COVID-19 & Vitamin C

Moving on to another hot topic regarding COVID and nutrition- today I’m telling all about vitamin C! Nope, not the infamous graduation song singer. The vitamin. (bad joke, I know). 😉

Vitamin C

Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that is utilized primarily as an antioxidant. Antioxidants fight free radicals, toxins and stress that oxidize and damage cellular function. Vitamin C is considered an essential micronutrient because our bodies don’t produce it. Instead, we must rely on our diet or oral supplementation for our daily dose.

Dietary sources of vitamin C:

  • Citrus fruits (such as lemons, limes, grapefruit, and oranges)
  •  Berries
  • Papaya
  • Potatoes
  • Tomatoes
  • Peppers
  • Cabbage
  • Brussel sprouts
  • Broccoli
  • Spinach¹

*If you are not consuming enough of these foods, a multivitamin should do the trick. The DRI (Daily Recommended Intake) for men is 90 mg, while the DRI for women is 75 mg.¹ Just double check your multi-vit label.

Many of us have heard to take vitamin C when we feel like we’re coming down with something. Whether it’s drinking OJ or chugging Emergen-C, this is luckily a common knowledge remedy. And it’s true! Science has shown that vitamin C consumption does work as a weak antihistamine, relieving flu and cold-like symptoms like sneezing, a runny nose, and congestion or swollen nasal cavities.² But vitamin C does much more than fight off foreign invaders…

The functions of this vitamin include:

  • Acts as an antioxidant
  • “Recharges” enzymes
  • Collagen synthesis
  • Precursor to hormone production and secretion
  • Needed for formation of blood vessels, cartilage, and muscles
  • Essential for wound healing
  • Neurotransmitter
  • Hormone synthesis
  • Aids in iron absorption and storage
  • Anti-carcinogen
  • Protects against heart disease¹

As far as COVID prevention is concerned…

Different studies showed that ascorbic acid (vitaminC) positively affects the development and maturation of T-lymphocytes, in particular NK (Natural Killer) cells involved in the immune response to viral agents. It also contributes to the inhibition of ROS production and to the remodulation of the cytokine network typical of systemic inflammatory syndrome.²

While vitamin C cannot outright prevent contracting COVID-19, it has a significant influence on how your immune system responds to and fights the virus cells if you do become infected.

The classic symptoms of COVID-19 thus far are fever, coughing, and shortness of breath, a myriad of other signs and symptoms have been reported around the world. According to the CDC, these symptoms include, but are not limited to chills, muscle pain, sore throat, and loss of taste and smell. Critical illness complications are not typically discussed, but The National Institute of Health has an entire page on these, two relative conditions being sepsis and pneumonia.

Septic shock develops due to an infection. It displays itself as low blood pressure and organ failure. “It is estimated that 40% of critically ill patients with septic shock have serum vitamin C levels that suggest scurvy (<11.3 μmol/l).” Therefore, vitamin C supplementation could be beneficial for this group.²

But what does this have to do with COVID? Good question. COVID-19 is a viral strain that causes an upper and/or lower respiratory infection, among other signs and symptoms. Sepsis develops due to infection, so it is quite possible for COVID patients who are in critical condition can develop sepsis and display vitamin C deficiency.

The University of Palermo in Sicily, Italy has decided to treat their COVID patients by administering 10 grams of vitamin C in 250 ml of saline to infuse at a rate of 60 drops/minute. This was decided after a preliminary double-blind study was conducted on 167 patients with Acute Respiratory Distress Syndrome back in October of 2019. The trial treated randomized patients with COVID pneumonia with 50 mg/kg every 6 h of high dose intravenous vitamin C (HDIVC) for 4 days versus placebo. By day 28, 46.3% of the placebo cases resulted in fatal conclusions, while 29.8% represented the mortality rate for those treated with vitamin C.² Those treated with vitamin C had a 36% lower rate of mortality.

Other studies have implemented similar doses with the addition of a glucocorticoid to fight inflammation and carb-restricted diet (usually parenterally administered, or through an IV).³

Vitamin C Supplementation Risks

Vitamin C toxicity is unlikely because it is not stored in the body; however excessive vitamin C dosing can lead to cramping, diarrhea, nausea, and even kidney stones in some long-term cases.

Possible food and drug interactions include the following:

  • Aluminum, found in phosphate binders, that could be harmful to dialysis patients
  • Chemotherapy
  • Estrogen
  • Protease inhibitors
  • Statins and niacin
  • Warfarin (aka Coumadin)¹

*Please consult with your physician before taking vitamin C.


While vitamin C has traditionally been used to ward off the onset of mild cold and flu symptoms, it has not been proven to prevent contracting COVID-19. However, vitamin C has been shown to increase the amount of T-lymphocytes and Natural Killer cells, which both assist the innate immune system in attacking viral-infected cells. Vitamin C also attenuates oxidative stress and inflammation. Lastly, in terms of prevention, this powerhouse helps modulate cell signaling by improving cytokine (hormone-like protein involved in the immune response) production and function.

Further studies are currently underway in the midst of this global pandemic, with many hospitals actively treating their COVID patients intravenously with vitamin C along with other biomedical treatments. So far, the results indicate that vitamin C can lower mortality rates for critically-ill patients.

Does this mean that you should dose with vitamin C? Nope! While it doesn’t hurt in suggested amounts, you can simply incorporate more foods and beverages that contain vitamin C or get your daily fix through a multivitamin.

Photo by Bruna Branco on Unsplash


  1. Vitamin C. Mayo Clinic. Published October 18, 2017. Accessed May 20, 2020.
  2. Rossetti CA, Real JP, Palma SD. High Dose Of Ascorbic Acid Used In Sars Covid-19 Treatment: Scientific And Clinical Support For Its Therapeutic Implementation. Ars Pharmaceutica. 2020;61(2):145-148. doi:
  3. Erol A. High-dose intravenous vitamin C treatment for COVID-19. Erol Project Development House for the disorders of energy metabolism. 2020. doi:10.31219/

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