Vitamin D for Colds, Flu, and Coronavirus

Sunshine Vitamin D

We associate vitamin D with healthy bones, sunshine, and milk and there's certainly truth in those associations. But the word is out: vitamin D can be a lifesaver. Recent research in high-level medical journals reveals that supplementation with vitamin D consistently lowers a person's risk of developing an acute viral respiratory infection. As recently as 2016, major studies were showing that vitamin D helps prevent colds and flu.

Respiratory infections are sources of misery for tens of millions of people every year. They can take weeks to shake and can be fatal. In the case of the coronavirus, vitamin D supplementation can literally save lives.

Vitamin D helps bolster the immune system in two ways: by increasing the production and effectiveness of peptides in the lungs and reducing inflammation. These peptides, which are very similar to proteins but smaller and somewhat simpler, act as antibiotics. Unlike antibiotics people take for different illnesses, these peptides work to fight off viral and bacterial infections.

Everyone can benefit from vitamin D supplementation, but during the winter months, getting extra vitamin D is vital for good health. Winter is cold and flu season, which coincides with the lowest levels of intense sunlight every year. The body’s ability to produce vitamin D from exposure to sunlight drops to its lowest points, weakening the immune system. At the lowest levels of vitamin D production, we become the most vulnerable to viruses like coronavirus.

But do low levels of vitamin D really contribute to illness? Reliable research says they do. Studies of coronavirus victims and survivors have shown several commonalities, including one that may change the way the virus is treated and prevented. People who suffer the worst outcomes of COVID-19 have serious vitamin D deficiency.

Studies Show Vitamin D’s Effectiveness Fighting Flu and Colds

We've known for decades that vitamin D, along with calcium, is vital for healthy, strong bones. We've also understood that vitamin D can be generated in our tissues when we're exposed to sunlight. But it's only in the last 10 years has the role that vitamin D plays in treating and preventing illness has really leaped into the public's view.

Research studies dating back to 2012 show that taking vitamin D reduces the risk of contracting a cold or flu, especially for those with chronically low vitamin D levels. Meta-studies of vitamin D indicate that it can protect us against viruses that attack through the respiratory system. That includes the common cold, influenza, and the coronavirus. That meta-study involved 25 professional clinical trials pulled from 14 countries and firmly established vitamin D’s effectiveness at preventing cold and flu.

How do we get these benefits from vitamin D?  

Firstly, vitamin D reduces, and in some cases prevents a common, often lethal overreaction of the immune system, the cytokine storm. Cytokines are proteins and protein-like chemicals released by the immune system. There are many different cytokines with many various functions, but they all work as part of the immune system and attempt to keep us healthy. It’s ironic but overproduction of cytokines can be a dangerous condition of its own, often overshadowing the direct harm from the coronavirus. Cytokine storms result when the body’s immune system attacks its own tissues, leading to massive inflammation deep inside the major organs and blood vessels. The cytokine storm causes swelling that damages the lungs, kidneys, blood vessels, and liver.

The cytokine storm is unfortunately a common part of COVID-19. It's theorized that the inflammation of blood vessels all through the body, including those that feed the brain, is responsible for the unusual blot clots found in many people with COVID-19. These blood clots, along with the inflammation that may cause them, are far less common in people with adequate levels of vitamin D.

Another benefit of vitamin D supplementation involves the peptides mentioned above. Because of a gene only humans and other primates have, vitamin D helps tailor the immune system’s response to be more appropriate to real threats. People with severe vitamin D deficiencies thus miss the opportunity to have a higher level of natural anti-viral resistance, both overall and within the lungs.

As people get older, their ability to synthesize vitamin D drops. As well, people who live in areas with little intense sunlight also are vulnerable to lowered levels of D. We need about least 800–1000 IU (20–25 micrograms) of vitamin D3 per day to get the most benefit, especially in cloudier climates and during the winter.

Your Takeaway

  • Vitamin D supplementation is safe
  • Vitamin D is effective at reducing the incidence of viral infections like coronavirus, the common cold, and influenza
  • Vitamin D boosts levels of peptides that act as antibodies in the lungs
  • Vitamin D fights inflammation in the body’s major organs, including the lungs and blood vessels
  • People who are lacking in vitamin D are without a doubt more susceptible not only to the coronavirus but also suffering more severe effects from COVID-19.
  • Vitamin D gives the biggest benefits to people who are vitamin D deficient, but everyone can benefit from vitamin D, especially in cold and flu season or locales `that are consistently cloudy.


If you want to ensure you’re covered from vitamin D deficiency, Saratoga Immune D3fense offers 2000 IU of vitamin D, 250 percent of your daily requirement. Saratoga Immune D3fense is a multi-supplement, proving the proven benefits of zinc, vitamin C, Vitamin D, and selenium for the immune system.

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