Coronavirus Nutrition Tips – A Deeper Dive

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coronavirus covid 19 LJFaGuest blog by Lisa Jo Finstrom, MS, CNS, LDN. Lisa Jo is a nutritionist at Village Green Apothecary.

As a licensed nutritionist in the state of Maryland, I would like to share some basic tips on boosting the immune system, especially during the coronavirus crisis.

First of all, I’d like to clarify a few terms. The novel coronavirus we are dealing with is called SARS-CoV2, which stands for Severe Acute Respiratory Syndrome Coronavirus 2. The infectious disease we are trying to avoid is called COVID-19. I’m making this point of clarification for the sole purpose of emphasizing the danger posed to anyone with a history of respiratory issues.

Exposure to the coronavirus does not mean one is destined to get sick. One problem in the United States is that almost half of our adult population suffers from at least one underlying health condition, such as obesity, diabetes, high blood pressure, cardiovascular disease, kidney disease and autoimmune conditions, any one of which is thought to increase a person’s risk of contracting COVID-19.

At this point, it is believed that the coronavirus spreads through respiratory droplets produced by coughing or sneezing. The virus also sticks to surfaces for an indeterminate amount of time.

The median incubation period is 5-6 days. What makes this virus so pernicious is that it can be spread by asymptomatic individuals who do not feel sick. While the longest known incubation period was 24 days, 14 days is considered a safe amount of time to self-quarantine after potential contact with coronavirus carriers, both symptomatic and asymptomatic. (Williamson, 2020)

Typical COVID-19 symptoms include a fever, dry cough and shortness of breath. Other symptoms have also been reported.


Eat a mostly whole food diet rich in vegetables and fruit. Unfortunately, most people consume the Standard American Diet (SAD), which promotes obesity, chronic inflammation and a suppressed immune response. Highly processed carbs and sugary foods are often called “empty calories,” a neutral-sounding phrase when in fact these dead foods aggressively deplete the body of the very nutrients needed to maintain a robust immune response. To strengthen the immune system, say “yes” to salads, whole grains and fresh fruit, and “no” to cake, soda and fast food.


Supplementation can play an important role in immune system support, especially considering that on a daily basis many Americans eat a highly processed diet lacking in vitality, are exposed to environmental toxins, and have underlying health issues.

Vitamin C – Vitamin C is the fourth leading nutritional deficiency in the United States.

  • Pollution and smoking are known to deplete vitamin C, which is needed to run most aspects of the immune system. Research suggests vitamin C helps prevent and treat a wide variety of infections, including pneumonia. (Hemilia, 2017)
  • Adequate vitamin C levels in the body can enhance the all-important epithelial barrier function. Epithelial cells are the cells that line all surfaces of the body from the skin, to organs and blood vessels.
  • The body probably cannot absorb more than 500 mg of vitamin C at a time. Larger doses should be divided.
  • In China, there is reportedly an interest in the use of high dose vitamin C IV treatments for patients with severe COVID-19 pneumonia-like symptoms, with clinical trials in the works. (Lichtenstein, 2020)
  • Some hospitals in New York City have taken note of the use of vitamin C in China for coronavirus patients and are beginning to do the same. (Mongelli & Golding, 2020)

Vitamin D – Over a billion people worldwide have inadequate levels of vitamin D.

  • Those over 65, with dark skin, or low sun exposure are especially susceptible to vitamin D deficiency.
  • While vitamin D sufficiency is difficult to obtain by food alone, it is found in oily fish, pasture-raised eggs and liver. (Naeem, 2010)
  • Vitamin D is needed to protect mucosal cells, the kind of barrier cells that line the nose, as well as epithelial cells found in the lungs.
  • Maintaining adequate vitamin D levels can help protect the lungs.
  • For those with an already compromised respiratory system, it’s important to realize that “the protective effect of vitamin D supplementation against respiratory infections have been consistently demonstrated in susceptible populations.” (Wang, et al. 2019)

Vitamin A – Vitamin A deficiency is the leading cause of childhood blindness in the world. Vitamin A plays a critical role in warding off infections. Sadly, 44% of Americans don’t meet the estimated average requirement for this key vitamin. (Drake, 2010)

  • For years, vitamin A has been known as the “scary” vitamin because high levels can cause serious health problems, including birth defects in pregnant women.
  • However, insufficient vitamin A leaves us vulnerable to myriad health problems, including a higher risk of viral infections.
  • Adding to the confusion, there are three types of vitamin A – the kind found in animal sources (and most easily utilized by the body), synthetic forms, and a precursor form common to many brightly colored vegetables.
    1. Retinyl palmitate and acetyl are examples of synthetic forms of vitamin A. These are the forms found in most supplements and many processed foods as a substitute for animal-based “true” vitamin A. While many lives have inevitably been saved by the fortification of foods such as certain vegetable oils, breakfast cereals, and milk – for a small group of people, synthetic vitamin A can cause serious problems.
    2. True vitamin A is best obtained from animal sources, including eggs and meat, but especially liver.
    3. The precursor form of vitamin A includes the carotenoids such as carrots and sweet potatoes. Under the right conditions, these plant-based vitamin A precursors are converted into true vitamin A. Here is a partial list of common conditions that may impair the conversion of carotenoids into vitamin A:
      • Diabetes
      • Low-fat diets
      • Lack of gall bladder
      • Digestive issues
      • Consuming less than 4-5 servings of plant-based carotenoids daily (a serving is 1 cup raw or ½ cup cooked).
  • How to get true vitamin A?
    • Eat liver!
    • My favorite vitamin A supplement is made by Blue Bonnet and consists of 100% cod liver oil – not synthetic vitamin A.
    • Take cod liver oil – just as Mary Poppins famously gave the children in dreary London years ago. It now comes in lemony flavors, foregoing the need for a “spoonful of sugar.”
    • Eat lots of colorful veggies and don’t forget to pair them with high quality oils, like avocado, olive, butter and coconut to facilitate their conversion to vitamin A and to enhance absorption of other important nutrients. By the way, save your canola, corn and soy oils for the lubrication of squeaky doors – not for ingestion by humans, please!
  • Vitamin A is critically important to lung health and low levels of vitamin A are known to “disrupt normal lung physiology and predispose to severe tissue dysfunction and respiratory disease.” (Timoneda et al. 2018)

Vitamins D, K2 and A

  • They work together synergistically and ideally should be kept in balance.
  • Taking too much vitamin D can throw off vitamin A levels. I know this to be true because it happened to me. Several years ago, I was following the fad of taking a high dose of vitamin D. I neglected to pair it with vitamin A and when I got my micronutrient levels tested, my vitamin A levels were suboptimal.
  • Vitamin K2 is also a player, but I’m not going to get into any detail because it’s more known for supporting cardiovascular and bone health. In short, if you supplement with vitamin D (and doesn’t almost everyone?), consider taking vitamin K2 and A as well to keep them all in balance and playing nicely together.

Zinc – Zinc insufficiency is a global problem. In the US, those most susceptible to low levels include children, adolescents, the elderly, those with digestive illnesses such as Celiac, alcoholics and strict vegetarians. (Guilliams, 2014

  • Certain common medications can deplete zinc.
  • Zinc boosts the immune system.
  • Zinc maintains the senses of smell and taste.
  • A loss of a sense of smell and taste is said to be a one of many possible COVID-19 symptoms.
  • Zinc works synergistically with vitamins D, K2 and A.
  • Food-based sources of zinc include oysters, red meat, yogurt, chick peas and baked beans.
  • Currently, I’m taking a 15 mg zinc lozenge daily to cover my bases and provide extra immune support – especially for my mouth and throat.



  • I’m such a fan of elderberry that I planted some in my backyard and plan to make syrup in the fall.
  • I take a swig of elderberry syrup daily.
  • There is evidence that elderberry may help prevent viral replication in certain flu and coronavirus infections. (Chen, et al. 2014)
  • Elderberry is well tolerated by most people.


  • Is used in many anti-viral supplement formulas.
  • May be effective against flu strains.
  • May interact with certain medications.
  • Should be avoided for long-term, daily use.
  • May be most effective at immediate onset of an infection. (Pleschka, et al. 2009)

Medicinal Mushrooms

  • Contain numerous health-promoting constituents, including beta-glucans.
  • Have been used to support the immune system for thousands of years.
  • Help increase T cells and macrophages. (Akramiene, et al. 2007)
  • A macrophage is like a Pac-Man that gobbles up the bad guys, including viruses, fungi, bacteria and parasites.
  • Note: some mushrooms can be poisonous.


  • Lemons
  • Green tea
  • Garlic – raw only (Bayan, et al. 2014)
  • Culinary mushrooms, such as shitake
  • Liver – while I’ve not seen it on any list of anti-viral foods, I’m adding it due to the fact it is a storehouse of vitamins D and vitamin A.


  • Let’s not forget that our gut is key to our immune system. After all, with every bite we eat, it’s the gut that must determine friend from foe. It’s the gut that contains stomach acid strong enough to literally burn up pathogens.
  • What we eat helps determine the robustness of our gut microbiome and its ability to protect us from pathogens. (Williamson, 2020)
  • Health-promoting microorganisms tend to thrive if fed a diet rich in whole foods, including a wide variety of veggies, fruit and sufficient fiber.
  • For many people, fermented foods such as sauerkraut, miso, kombucha, pickles and yogurt can help maintain the health of the gut microbiome.
  • Sugar, poor quality cooking oils, factory-farmed meat, processed foods, and insufficient veggie intake tend to encourage the “weeds” or bad microbes to thrive, thus pushing out the good microbes that help keep us healthy – much like an untended garden.

MUCOLYTICS – These are used to break up mucus once it starts to impede ease of breathing.

  • Guaifenesin – the active ingredient in Mucinex.
  • NAC, also known as n-acetylcysteine, an amino acid, is available as a supplement.
    • Take on an empty stomach.
    • There is considerable evidence that it helps break up the mucus.
    • It’s been used with patients with COPD and other serious respiratory diseases, including asthma. (Sadowska, 2006)
    • I keep NAC on hand, just in case.

HYDRATION – Sip on pure water and herbal tea throughout the day!

  • Dehydration is common at all ages, but especially amongst the elderly who lose the sensation of thirst or wish to avoid nighttime trips to the bathroom.
  • The main component of blood is water, and the main job of blood is to transport nutrients to every cell in the body.
  • Water also helps the lymphatic system drain pathogens from the body.
  • When you feel under-the-weather, sipping on warm tea helps to wash pathogens, including viruses, down the throat and into the stomach, where robust stomach acid will attack and hopefully destroy pathogens.

Family Friendly Recipe:
Roasted Cauliflower with Garlic Yogurt Sauce

Preheat oven to 425 degrees. Cut up 1-2 heads of cauliflower into flowerets and coat with a healthy oil with a high smoke point, such as avocado oil (no flavor) or coconut oil (always on sale at Trader Joe’s). Add salt and pepper and roast until brown on the edges, at least 15 to 20 minutes.

Prepare the yogurt sauce: Use a cup of full fat, unflavored yogurt – either dairy or coconut (you could substitute sour cream in a pinch). Finely dice 4-6 cloves of fresh garlic and add to the yogurt. Add juice of one entire lemon, zest of one lemon, 2-3 tablespoons olive oil, salt and pepper. Add a smear of yogurt sauce to the plate and top with roasted cauliflower.

Note to Vegetarians

While I am very sympathetic to those those who avoid animal products for religious, cultural or environmental reasons, for most people, a strict vegan diet puts them at a higher risk of certain nutritional deficiencies, including the above-mentioned vitamins D and A, and sometimes zinc. That being said, when I’ve tested vegan clients for micronutrient deficiencies, I am often pleasantly surprised at how well they are doing in spite of dietary restrictions. Personally, I can’t call myself a vegetarian because, while I prepare lots of vegetarian meals at home, I also eat eggs, dairy, fish, and the occasional bone broth and liver.

Lastly, I’d note that ethically sourced animals, i.e., animals that have lived their whole lives outdoors eating the foods that nature intended for them to eat, are much healthier for humans than the animals raised in indoor factories. A pasture-raised animal has a nutritional profile far superior to a factory-raised animal and therefore is less likely to promote inflammation and other health issues.

Lisa Jo Finstrom, MS, CNS, LDN, is a nutritionist at Village Green Apothecary, and the owner of Common Sense Nutrition, LLC. Learn more about her, or book a consultation, on Village Green’s practitioner page.

Disclaimer: Statements made in this article have not been evaluated by the United States Food and Drug Administration and are not intended to diagnose, treat, cure or prevent disease. The information provided is for informational purposes only and is not intended as a substitute for advice from your physician or health care professional.


Akramierna D., Kondrotas A., Didziapetriene J. & E. Kevelaitis (2007) Effects of B-glucans on the immune system. Medicina (Kaunas) 43(8). Retrieved from

Bayan, L., Koulivand, P. H., & Gorji, A. (2014). Garlic: a review of potential therapeutic effects. Avicenna journal of phytomedicine, 4(1), 1–14.

Chen, C., Zuckerman, D. M., Brantley, S., Sharpe, M., Childress, K., Hoiczyk, E., & Pendleton, A. R. (2014). Sambucus nigra extracts inhibit infectious bronchitis virus at an early point during replication. BMC veterinary research, 10, 24.

Hemilä H. (2017). Vitamin C and Infections. Nutrients, 9(4), 339.

Lichenstein, K., 2020. Can vitamin c prevent and treat coronavirus? Retrieved 3/9/2020 from

Mongelli L & B Golding. (2020) New York hospitals treating coronavirus patients with vitamin C Retrieved March 24

Naeem Z. (2010). Vitamin d deficiency- an ignored epidemic. International journal of health sciences, 4(1), V–VI. Retrieved from

Pleschka, S., Stein, M., Schoop, R., & Hudson, J. B. (2009). Anti-viral properties and mode of action of standardized Echinacea purpurea extract against highly pathogenic avian influenza virus (H5N1, H7N7) and swine-origin H1N1 (S-OIV). Virology journal, 6, 197.

Sadowska, A. M., Verbraecken, J., Darquennes, K., & De Backer, W. A. (2006). Role of N-acetylcysteine in the management of COPD. International journal of chronic obstructive pulmonary disease, 1(4), 425–434.

Timoneda, J., Rodríguez-Fernández, L., Zaragozá, R., Marín, M. P., Cabezuelo, M. T., Torres, L., Viña, J. R., & Barber, T. (2018). Vitamin A Deficiency and the Lung. Nutrients, 10(9), 1132.

Williamson, C. (2020) Nutritional Genomics Institute. Retrieved from

Wang, M. X., Koh, J., & Pang, J. (2019). Association between micronutrient deficiency and acute respiratory infections in healthy adults: a systematic review of observational studies. Nutrition journal, 18(1), 80.

Photo from here, with thanks.

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