COVID-19 & Vitamin D

The abundance of misinformation out there regarding COVID-19 and nutrition is alarming. While these pieces mainly revolve around “boosting” one’s immunity, some go as far as claiming that certain nutrients prevent or treat this virus. I have been wanting to write a science-based article that compiles truths and telephone-game rewrites of how nutrition impacts this virus and its hosts. **SPOILER ALERT** Some of it is true!!

The top nutrients in relation to COVID-19 will be discussed post by post over the next week, as one post would have been way too¬†lengthy to cover everything I wanted to. Today’s topic is vitamin D.

Vitamin D

Vitamin D is a fat-soluble vitamin, meaning, it is dissolvable in lipids (fat) and stored in the liver and fatty tissues. We can obtain vitamin D from the sun (of which our skin converts and transfer it to our liver then kidneys to be activated), or from dietary sources.

Dietary sources of vitamin D include:

  • Fish (such as salmon, tuna, herring, cod and sardines)
  • Egg yolks
  • Beef liver
  • Cheese
  • Mushrooms
  • Fortified foods and beverages (such as cow’s milk, yogurt, soy milk, plant-based milk, orange juice, and cereals)

The functions of this vitamin include:

  • Calcium homeostasis
  • Bone health (aids in calcium absorption)
  • Cell differentiation
  • Cell growth, maturation, and reproduction
  • Modulation of innate and adaptive immune responses¬Ļ

Let’s start with those who are vitamin D deficient. According to the Journal of Investigative Medicine, “Individuals with lower vitamin D levels (<30 nmol/L) were more likely to self-report a recent upper respiratory tract infection than those with sufficient levels, even after adjusting for variables including season, age, gender, body mass and race”. This is because both the risk and development of SARS, or Severe Acute Respiratory Syndrome, is associated with lower serum vitamin D levels.¬†The risk is attributed to vitamin D increasing¬†“cathelicidins and defensins that can lower viral replication rates and [reduce] concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs”.¬Ļ

From 2005-2006, the Nutrition Examination Survey found that 41.6% of Americans were vitamin D deficient.² This is a significant number, especially with the current risk of contracting the highly transmissible COVID-19 strain. Since many of us are still under a stay-at-home order and may not be getting enough sun, I highly recommend trying to either consume more foods that contain vitamin D (listed above) or to invest in a vitamin D3 supplement.

The National Institute of Health recommends daily doses of 600-800 IUs. Many supplements are higher than this, but due to the risk of hypercalcemia, calcification of soft tissues, and other side effects, it is not recommended to exceed 4,000 IUs/day.³ Although studies are currently looking at higher dosing for prevention and treatment, individuals should not attempt this at home.

It may take 2-4 weeks for vitamin D to accumulate to sufficient amounts in your system, so you may lower your dosage once you get back in the sun more often or ensure your levels are where they should be. A multivitamin with vitamin D can do the trick too.

The first bullet is where you want your numbers to be.

* Vitamin D sufficiency: Serum 25OHD 50-125 nmol/L (20-50 ng/mL)

* Vitamin D inadequacy: Serum 25OHD 30-49 nmol/L (12-19 ng/mL)

* Vitamin D deficiency: Serum 25OHD less than 30 nmol/L (12 ng/mL)³

You can get your levels checked in a routine biochemical lab panel from a blood draw. Contact your primary care physician to make an appointment.

But what about vitamin D treating those infected with COVID-19? 

While vitamin D reduces the risk of developing an infection, it does not guarantee protection or immunity from this virus. Nor has it been proven to treat or cure COVID-19.   I will leave you with this- vitamin D and vitamin C are strongly linked to improved immune responses. You can ensure your levels are where they need to be through consuming dietary sources or by supplementation, followed by getting bloodwork done.

However, “boosting your immune system” shouldn’t be a coined health phrase because we should always want to enforce our immune strength. This can be done by eating a well-balanced diet, scheduling regular wellness checkups with bloodwork and labs, and by taking supplements and/or a multivitamin.

Did I answer our questions about vitamin D in relation to COVID? Drop me a comment on what you thought!

The medical/health information is provided for general informational and educational purposes only and is not a substitute for professional advice. Accordingly, before taking any actions based upon such information, we encourage you to consult with the appropriate professionals. We do not provide any kind of medical/health advice. THE USE OR RELIANCE OF ANY INFORMATION CONTAINED ON THIS SITE OR OUR MOBILE APPLICATION IS SOLELY AT YOUR OWN RISK.

Photo by Michele Blackwell on Unsplash


1. Aranow C. Vitamin D and the Immune System. Journal of Investigative Medicine. 2011;59(6):881-886. doi:10.2310/jim.0b013e31821b8755
2. Parva NR, Tadepalli S, Singh P, et al. Prevalence of Vitamin D Deficiency and Associated Risk Factors in the US Population (2011-2012). Cureus. May 2018. doi:10.7759/cureus.2741
3. Office of Dietary Supplements РVitamin D. NIH Office of Dietary Supplements. Accessed May 18, 2020.

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