Supporting the Immune System During COVID-19

I frequently receive questions from my patients about what supplements they can take to help prevent COVID 19. While we don’t have anything available to PREVENT this virus, there are supplements that one can take to help support the immune system and therefore help fight off potential infection.

There are no robust studies ongoing to determine if some supplements available will help reduce the risk of contracting COVID 19 and it’s important to understand that no supplement, diet, or other lifestyle modification other than physical distancing, also known as social distancing, and proper hygiene practices, including mask-wearing, frequent hand washing or use of hand sanitizer, can protect you from COVID-19.

However, it is still key to do what you can to support your immune system during this pandemic.


Zinc is important for immune function. It plays a role in the production of antibodies and white blood cell that help fight infections. Zinc deficiency increases inflammation and decreases the production of antibodies. High-dose zinc has also been found to reduce the duration of symptoms of the common cold. It is not yet clear whether zinc supplementation benefits patients with lower respiratory tract infections such as COVID-19. Because of its role in immune function and potential to decrease coronavirus replication, zinc is currently being investigated for the treatment of patients with COVID-19.

I recommend 30-50 mg of Zinc daily. It is available in caps or lozenges. It also comes in the form of a throat spray. Please do not use zinc throat sprays in the nose as I have had two patients who have lost their sense of smell after using zinc nasally. The Zicam nasal swabs are now a zinc-free homeopathic treatment after many reports of anosmia, the loss of sense of smell, when the product contained zinc.

A couple of brand options for zinc supplements include Garden of Life Vitamin Code Raw Zinc and Life Extension Zinc Caps.

Vitamin D

Vitamin D deficiency is common, due to lack of sun exposure, older age, corticosteroid use and darker skin. All are factors that are associated with lower concentrations of 25-hydroxyvitamin D. A higher incidence of acute respiratory infections is associated with vitamin D deficiency. Additionally, a link between seasonal influenza and vitamin D deficiency has been hypothesized. Vitamin D supplementation has also been shown to decrease the incidence of acute respiratory infection. While taking Vitamin D has yet to be studied for prevention of COVID-19 infection, some recent articles have recommended taking daily supplements to raise 25-hydroxyvitamin D concentrations to reduce infection risk.

I check Vitamin D levels on all of my patients and the vast majority are Vitamin D deficient when not supplementing the nutrient. If you have not had your blood level checked, I recommend taking Vitamin D3 1000 iu (25mcg) to 2000 iu (50 mcg) once daily and asking your provider to check this level at your next appointment. There is prescription Vitamin D2 available in a 50,000 iu once weekly dosing, but Vitamin D3 is the preferred form of supplementation. There is an over the counter 50,000 iu cap of Vitamin D3 available, but I do not recommend this dosing unless you have had a blood test to check your level and have been advised by a medical professional to take high dose vitamin D replacement. Most of my patients require 5000 iu daily based on lab work.

Again, Garden of Life Vitamin Code has a Raw D3 in 2000 iu and 5000 iu caps, a 2000 iu chewable, vegan D3 and an organic D3 spray 1000 iu per spray.

Vitamin C

Vitamin C, or ascorbic acid, is an antioxidant and a number of studies suggest that vitamin C supplementation impacts the immune system by supporting the function of various immune cells and enhancing their ability to protect against infection. It’s also necessary for cellular death, which helps keep your immune system healthy by clearing out old cells and replacing them with new ones.

Studies in birds have shown that vitamin C might protect against avian coronavirus infection, with human trials finding that vitamin C may decrease susceptibility to viral respiratory infections and pneumonia.

New clinical trials are underway in China and the United States to determine if vitamin C might be used as a treatment for COVID-19.

I recommend dosing Vitamin C 500 mg twice daily. Garden of Life Raw Vitamin C contains 500 mg of Vitamin C and probiotics and gastric enzymes to help absorption.


N-acetylcysteine converts to glutathione, which is an antioxidant that becomes depleted when oxidative stress or systemic inflammation is present. Administering this supplement provides anti-inflammatory and antioxidant effects in a number of pulmonary diseases, including viral pneumonia and acute respiratory distress syndrome. Because patients with COVID-19 have evidence of systemic inflammation, often have their course complicated by acute respiratory distress syndrome, and may have respiratory mucus buildup limiting adequate airflow, systemic or aerosolized N-acetylcysteine (or both) may be beneficial in this specific patient population. Aerosolized NAC is a prescription medication that is used for treatment of pulmonary disease, not a supplement option that is being discussed here.

NAC dosing is 600 mg once daily. Life Extension makes an NAC 600 mg cap, but there are many other brands available.


Black elderberry , which has long been used to treat infections, is being researched for its effects on immune health.

Elderberry extract, in test tube studies, demonstrates potent antibacterial and antiviral potential against pathogens responsible for upper respiratory tract infections and against influenza virus strains.

Additionally, it enhances immune system response and may help shorten the duration and severity of colds, as well as reduce symptoms related to viral infections.

Although it was a small study, a review of 4 randomized control studies in 180 people found that elderberry supplements significantly reduced upper respiratory symptoms caused by viral infections.

Elderberry supplements are most often sold in liquid or capsule form. Gaia Herbs has an Elderberry Gummy with standard dosing of 2 gummies daily. They also offer Elderberry Syrup 1 teaspoon daily and Elderberry Caps one cap twice daily.

You do not have to take all of these supplements, but the combinations of these supplements is a good little immune support package!

Blood Typing

Unrelated to the supplement recommendations, I have also received MANY requests from patients to look in their chart and tell them their blood type. This has come up because there has been much discussion in the media about blood type and risk of COVID infection. This testing is NOT routinely done in the primary care office for a couple of reasons. First of all, if you need blood products in the hospital, they will check your blood type just prior to administration of those products. They are not going to rely on you telling them your blood type, a mistake would be disastrous . Secondly, insurance coverage for the test is spotty. The only type of medical practice that routinely checks blood type is an obstetrics office because that information is needed for the appropriate care for the mother and baby.

You can always request that the testing be done at your primary care office but you may be asked to sign a waiver stating that you will pay for the test if your insurance does not. Other ways to get that information is to either donate blood or use a simple home test kit like the one from D’Adamo for $9.95.

The research to determine a possible relationship between blood types and risk of COVID infections and complications began in March, 2020 in China. They observed that people with Type A blood appeared to be at significantly higher risk of contracting the virus. The risk for individuals for Type O blood appeared to be significantly lower. Individuals with Type A blood type also represented a higher percentage of patients who succumbed to the illness — 41 percent versus 25 percent for Type O.

In April, researchers at Columbia University reported similar risks associated with Type A blood after blood-typing more than 1,500 New Yorkers and testing them for COVID-19. 

Researchers in Italy and Spain,  like the researchers in China and New York City, found a higher risk for severe illness among individuals with Type A blood and a protective effect for Type O.

Type A blood was associated with a 45 percent increased risk of having respiratory failure, while Type O was associated with a 35 percent reduction in risk.

Of course, your blood type is something you cannot control. So please don’t panic if you have Type A blood, and please don’t feel complacent if you’re Type O. What we DO have control over is how we live our lives. So, keep wearing that mask, socially distancing, and washing your hands. We KNOW these actions will help reduce our risk of COVID 19 infection. As a reminder, the following are recommendations from the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) to prevent COVID 19 infection:

  • Avoid large events and mass gatherings.
  • Avoid close contact (within about 6 feet, or 2 meters) with anyone who is sick or has symptoms.
  • Stay home as much as possible and keep distance between yourself and others (within about 6 feet, or 2 meters), especially if COVID-19 is spreading in your community, especially if you have a higher risk of serious illness. Keep in mind some people may have COVID-19 and spread it to others, even if they don’t have symptoms or don’t know they have COVID-19.
  • Wash your hands often with soap and water for at least 20 seconds, or use an alcohol-based hand sanitizer that contains at least 60% alcohol.
  • Cover your face with a cloth face covering in public spaces, such as the grocery store, where it’s difficult to avoid close contact with others. Only nonmedical cloth masks — surgical masks and N95 respirators should be reserved for health care providers.
  • Cover your mouth and nose with your elbow or a tissue when you cough or sneeze. Throw away the used tissue and wash your hands or use hand sanitizer.
  • Avoid touching your eyes, nose and mouth.
  • Avoid sharing dishes, glasses, bedding and other household items if you’re sick.
  • Clean and disinfect high-touch surfaces daily.
  • Stay home from work, school and public areas if you’re sick, unless you’re going to get medical care. Avoid taking public transportation if you’re sick.
  • Before traveling, check the CDC and WHO websites to look for health advisories that may be in place.

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