Vitamin D has been getting some press lately, although not enough in our opinion. There have been several studies looking at COVID-19 and vitamin D levels. The research is very promising and important to talk about as we continue to deal with this virus. We should do everything we can to stay healthy; there are things within our control to protect ourselves. Please refer to our blog post, The Magic Pill, from this summer in which we discuss some of these important tactics as well as highlight some of the early studies on vitamin D deficiency and poor outcomes with COVID. We will discuss more about COVID and vitamin D, but there are so many other benefits that are worth bringing to light (pun intended).

What is Vitamin D?

Vitamin D is a fat soluble “vitamin” that actually acts more like a hormone; it is much more than a supplement! When you eat foods with vitamin D or get it from the sun, the body converts it to a steroid hormone. In this form, it provides us with many benefits for health:

  • Plays an important role in regulating insulin and blood sugar. 
  • It’s believed to have a role in regulating serotonin, the body’s mood boosting chemical.
  • Helps to decrease muscle cramps and spasms. 
  • Modulates cell growth
  • Some gene expression is also modulated in part by vitamin D.
  • Helps to modulate the body’s immune response, and has anti-inflammatory and anti-infective roles. It can reduce the risk of viral infections by lowering the viral replication rates, reducing proinflammatory cytokines and increasing anti-inflammatory cytokines. 
  • Vitamin D improves gut permeability and can help repair a leaky gut – we could go down a rabbit whole on how this alone improves immune function; see our blog post on the microbiome.
  • The more well-known benefit is for bone health, but it also has been shown to improve function in all tissues such as the skin, brain and muscle tissue.

COVID-19 and Vitamin D

As we mentioned above, and in our last blog post, there is growing evidence that the outcomes from COVID-19 infections are much better in patients with adequate vitamin D levels. In this paper, the author goes as far to say that “correction of vitamin D deficiency might be of major relevance for the reduction of the clinical burden of the ongoing and future outbreaks of SARS-CoV-2 infection.” The study showed higher hospitalizations and deaths with vitamin D deficiency, independent of major comorbidities. 

In Europe they are calling this a pandemic of vitamin D deficiency. This study suggests that there is significant evidence of the protective effect of vitamin D against COVID-19, and that older adults are at higher risk for vitamin D deficiency. Could that be a link to the overwhelming numbers of deaths in our older population? 

There is now more research on vitamin D as a treatment as well. This study of 76 patients had some compelling results. In the group not treated with vitamin D, 50% were admitted to the ICU and there were two deaths. In the group treated with high levels of vitamin D only 2% ended up in the ICU and there were no deaths. Of course there’s a lot more research to be done, but this is pretty exciting progress.

How much do we need? How much is too much? 

To find out how much you need, the best thing to do is have your blood levels measured. The U.S. Endocrine Society recommends that serum vitamin D levels above 30 ng/ml are adequate, and below 20 ng/ml are deficient. Current thinking among some doctors and nutrition experts is that optimum levels should be at 40 ng/ml. In the United States, approximately 70% of the population is below 30 ng/ml and only 13% of adults and 5% of children have the ideal levels of 40 ng/ml. 

Vitamin D is not found in large quantities in food, so supplementation is recommended to get adequate amounts, especially if your time exposed to sunlight is limited. Vitamin D expert, Dr. Rhonda Patrick says supplementation with vitamin D3 is a good way to ensure you get adequate vitamin D. 1,000 IU of vitamin D per day, in most people, will raise serum levels by about 5 ng/ml. The upper tolerable intake level set by the Institute of Medicine is 4,000 IU. One study showed that people that were considered to be vitamin D deficient were able to raise their serum levels to sufficient levels after supplementing with 4,000 IU of vitamin D3 per day.

The question of toxicity is a common concern with any supplement. Excessive sun exposure doesn’t cause vitamin D toxicity because the body limits the amount of this vitamin it produces from the sun. It is possible to have too much vitamin D from supplementation, but oftentimes the issue is too much calcium that is not able to be absorbed. As Dr. Joseph Mercola discusses in this interview with Ben Greenfield, it’s important to look at other supplements that work synergistically with vitamin D. Calcium is important for bone health, but if it cannot be absorbed in the bones, it can cause build up in the arteries. Ideally one should take magnesium which helps to activate vitamin D, thus requiring less vitamin D for it to be effective, and vitamin K2 which helps drive the calcium to the bones.

As always, it’s best to discuss any supplementation with your doctor, but with the growing cases of COVID-19, and with a vaccine that could be weeks or months away, we strongly feel that the more we can do to help ourselves and take control of our health, the better! If something as simple as taking a vitamin can help improve many aspects of our health, we would be crazy not to do it. We can take this into our own hands. We can do everything we can to be healthy. That’s the best defense we have.


If you are looking for high quality supplements, we always recommend Thorne. We are not associated with them in any way but we trust their ingredients and their testing. They are among the most recommended and highly respected supplement companies in the industry. 


*Disclaimer: The information in this blog is for informational purposes only. Please always consult your doctor before considering any new diet, supplementation, or other changes to your normal nutrition and exercise routine.