, Ireland feels that although she admits the data is far short of conclusive, it is robust enough that she has called upon the Irish government to update their current guidelines. She feels it is a “matter of urgency” that they encourage all adults to take vitamin D supplements during the COVID-19 crisis.

This potential effect has a scientific explanation that makes sense as well. It is well established in studies, that vitamin D has an “immune-modulating” effect and can lower inflammation within the body.

As such, vitamin D seems to be able to suppress our adaptive immune system which regulates our cytokine levels (these are a large group of proteins that are released by some of the cells in our immune system and act to regulate inflammation and the production of blood cells within the body) thereby, reducing the risk of the so-called “cytokine storm” that seems to immediately precede life threatening respiratory issues with this infection.

What is the Role of Vitamin D Fortification?

The researchers also feel that this recommendation for vitamin D supplementation is a good idea, regardless of where you live in the world or how much time you spend outdoors. Vitamin D has long been known as the “sunshine” vitamin because it is produced in your skin in response to sun exposure.

Their support for this recommendation is partially based upon the fact that Northern Italy and Spain have had some of the highest COVID-19 mortality rates in the world. Vitamin D deficiency is very high in these countries despite their sunny climates. This is quite possibly due to the fact they do not fortify their foods with vitamin D as we, in North America and many more northern European countries do. Countries in Europe with much higher vitamin D levels, such as Norway and Finland have fared much better in their COVID-19 mortality rates.

Ethnic Minorities Disproportionately Affected

It is also well-recognized that COVID-19 disproportionately affects black and Asian minority ethnic (BAME) individuals.

In Britain people from minority ethnic groups, such as those with African or South Asian ancestry, make up a third of all confirmed cases of Covid-19 in critical care, even though they account for just 14 percent of the population. They also experience higher levels of poverty, chronic diseases and vitamin D deficiencies.

At least one medical group, the British Association of Physicians of Indian Origin, has urged all British health care workers from minority backgrounds to consider taking vitamin D supplements as a precaution.

But two recent studies using data from the U.K. Biobank, a long running project that has tracked the health of a half million people aged 40 to 69, cast doubt on the links between vitamin D and COVID-19.

One group of researchers found that participants who recently tested positive for coronavirus were more likely to have had very low or deficient levels of vitamin D compared to other participants. But the association disappeared after the results were adjusted for factors like age, race, obesity and socioeconomic status.

Testing and Governmental Recommendations During COVID-19

The recommended dose of vitamin D to be taken, seems to be a matter of opinion. Most feel that the current Health Canada recommendations offer a very wide range (between 400 to 800IU depending upon your age) however, most of us would be better served by taking 1000 to 2000 IU’s a day. This will result in blood levels that are sufficient to maintain bone health and normal calcium metabolism in healthy people.

However, there are no additional recommendations specific to vitamin D intake during the COVID-19 pandemic.

Where to Get Vitamin D?

Luckily, there is no shortage of easy ways to increase your vitamin D intake.


  1. Becky McCall. Vitamin D: A Low-Hanging Fruit in COVID-19?
  2. Ron and Marla Chapleau. Ask the Pharmacist.

Anahad O’Connor. Exploring the Links Between Coronavirus and Vitamin D

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