Vitamin D's relationship to COVID

Even before Covid-19 put the world into lockdown in early 2020, scientists were exploring the role vitamin D plays in our health and wellbeing.


Known as the sunshine vitamin because our bodies can produce it when exposed to the sun’s rays, vitamin D is well-known for its role in keeping our bones and teeth healthy. But there’s also increasing evidence of the vital part it plays in the way our immune systems function.


Studies suggest that getting enough vitamin D can help prevent everything from diabetes to cancer and depression. And that may be reason enough for you to make sure you are getting your daily dose.


However, there’s also been plenty of research into the link between vitamin D and upper respiratory tract illnesses, such as the flu.


Doctors first suspected there might be a link because of the seasonal nature of these illnesses. They tend to be more prevalent in the fall and winter months – exactly the times when we get the least sunlight.


A large meta-study published in the BMJ in 2017 reviewed the evidence. Looking at high-quality studies, the authors concluded that vitamin D supplementation does protect against acute respiratory tract infection.


What does all of this have to do with Covid-19? Well, as we all know, Covid-19 is a virus that mainly affects the upper respiratory tract, which is why some of its best-known symptoms are coughing and problems breathing.


Since research had already suggested a link between vitamin D levels and other upper respiratory tract infections, it is no wonder that doctors soon began to wonder whether there might also be a relationship between our chances of getting ill from Covid-19 and our vitamin D intake.


Low Vitamin D Levels in Covid-19 Patients?

Even early in the pandemic, headlines began to emerge suggesting a correlation between vitamin D deficiency and the likelihood of ending up in hospital with Covid-19.


Groups who are generally lower in vitamin D, such as the elderly, black people, and other people of color, were quickly identified as being amongst the most vulnerable to the virus.


Similarly, research showed that countries further from the equator had more Covid-19 deaths than those closer to it. Since countries on the equator get more sunlight, the authors of this study suggested a link between vitamin D levels and the risk of dying from Covid-19.


At first, the link between vitamin D and Covid-19 was just a theory. But when researchers started to look closer, they found evidence that it could be true.


One study published in The Journal of Clinical Endocrinology & Metabolism compared vitamin D levels in Covid patients with those of the general population. The researchers found that over 80% of the hospitalized patients were vitamin D deficient, while only 47.2% of the general population lacked vitamin D.


Another 2020 study looked at people who had been measured for vitamin D levels in the year leading up to the pandemic. Those with lower levels of vitamin D were 1.77 times more likely to test positive for Covid-19.


Of course, a correlation between vitamin D levels and the risk of catching Covid-19 doesn’t necessarily mean that taking a vitamin D supplement helps to protect against the virus. But the association between them was enough for doctors and patients alike to want to know more.


Do Vitamin D Supplements Lower the Risk of Covid-19?

Having discovered the potential relationship between vitamin D and Covid-19, researchers began to test whether taking a vitamin D supplement could help protect people against the worst effects of the illness.


Early results have been mixed. One Spanish study was thought to show a clear benefit to taking vitamin D supplements, reporting an 80% reduction in admissions to the ICU and a 60% reduction in deaths from Covid-19.


However, the study subsequently came under criticism for not choosing patients in a sufficiently random way, and it was removed from Lancet.


Other studies found no clear evidence that supplementing with vitamin D helps to reduce the symptoms of Covid-19.


Research into the role of vitamin D in protecting against Covid-19 is ongoing. Although it has had such a wide-felt impact on our way of life, Covid-19 is still a new illness. There’s just not been much time yet for doctors and scientists to dive deep into the potential of vitamin D for treating it.


However, there are some large trials taking place currently that should help us learn more about the relationship between Covid-19 and vitamin D levels.


In the UK, a team of researchers coordinated by the Queen Mary University of London are carrying out a randomized controlled trial involving 6200 participants. This is known as the CORONAVIT study.


Meanwhile, at the University of Chicago, Dr. David Meltzer and his team are conducting several clinical trials to investigate how vitamin D supplementation affects Covid-19 risks.


Once the results of these trials are published, we should know more about whether supplementing with vitamin D can protect against Covid-19.


Should You Take a Vitamin D Supplement?

As yet, there’s not enough research available to say for sure that vitamin D helps prevent Covid-19. So, taking a vitamin D supplement on its own isn’t a magic bullet against the virus.


However, vitamin D has plenty of benefits for our health, including boosting our immune system and protecting against upper respiratory tract infections.


Many of us are deficient in vitamin D. So, taking steps to make sure we get enough can only help us stay healthy and well.


How to Get Enough Vitamin D

Sunlight is the best natural source of vitamin D. However, it is hard for those of us living away from the equator to get enough sun exposure to meet our daily needs. That’s especially true during the fall and winter when the days are shorter, and the weather isn’t exactly conducive to sunbathing.


Some foods contain vitamin D too. Oily fish, eggs, and mushrooms are all sources of dietary vitamin D. Other foods, such as breakfast cereals, are fortified with vitamin D to help you meet your daily goals.


Here at Vitapod, we make getting more vitamin D easy and delicious by adding it to our pods. This means you can easily look after your immune system while rehydrating your body.


For example, our Immunity+ Blackberry and Mint shots contain plenty of immune-boosting ingredients, including added vitamin D. And this essential vitamin is also an ingredient in every flavor of our Hydra+ range.





National Cancer Institute, Vitamin D and Cancer Prevention


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Hernández, J. L., Nan, D., Fernandez-Ayala, M., García-Unzueta, M., Hernández-Hernández, M. A., López-Hoyos, M., ... & Martínez-Taboada, V. M. (2021). Vitamin D status in hospitalized patients with SARS-CoV-2 infection. The Journal of Clinical Endocrinology & Metabolism106(3), e1343-e1353.


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Clinical Trials, Trial of Vitamin D to Reduce Risk and Severity of COVID-19 and Other Acute Respiratory Infections (CORONAVIT)


The University of Chicago, Vitamin D and COVID-19 Research

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