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Vitamin D: The Super Immunity Nutrient

By Dr. Chad Walding, DPT, NativePath Co-Founder

As scientists and doctors search high and low for answers to the current coronavirus pandemic, one vitamin, in particular, seems to have taken the spotlight -- vitamin D.

With several studies supporting a possible role of vitamin D in the treatment and prevention of coronavirus, the question presents; is vitamin D the answer to the COVID-19 pandemic?

In this article, I'm going to walk you through what vitamin D is, what role it plays in immunity, and how it may affect outcomes of COVID-19.

Finally, we'll uncover some simple yet effective ways to avoid a deficiency in this crucial vitamin.

What Is Vitamin D?

Vitamin D is a fat-soluble vitamin that can be found in small amounts in some foods but is primarily synthesized internally through sunlight exposure on your skin.

The most well-known job of vitamin D is in calcium homeostasis. It promotes the absorption of this crucial mineral in your gut, and maintains serum levels of both calcium and phosphate to ensure proper bone mineralization. As a bone health-enhancing nutrient, vitamin D also plays a role in bone growth and remodeling.

Therefore, it should come as no surprise that when your vitamin D levels are low, one of the most significant risk factors is osteoporosis.

What many people don’t realize, however, is that vitamin D actually plays a role in almost every system of your body. Aside from bone health, vitamin D is also a vital nutrient for cellular growth, neuromuscular function, inflammation, and immunity [1].

Role of Vitamin D In The Immune System

Research is uncovering more and more the crucial activities that vitamin D carries out in your immune system. In fact, this fat-soluble vitamin plays essential roles in both adaptive and innate immunity.

You can think of innate immunity as your body's first response to a foreign invader. Innate immunity typically comes into play within a few hours of an immune trigger. Adaptive immunity, on the other hand, is a learned immune response that your body “adapts” to overtime. While adaptive immunity may take longer to kick into gear, this immune response is more targeted and efficient once triggered.

As a key nutrient for both innate and adaptive immunity, vitamin D plays several roles in enhancing immune function, including[2][3]:

  • Protection against Infections
  • Calming inflammation
  • Combating autoimmune disease
  • Enhancing the effects of macrophages and monocytes (white blood cells)
  • Bridging the adaptive and innate immune responses
  • Inhibiting inflammatory signaling molecules
  • Upregulating the function of dendritic cells (cells which present antigens to other cells of the immune system)

What’s more, research shows that immune cells such as B cells and T cells are capable of synthesizing the active form of vitamin D -- further underlining its importance to immune function.

Interestingly, vitamin D unwittingly played a role in the treatment of infectious diseases like tuberculosis (TB) for decades before antibiotic treatments were found.

Back in the day, patients with TB were sent to sanatoriums, where one of the primary treatments was exposure to sunlight. The belief at the time was that the sunlight could directly kill the TB. With sunlight being the main route for vitamin D synthesis in your body, it's now understood that it was the vitamin D, not the sunlight itself, that helped these patients recover from TB[4].

Vitamin D Deficiency

Unfortunately, vitamin D deficiency is incredibly common. In fact, it’s estimated that about one billion people worldwide have a deficiency in vitamin D, while 50% of the population has vitamin D insufficiency. Right here in the United States, about 35% of the adult population is deficient in vitamin D[5].


So why is everyone missing out on this crucial nutrient?

There are several factors that affect vitamin D status, chief among them being sunlight exposure. About 50-90% of vitamin D is absorbed through sunlight, while the rest is obtained through diet.

The most vulnerable groups for vitamin D deficiency are the elderly and obese populations, along with those that are hospitalized.

It's clear that getting enough exposure to sunlight is vital for vitamin D status. Still, there are a handful of other factors that can contribute to vitamin D deficiency as well, these include[6]:

  • Malabsorption syndromes like celiac disease, short bowel syndrome, gastric bypass, and cystic fibrosis that inhibit your body’s ability to absorb vitamin D.
  • Certain medications (like laxatives and steroids) that enhance the activity of enzymes which speed up the degradation of vitamin D in your body.
  • People with chronic liver disease or chronic kidney disease are at risk due to the role that these organs play in the activation of vitamin D. 

If you think about the way that most cultures operate these days, with most people spending their days working inside buildings with no natural sunlight, it’s no surprise that so many people are deficient in vitamin D. On top of that, our country is famously over-medicated, which only serves to further drive vitamin D deficiency.

And here is where things get even more troublesome, low levels of vitamin D is associated with an increased risk of[5][1]:

  • Cancer
  • Osteoporosis
  • Cardiovascular disease
  • Diabetes
  • Autoimmune diseases
  • Depression
  • Fractures and falls
  • Influenza
  • Infections

With heart disease and cancer being the top two leading causes of death in the United States, the essential nature of vitamin D sufficiency really comes into focus[7].

Vitamin D and COVID-19

With the current pandemic, there's a lot of talk about whether vitamin D status may play a role in the virus's progression. Vitamin D is such a crucial aspect of immunity; it would make sense that having sufficient levels of this nutrient might affect the outcome of infection.

However, before jumping to conclusions or making assumptions, it’s always important to look at the facts.

Research into the connection between COVID-19 and vitamin D status is showing that regions that tend to be vitamin D deficient are experiencing higher rates of infection and death from the coronavirus. An example of this would be southern Europe versus northern Europe.

In southern European countries like Italy and Spain, where vitamin D status is low, the incidence and spread of coronavirus is much more significant than in the northern European countries. This may be due to the fact that people in the north are much more likely to consume vitamin D-rich foods like cod liver oil, while in the south, the darker complexions can make it harder to absorb vitamin D from the sun[8].

In a meta-analysis of over 10,000 patients, researchers found that vitamin D was protective against respiratory tract infections (like the coronavirus), and supplementation with vitamin D was an effective treatment for those with low vitamin D status[9].

The role that vitamin D plays in respiratory viruses is likely twofold:
Vitamin D supports the production of antimicrobial compounds in the respiratory tract, making it difficult for viruses to thrive and spread.
Vitamin D has anti-inflammatory properties, which could calm the inflammatory cascade caused by infections like COVID-19.

While the research thus far is undoubtedly compelling, at present, there is no cut and dry answer as to whether vitamin D status is an underlying risk factor for the coronavirus.

What is clear, however, is that this vitamin is crucial to immunity and plays an essential role in protecting your body against foreign invaders and imbalances like cancer, heart disease, infectious disease, and autoimmune disorders[10].

How do You Know If You Have Low Vitamin D Levels?

With the prevalence of vitamin D deficiency in the United States, keeping an eye on your vitamin D status is essential.

This is especially important if you’re over 60 years old, take certain medications, work inside most of the time, are overweight, or have a darker skin complexion. Also, if you have any underlying gastrointestinal issues or diseases of the liver or kidney, you may be at greater risk for deficiency.

The signs and symptoms of vitamin D deficiency may include fatigue, muscle pain or cramps, or mood changes. Unfortunately, these symptoms can be attributed to a number of different conditions, making it challenging to pinpoint vitamin D deficiency through signs and symptoms alone.

Therefore, the best way to stay on top of your vitamin D status is to get your levels checked by your doctor.

How To Support Your Vitamin D Levels Naturally

If your vitamin D levels are low, or you’re concerned in general about vitamin D sufficiency, there are several ways that you can naturally support your body’s vitamin D status.

Some of the most effective ways to enhance vitamin D status include:

Exposure to Sunlight

As mentioned before, sunlight exposure accounts for 50-90% of vitamin D absorption. Research shows that twenty minutes of sunshine daily, with over 40% of skin exposed, is required to prevent vitamin D deficiency.

Therefore, a simple way to enhance your vitamin D status would be getting outside more often. Even a couple of short walks throughout the day, or eating lunch outside during your lunch break could make a difference[10].

Food Sources

One way that vitamin D differs from most other vitamins and minerals is that food is not going to be your primary source. Unfortunately, most nutritional sources of vitamin D provide only small amounts of this nutrient, making sunlight exposure and supplementation your primary methods for enhancing vitamin D status.

With that being said, there are certain foods like fatty fish (mackerel, salmon, and sardines), mushrooms (shiitake in particular), and fortified products like milk that can help to up your vitamin D intake[11].


For many people, supplementing with vitamin D is the most effective way to enhance vitamin D status. Getting outside can be a challenge with the busy pace of many people's lives. And as previously mentioned, food sources of vitamin D are scant, and not the most optimal route for enhancing vitamin D status.

Research shows that globally, up to 47% of vitamin D intake may come from vitamin D supplementation. When looking for a vitamin D supplement, be sure to choose one that includes vitamin D3 as opposed to D2. Research shows that vitamin D3 (which is primarily found in animal sources) is far superior at raising the levels of vitamin D in your body as compared to vitamin D2[12].

What’s more, vitamin D2 tends to be cheaper, so many supplement manufacturers that are trying to cut corners will go for this less bioavailable option.

Balance Is Key

Whether you’re concerned about the current global pandemic, or just want to ensure that your immune system is working optimally, getting a grip on your vitamin D status is a great place to start.

However, there is never a one-size-fits-all approach to health and wellbeing. The best way to protect yourself from the ups and downs of life is to find balance in your daily lifestyle and diet.

Keeping your body healthy doesn’t have to be a stressful endeavor.

In fact, your body will naturally go through phases where your natural homeostasis will be challenged. Your job is to simply get yourself back on track, and replete any deficiencies or imbalances that have occurred.

And there is no better way to do that than with Native Defense!

Nature’s Best Immune-Boosting Nutrients In One Daily Dose... 

Jam-packed with Vitamin D, Vitamin C, Zinc, Quercetin, Elderberry, Siberian Ginseng

Check it out here!



  1. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3738984/
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2954005/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356951/
  6. https://www.ncbi.nlm.nih.gov/books/NBK532266/
  7. https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm
  8. https://health.clevelandclinic.org/can-vitamin-d-prevent-covid-19/
  9. https://www.thelancet.com/journals/landia/article/PIIS2213-8587(20)30183-2/fulltext
  10. https://www.ncbi.nlm.nih.gov/books/NBK532266/
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3738984/
  12. https://pubmed.ncbi.nlm.nih.gov/22552031/

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Medical Disclaimer
This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Chad Walding nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement, or lifestyle program.

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