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Nutrition for Supporting Antiviral Immunity

March 18, 2020 / Lindsay Christensen, MS, CNS, LDN

IN THIS ARTICLE:

  1. What Is COVID-19?

  2. How Does the Immune System Respond to COVID-19?

  3. Nutrition for Antiviral Immunity

  4. Functional Foods and Nutraceuticals with Antiviral Properties

  5. Micronutrients for Antiviral Immunity

  6. Botanicals with Immune-Supporting Properties


It is normal to feel overwhelmed during a pandemic as alarming as COVID-19. However, there is no need to feel helpless. There are many steps you can take to support your immune system, and that of your loved ones, during this challenging time.

First, I recommend following practical recommendations for reducing your risk of contracting COVID-19, and of spreading it to others.

Since many medical professionals have already adequately summed up these steps, I will not reiterate them here. Instead, I will direct you to an excellent website, https://www.flattenthecurve.com/, where you will find a comprehensive summary of the practical steps you can take to reduce your risk of contracting and spreading COVID-19. However, what I will do is add on to the existing risk-reduction discussion by talking about my area of expertise – nutrition – and how you can optimize these factors to support your immune system. In part two of this two-part blog series, I will discuss lifestyle practices that can help your immune system against viral threats. However, before I dive into a discussion of nutrition and antiviral immunity, I would like to provide a brief summary of COVID-19, including what it is and how it impacts the body.

***Please note that I am not claiming any of the nutritional or botanical interventions listed here will cure COVID-19; rather, I am presenting the scientific research on how nutrition can support your immune system, increasing your likelihood of staying well during this pandemic.

What Is COVID-19?

COVID-19 is caused by SARS-CoV-2, a novel form of a coronavirus. COVID-19 stands for “coronavirus disease 19.” Coronaviruses are enveloped positive-sense viruses, which means they contain genetic material (in this case, RNA) that can be directly translated into viral proteins. The name “corona” means “crown,” in reference to the array of club-like spikes that project from their surface.

Coronaviruses are zoonotic, meaning they originate in animals and are subsequently transferred to humans, often by human consumption of an infected animal. COVID-19 appears to have originated in a food market in Wuhan, China. It is closely related to Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Middle Eastern Respiratory Syndrome Coronavirus (MERS-CoV).

How Does the Immune System Respond to COVID-19?

The innate immune system is the first line of defense against viral invaders.

It consists of:

  • Physical barriers: The skin, mucosa of the lungs, and intestinal mucosa

  • Biochemical mechanisms, such as gastric acid in the stomach

  • The inflammatory response

  • The complement system, a branch of the immune system

  • Phagocytes, a type of white blood cell that uses a process called phagocytosis to engulf foreign substances such as bacteria and viruses

The adaptive immune system comes in next, producing antibodies to the virus. The adaptive immune system consists of B cells, T cells, and immunoglobulins that facilitate a slowly acquired immunity against the virus.

Research indicates that specific micronutrients, foods, and lifestyle practices efficiently support the innate and adaptive immune systems in their response to viral invaders. Let’s discuss each of these interventions in turn.

Nutrition for Antiviral Immunity

The first step in supporting your immune system is to optimize your diet. I recommend that you avoid processed and refined foods, as these create an inflammatory burden in the body that distracts your immune cells from imminent infectious threats, such as those posed by COVID-19.

Instead, eat a diet composed of whole, nutrient-dense foods. I recommend following a Paleo template diet, which includes the following:

  • Non-starchy vegetables: Eat at least 3-4 servings of non-starchy vegetables per day. I recommend focusing mainly on cruciferous vegetables, which contain phytochemicals that support glutathione production. Glutathione is a critical molecule in the body’s antiviral defense system. (1)

  • Nutrient-dense carbohydrates: Many nutrient-dense carbohydrates are excellent sources of prebiotic fibers, which feed the beneficial bacteria in our guts that help support our immunity. Choose nutrient-dense starches such as sweet potatoes, winter squash, plantain, cassava, and taro. Include soaked and sprouted or fermented legumes and gluten-free grains, if you tolerate them.

  • Bioavailable Protein: As I discussed in my recent guest blog for Chris Kresser, Animal Protein and a Whole-Foods Diet: What the Science Says, animal foods such as meat and dairy are the most bioavailable source of dietary protein. A sufficient intake of bioavailable protein is essential for supporting muscle mass, which plays a critical role in immune function. (2) Choose proteins such as grass-fed beef and bison, pastured poultry, eggs, and wild-caught seafood. If you tolerate dairy, consider including full-fat, pastured dairy products, which are good sources of immune-supportive vitamin A and vitamin D.

  • Whole fruit: Berries are particularly rich in polyphenols, some of which have demonstrated antiviral properties. (3) My favorites are blueberries, blackberries, and raspberries. Wild berries are higher in bioactive polyphenols than domestic varieties, so you might also consider including lingonberries and huckleberries.

  • Healthy fats: Include plenty of healthy fats such as extra virgin olive oil, olives, avocado, avocado oil, fresh nuts and seeds, coconut, ghee, grass-fed butter, and wild-caught seafood.

  • Fermented foods: Fermented foods, such as sauerkraut and yogurt, are rich in probiotics with immune-boosting and antiviral properties. (4)

Functional Foods and Nutraceuticals with Antiviral Properties

There are several foods with particularly potent antiviral properties that I recommend you include in your daily diet during this time.

Bovine Colostrum

Colostrum is the first milk that comes from a cow after she has given birth to a calf. It is rich in bioactive compounds such as lactoferrin and immunoglobulins that establish a robust immune system in the calf and, fascinatingly, can also support our own immune systems! Studies indicate that bovine colostrum immunoglobulins offer antiviral activity against the influenza virus and are useful in the prophylaxis of upper respiratory tract infections. (5, 6)

The brand of colostrum I recommend is Sovereign Laboratories Colostrum-LD. The reason I suggest it is because it is liposomal, meaning the colostrum molecules are packaged in tiny lipid-based molecules that significantly enhance their bioavailability in the body. I’ve used this brand with several of my nutrition clients (and myself!) and have found it to be well-tolerated even by people with sensitivities to dairy products.

Propolis

Propolis is also known as “bee glue;” it is a resinous substance that bees use to protect their hive from pathogens. In animals and humans, propolis offers potent antiviral and immune-boosting activities. (7) I recommend it as a prophylactic treatment against viral infections.

Beekeeper’s Naturals offers a propolis throat spray and propolis-infused honey. I recommend spraying the propolis throat spray into the back of your throat several times a day and incorporating the propolis-infused honey into an herbal tea made with antiviral herbs, such as ginger. Ginger (Zingiber officinale) has antiviral activity against the respiratory syncytial virus (RSV) in human respiratory tract cell lines and inhibits the growth of the influenza virus. (8, 9) If you choose to use Traditional Medicinals ginger tea, which I’ve linked to here, use three tea bags to make a strong tea; research shows that high doses of ginger are needed to experience its antiviral benefits. You can also make fresh ginger juice, which is exceptionally potent, as Stephen Harrod Buhner suggests in his excellent book, Herbal Antivirals: Natural Remedies for Emerging & Resistant Viral Infections.

Green Tea

I was already a green tea lover well before COVID-19 hit, so I was excited to learn that a compound in green tea called EGCG offers antiviral properties! (10) If you want to include green tea in your antiviral routine, be sure to choose an organic brand of green tea that comes in a paper or compostable tea bag; avoid tea bags made with plastic, as these have been found to release microplastics into hot water (11), and microplastics may have detrimental effects on immune function. I am a fan of Pique Tea’s green tea varieties because they test their tea for mycotoxins and other contaminants and offer a super clean, delicious, health-enhancing tea!

Elderberry

Elderberry (Sambucus nigra) has been used for hundreds of years as an aid to the immune system. Elderberries are rich in anthocyanins with antiviral properties; however, elderberry balances the immune response to viral threats, preventing excessive virus-induced inflammation. (12, 13) The traditional way to consume elderberry is in syrup, such as Gaia Black Elderberry Syrup.

Sulforaphane

Cruciferous vegetables contain a sulfur-based phytochemical called glucoraphanin, which is converted to the phytochemical sulforaphane when the vegetables are cut or chewed and subsequently acted on by an enzyme in their cells called myrosinase. Sulforaphane is my favorite phytochemical for many reasons!

  • Sulforaphane activates the Nrf2 signaling pathway, which culminates in the production of glutathione. As I mentioned earlier, glutathione is a necessary molecule for antiviral immunity, among many other processes. (14)

  • Sulforaphane reduces inflammation, including lung inflammation. It is implicated as a possible therapeutic agent against neutrophilic airway inflammation. (15)

  • Sulforaphane has antiviral effects against influenza virus and respiratory syncytial virus. (16, 17)

My favorite way to get sulforaphane into my diet and my clients’ diets is by growing organic broccoli sprouts. (18) Broccoli sprouts are the most abundant dietary source of glucoraphanin and, subsequently, sulforaphane. However, if you don’t have the time or energy to grow your own broccoli sprouts right now, consider trying the stabilized, potent sulforaphane supplement BrocElite.

Kimchi

Fermented foods are rich in probiotic bacteria, which help support the immune system in your gut. Kimchi, a traditional Korean fermented vegetable dish, may be an especially crucial fermented food to include in your current diet! A fascinating study found that Lactobacillus plantarum, a probiotic found in kimchi, has pronounced antiviral activity against the H1N1 virus. (19) I suggest running over to your nearest health food store and picking up a jar of raw, organic kimchi today! Alternatively, you can make your own kimchi at home using a recipe such as this one.

Coconut Oil and Coconut Derivatives

Coconut oil is rich in lauric acid and its derivative, monolaurin. These compounds have demonstrated significant antiviral activity in previous research and have recently been suggested as possible therapeutics against COVID-19. (20) Incorporate organic, unrefined coconut oil into your daily diet and, if you feel yourself getting sick, consider supplementing with Lauricidin, a concentrated form of monolaurin.

Micronutrients for Antiviral Immunity

The innate and adaptive branches of your immune system require specific micronutrients to function correctly. Ensuring an optimal status of the following nutrients will set you on the path towards robust immunity and resilient health not only throughout our current COVID-19 challenge but throughout your life!

Vitamin A

Pre-formed vitamin A, also known as retinol, is essential for healthy immune function. It maintains the integrity of mucosal barriers, including those in the lungs and gut. Vitamin A is also crucial for the regulation of inflammation, T-cell proliferation and differentiation, cell-mediated immunity, and antibody production. (21) Importantly, pre-formed vitamin A is NOT the same as beta-carotene. Beta-carotene can be converted into vitamin A but is not done so efficiently in many people (especially people of European descent who historically consumed plentiful pre-formed vitamin A in their traditional foods, such as fatty cold-water fish).

The best dietary sources of pre-formed vitamin A include beef liver, pastured egg yolks, seafood (especially wild salmon), and full-fat dairy products from pastured cows. If you feel like you are coming down with an infectious illness, I recommend doing a short-term high-dose vitamin A supplementation protocol, taking 25,000 to 50,000 IU per day for three days. Make sure to take this high-dose vitamin A with at least 10,000 IU vitamin D and at least 90 mcg of vitamin K2.

Vitamin D

Vitamin D plays multiple vital roles in the immune system and works in synergy with vitamin A. (22) To dose up your body with vitamin D, try to get outside every day for a walk, with your arms, face, and (if possible) legs exposed to the sun. You can also take a vitamin D supplement, making sure to balance it with vitamins A and K2, take cod liver oil, eat fatty cold-water fish, or use a vitamin D lamp such as the Sperti UVB Phototherapy Lamp.

Zinc

Zinc lozenges have been extensively studied for their benefits in preventing and reducing the duration of the common cold, which is typically viral in origin. (23) If you feel an illness coming on, you can take 50 mg of zinc for a few days, and then stop the supplement once you feel better. For maintenance, I recommend getting zinc from foods such as grass-fed red meat, poultry, and seafood such as oysters.

Vitamin C

The research on supraphysiological doses of vitamin C and antiviral immunity is conflicting; some studies suggest that high doses of vitamin C reduce cold duration while others indicate no effect. (24, 25) I believe that maintaining a physiological level of vitamin C, which you can achieve by eating plenty of fresh fruits and vegetables, is the best way to support your vitamin C status. Good food sources of vitamin C include broccoli, bell peppers, citrus fruits, strawberries, and kiwi.

Botanicals with Immune-Supporting Properties

Due to my own struggles with Lyme disease and chronic illness, and my work as a technical writer in the nutraceutical industry, I’ve become very well-versed in botanical therapies! Based on my research, I recommend using adaptogenic herbs as an adjunct to nutrition to support your antiviral immune defenses. A few of my favorites include Rhodiola rosea, Astragalus membranaceous, and Eleuthero (Eleutherococcus senticosus). Bioactive compounds in Rhodiola boost immune function, Astragalus has direct antiviral activities while also bolstering the body’s immune defenses, and Eleuthero helps balance the stress response, which can reduce immunity when it is hyperactivated. (26, 27, 28)

I hope you’ve found this article informative and empowering! There is so much you can do with food and nutrition to support your immune system. Stay tuned for Part 2 of this blog series, in which I’ll discuss lifestyle practices for optimizing your immunity against COVID-19, and other viral infections.

Affiliate Disclosure: Should you choose to purchase any of the items I’ve linked to in this article (all of which I have tried and tested myself!), I will receive a small commission. This commission helps to support my website, so I can continue bringing you informative, actionable, free nutrition, and health content. Thank you for your support!

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