Vitamin D levels and Covid-19 severity

A whole world has almost come to halt for a while due to a tiny collection of biomolecules (virus).  Fortunately, it now started returning back to some new form of normalcy but that too at slow pace. Everyone is aware about the impact the disease has created over the world. Here there is no need to mention about it. But today we are going to discuss about the Vitamin D and how it can be very important to combat with Covid-19.

Why people are dying with Covid-19:

The X-Ray reports of patients suffering from Covid-19 that are in advanced stages suggest difficulty in imaging the lung tissue due to excellent flooding from the fluids. This is common in many of the acute respiratory diseases such as SARS (Severe Acute Respiratory Syndrome) and MERS (Middle-East Respiratory Syndrome) which are supposed to be the ancestors. So, what is causing this lung damage?  Experts have come to known that the key for the virus to enter the human body and bind is ACE2 protein located on the surface of many cells. Using the spike-like protein on its surface, the Covid-19 virus binds to ACE2 similar to a key being inserted into a lock.  Now the scientists know the key mechanism for virus binding, so why don’t we just cut this receptor?  Turns out that It’s not as that simple.  ACE2 receptors play a vital role in regulating the processes such as blood pressure, inflammation and wound healing.  There is also another protein called angiotensin II (ANG II) that is responsible increasing the blood pressure and inflammation. ANGII protein in excess can be very harmful to the blood vessel linings and various tissues, if in excess.  And that’s where the ACE2 comes in picture. ACE2 converts ANG II to other molecules that counteract its harmful effects.  As the Covid-19 directly attacks the ACE2 protein, the blood pressure could increase beyond the limits filling water in lungs and could become the reason of death of patient, often sometimes very quickly.

Vitamin D and Covid-19:

The potential use of Vitamin D in the prevention and treatment of acute respiratory diseases date back to 1930, when cod liver oil, a source of Vitamin D was employed to reduce industrial absenteeism due to common cold.  The debate in favour of it and against it is from long time.  Meta-analyses of randomised controlled trials conducted from 2007–20 reveal protective effects of vitamin D against acute respiratory infections.4 Now, before diving into the subject lets us introduce another vital protein called CRP (C-Reactive Protein).  CRP is a protein made by liver during inflammation, including the cases where ANGII is not regulated properly as per the earlier discussion.  CRP can cause pain, redness, and swelling in the injured or affected area. Normally, we have low levels of CRP protein.  If CRP is present beyond limits it may be sign of serious infection or disorder.

There are many good reasons to postulate that vitamin D has potential in combating Covid-19, both in the early growth and later hyperinflammatory phases of COVID-19.  The Covid-19 patients in advanced stage have known to show higher level of CRP.   Various recent studies as well as studies from the past have tried to establish the correlation between the CRP and Vitamin D [include reference]. Recent studies are showing that there exists inverse correlation (correlation coefficient ranging from -0.84 to -1) between high CRP and 25(OH)D1. These studies cite the deficiency of Vitamin D as one of the main reasons for the high level of CRP.  Lower circulating 25(OH)D concentrations have also been reported to associate with more susceptibility with the virus.

There have been numerous hospital-based trials to check Vitamin D can be used as treatment [reference].  Recent studies from a University in Germany and USA has further verified the effect of Vitamin D1,2,3.  But it is challenging to generate the strong clinical evidence at this early stage particularly since it takes time to fully understand the entire gamut of the Covid-19 infection mechanisms and its effects, particularly for severe cases.  The severe Covid-19 infected patients approaching to the hospitals are generally in hyper inflammatory conditions and it may be too late to get any benefits from the supplementation of Vitamin D at that stage.  Hence, prevention is the key.   Knowing your Vitamin-D level is ever more vital, particularly considering   Second, it can be hard to show the effect of a micronutrients, which has potent anti-inflammatory actions and now represents the standard of care in severe disease.  Nevertheless, given that CRP is a surrogate marker for cytokine storm caused during the inflammation, and is shown to be associated with Vitamin-D deficiency, based on retrospective data and indirect evidence we see a possible role of Vitamin-D in reducing complications attributed to unregulated inflammation.  Maintaining healthy Vitamin-D level may not be a bad idea in any case as there is nothing to lose, and potentially much to gain to stay healthy and ready to fight the infections!


Note:  Opinions expressed in this blog are based on the author’s individual research and is not evaluated by the disease experts!   Consult your physicians for guidance related to your specific situation.



  2.  Explained: German study on benefit of Vitamin-D to fight Covid-19:
  3.  Experts explain benefits of Vitamin-D:
  4. The Lancet: