Vitamin D : Does it reduce COVID risk?

Jun 03, 2020


Today, everyone is focused on learning about nutrients that boost immunity/immune system to battle the widespread novel coronavirus (SARS-CoV-2) which causes COVID 19. Among all the nutrients, vitamin D, vitamin C and zinc are some of the most talked about immunity boosters. As the virus continues to spread, maintenance of immunity for fighting coronavirus is crucial for every individual.

As of now, the mechanisms through which certain nutrients impact the immune system, and how immune responses fight off a wide range of different pathogens (bacteria, virus, etc.) are not fully understood. There are several studies that prove a strong association of certain nutrients in boosting the immune system/ immune responses.  For the past few weeks, there has been a lot of buzz around vitamin D. People have realized that a vaccine for COVID 19 is a long time away. Also, nations cannot continue to remain in lockdown and have slowly lifted restrictions.. As of now, almost all the cities are open and people have started moving. Everyone started living with the coronavirus. Now everyone is following preventive and protective measures to fight coronavirus. 

There is a lot of buzz about how vitamin D can act as a shield against coronavirus. To what extent is it scientifically/medically true? – this is a crucial question for everyone. Should everyone start taking vitamin D supplements? 

Vitamin D – functions, sources and health risks

Vitamin D is a fat-soluble vitamin that helps the body to absorb calcium which is the main building block of bones and teeth. It also helps in the absorption of magnesium, and phosphate. It is naturally present in very few foods. People can take Vitamin D in 3 different ways – diet, through the skin by exposing the body to sunshine or from supplements (only after doctor consultation).

Apart from the key role of promoting calcium absorption, vitamin D also assists in:

  1. Supporting nervous, immune, and brain system health
  2. Modulation of cell growth
  3. Promoting healthy bones and teeth
  4. Supporting diabetes management and regulating insulin levels
  5. Reduction of inflammation
  6. Supporting cardiovascular health and lung function

Despite the fact that the body can synthesize Vitamin D, a deficiency can occur for many reasons such as skin color (darker-skinned people are at higher risk), sunscreens (protecting the body with clothes), geographical location (people living in northern latitudes are at higher risk), ‘poor absorption, genetics and breastfeeding.

Vitamin D deficiency can lead to diseases like osteoporosis or rickets. If the deficiency continues for a prolonged period, it may result in complications such as chronic diseases, autoimmune diseases, cardiovascular conditions, infectious diseases (notably, upper respiratory tract infections), neurological diseases, and certain cancers such as colon, breast, and prostate. 

Surprisingly, a study conducted by PG Talwalkar (Diabetologist at Shushrusha Hospital in Mumbai) found that 70-90% of the Indians are vitamin D deficient.

How much vitamin D is required for good health??

The amount of vitamin D people should take every day depends on their age.  Vitamin D intake is measured in 2 units – IU or micrograms. IU is a measurement used to measure the activity of some vitamins and other biological substances.

categoryRecommended Amount
Birth to 12 months10 mcg (400 IU)
Children 1–13 years15 mcg (600 IU)
Teens 14–18 years15 mcg (600 IU)
Adults 19–70 years15 mcg (600 IU)
Adults 71 years and older20 mcg (800 IU)
Pregnant and breastfeeding women15 mcg (600 IU)

Vitamin D testing and implications   

Vitamin D test is a blood test wherein the 25-hydroxyvitamin D form of vitamin D is measured because of its long half-life and higher concentration available in the blood. 

25-hydroxyvitamin D concentration is measured in both nanomoles per liter (nmol/L) and nanograms per milliliter (ng/mL) and 1 nmol/L = 0.4 ng/mL.

Concentration in ng/mLHealth status
<12Vitamin D deficient and may lead to diseases like osteomalacia, rickets 
12 to <20inadequate for bone and overall health in healthy individuals
≥20adequate for bone and overall health in healthy individuals
>50Linked to adverse effects in healthy individuals

Does vitamin D confer protection against the coronavirus?

Fact check:

  • According to a study published in The Lancet, vitamin D might help reduce the inflammatory response (cytokine storm) to SARS-CoV-2 infection, which is the most common cause of death in COVID 19 patients.
  • Vitamin D supports the production of antimicrobial peptides in the respiratory epithelium, thus making infection with the virus and development of COVID-19 symptoms less likely.
  • The study also showed that COVID-19 emerged and started its spread in the Northern hemisphere at the end of 2019 (winter) when levels of vitamin D are at their lowest. During this time, there was  greater disease burden and higher mortality.
  • The study also showed that in countries like Europe and Wales, dark-skinned individuals (who are at high risk for vitamin D deficiency) have more than four times the mortality rate than that of  light-skinned individuals.

So, should everyone start taking vitamin D supplements?

Despite the fact that vitamin D is crucial for many processes in the body, taking more amounts than required can have dangerous effects in the long run. It can lead to hypercalcemia. The risk of toxicity is higher in people with liver and kidney disease. So, based on the current levels of vitamin D  levels and the doctor’s recommendations, people can improve their Vitamin D levels by taking supplements or through diet.  

In addition to this, there is no scientific or clinical evidence that vitamin D can reduce the risk of getting infected with coronavirus.  

Like the study discussed earlier, it has been shown that the mortality rate and the number of COVID cases depend on a lot of factors like general health, the proportion of elderly people in a population, accessibility, and quality of healthcare, and socioeconomic status. It does not depend only on the vitamin D level.

However, according to medical experts and researchers, optimal levels of vitamin D can improve individuals’ health significantly. However, Vitamin D alone cannot prevent coronavirus infections. 

Findings from such studies are crucial for countries like India where most of the general public are vitamin D deficient. As the lockdown continues, most of the individuals are working from home which results in lesser exposure to the sun, which in turn results in vitamin D deficiency. So, people should consume vitamin D rich foods to compensate. 

Prevention and immunity are affected by multiple factors such as diet, sleep habits, stress levels, hygiene, genetics, etc. There is no nutrient or medicine which can be singled out for conferring protection against COVID 19. It is essential to continue following safety precautions and practices such as washing hands frequently, maintaining physical distance, wearing a mask, etc.

Disclaimer: The information provided here is not exhaustive by any means. Always consult your doctor or other qualified healthcare provider with any questions you may have regarding a medical condition, procedure, or treatment, whether it is a prescription medication, over-the-counter drug, vitamin, supplement, or herbal alternative.