Fortifying Immunity with Food - Lakeside Natural Medicine

Natural Health and Wellness for the Whole Family

Fortifying Immunity with Food

BySarah Axtell, ND March 27, 2020

I am a firm believer in “food is medicine.” Now is the time to prioritize a healthy diet to give your body the nourishment it needs to stay healthy. The goal of this blog post is to provide you with sound information to support your immune system and maintain resiliency in a time of a pandemic.

We’ll get to the nutrition foundations to improve your immune competency, but first a little background on COVID-19 and the inflammation link. This virus can cause serious lung damage due to the inflammatory process (ie. cytokine storm) that occurs with the infection. This inflammatory process can cause hardening of the lung tissue and the alveoli. The people that are at higher risk for severe COVID-19 illness are those with chronic inflammatory conditions, such as diabetes, heart disease, obesity, cancer and pre-existing lung disease.

So the goal is to not only fortify our immune system with immune-supportive nutrients, such as vitamin C and Vitamin D, but it is also important to reduce inflammation. Try to minimize the top inflammatory foods, such as sugar, gluten, dairy, and alcohol, at this time.

Core Nutritional Foundations to Improve Immune Competence:

  1. Eat the Colors of the Rainbow This means including plants, plants, and more plants in your diet. Eat a rainbow to get a variety of phytonutrients, antioxidants, and micronutrients. The goal is to fill 75% of your plate with plants. It may be difficult to get to the store to get fresh fruits and veggies so frozen is just fine. When you can get to the store (or even better get your items delivered!), emphasize longer-shelf produce items.

Here is a list of some of my top quarantine must-haves:

  • Citrus (I am loving Cara Cara oranges right now- so good and an excellent source of vitamin C)
  • Peppers- excellent source of vitamin C
  • Root vegetables (beets, sweet potatoes, carrots)
  • Winter squash
  • Onions and garlic
  • Ginger
  • Mushrooms- see below on the health benefits of mushrooms
  • Frozen spinach (add to your smoothies, tomato sauce
  • Whole grains (quinoa, teff, buckwheat, oats, brown or wild rice)
  • Nuts and seeds
  • Peanut butter and almond butter
  • Almond milk
  • Almond flour
  • Eggs
  • Frozen berries (blueberries, strawberries and acai berries, a vitamin C powerhouse)
  • Frozen vegetables
  • Canned tomatoes
  • Canned coconut milk
  • Canned beans
  • Canned safe-catch tuna and salmon
  • Canned pumpkin for Gluten-Free Pumpkin Muffins
  • Broths for soups

  1. Vitamin C: Vitamin C is our immune supportive all-star nutrient. In fact, IV vitamin C is improving outcomes in cases of seriously sick coronovirus patients. Our vitamin C status can be compromised by smoking, air pollution, and a processed diet.
    • Food sources- Citrus fruits, acai berries, broccoli, bell peppers, kiwi
    • Supplement- 1000 mg 1-2x/day
  1. Vitamin D: If the sun is shining, take advantage and go outside to soak up some vitamin D. A 2019 meta-analysis revealed vitamin D supplementation was safe, and it protected against acute respiratory infections. Ideally, we want vitamin D levels between 60-80 for an optimal immune system.
    • Food sources- There is a small amount found in fatty fish, such as salmon and tuna.
    • Supplement- 1000-5,000 IUs/day depending on your level. Consult with your doctor regarding the best dose for you.
  1. Quercetin: Quercetin is a flavonoid found in many fruits and vegetables. I typically recommend it to patients during the Spring for seasonal allergies. It makes sense to include it in your diet given our current pandemic.  It has anti-histamine, anti-inflammatory, and anti viral properties. In fact, flavonoids, including quercetin, have been reported to target Coronaviruses (CoV), specifically SARS-CoV.
    • Food sources- Red onion*, apples, berries, cruciferous vegetables (broccoli, cauliflower, brussel sprouts), grapes, capers, and elderberry.
    • *Food is medicine tip– The skins and the outermost rings of red onions contain the highest concentration of quercetin. When you make a stir-fry include the skins of red onion and then discard at the end. This will fortify your meal with quercetin from the skins (without having to eat them!).
    • Supplement-  500 mg 3x/day. Combine with vitamin C for optimal absorption.
  1. Zinc: Zinc mediates adaptive immunity. We don’t store zinc in the body, so we need adequate zinc intake from our diet on a daily basis. It is one of the most common nutrient deficiencies I see. Zinc deficiency leads to lower lymphocyte activity, which is a problem with it comes to fighting viruses. Take a look at your nails- a sign of  zinc deficiency is white spots on your nails.
    • Food sources- Nuts and seeds, especially pumpkin seeds* and pine nuts. Oysters, seafood, and grass-fed meat are also good sources.
    • *Food is medicine tip- I like to grind raw pumpkin seeds into a powder (using my blender, food processor, or coffee grinder). I then add ground pumpkin seeds to smoothies, homemade granola, pumpkin muffins, and pancakes. My kids don’t detect them this way!
    • Supplement- Zinc picolinate 30 mg/day. Take with food.
  1. Selenium– Selenium is our anti-viral trace mineral. It can speed up virus resolution. And bonus- it is supportive for your thyroid.
  1. Include warming, anti-inflammatory spices. This includes turmeric, ginger, garlic, and onions.
    • *Food is medicine tip- When cooking with turmeric, combine with a fat (avocado oil or coconut oil) and black pepper for optimal absorption. Also, when cooking with garlic, add it at the end (as opposed to sauteing it in the beginning of your meal) because its anti-microbial effects are most potent when raw.
  1. Eat Fermented Foods Daily- Approximately 70% of your immune system is located in your gut. Include fermented foods in your diet to diversify the microbes in your gut, thus strengthening your immune system. Eat sauerkraut, kimchi, plain yogurt, and kefir.
  1. Make Mushrooms a Staple- Mushrooms contain glycans (fiber) that raises our immune cell activity. Shitake mushroom in particular improves immunity by way of improving cell proliferation and activation and boosting SIgA. Shitake has also been found to have anti-inflammatory effects.
    • Food sources- Any and all mushrooms are good for you. Varieties that are especially immune supportive include shitake, reishi, and maitake.
    • *Food is Medicine Tip– Include mushrooms in any and all soups. Here is my Immune Strengthening Soup.
    • Supplement- Mushrooms in supplement form can be taken in dried form (capsules) or liquid form. Host Defense is a reputable company, providing organic and sustainably cultivated mushrooms.
  1. Drink Tea. Drink tea everyday, specifically black tea, thanks to its ability to inhibit SARS-CoV replication. Green tea also has been shown to have anti-viral activity. And bonus- green tea contains L-theanine, which has an anti-anxiety effect. We could all use some L-theanine in our lives right now! Aim for 2-3 cups of tea per day.

I know the tendency is to gravitate toward comfort foods right now. Rather than choose pizza and pasta, choose nourishing soups and stews. Quinoa and legumes can be hearty and filling. I understand so many of you are scrambling right now, juggling a whole new “normal” during isolation. If you love to cook, now is the time! If you don’t love to cook and/or just can’t prioritize it right now, that’s ok. Opt for pre-made soups and chili at the store, stock up on frozen vegetables, and experiment with making smoothies with frozen berries and frozen greens. Load up on pre-made cauflilower crusts and top with your favorite pizza toppings. Or simply just add some mushrooms to a broth or soup for a quick “food is medicine” punch.

If you are craving something sweet or love to bake, check out some of my favorite healthy sweet treats:

Double Chocolate Mint Cookies

Peanut Butter Chocolate Chip Energy Bites

Grain Free Chocolate Chip Cookies

Above all, be kind to yourself and others during this stressful time.


Please continue to wash your hands frequently and practice social distancing. Please stay home! There are some great grocery delivery services. My favorite are Whole Foods Delivery (through Amazon Prime) for produce and grocery items and Thrive Market for pantry essentials.

Also, note that the information in this article is not meant to prevent, treat, or cure COVID-19, as there is no known research specific to this virus at this time. The information in this article is merely meant to improve your overall immune system and general well-being.

Please continue to be safe. Stay well. Stay home.

Editor’s Note: The information in this article is intended for your educational use only. Always seek the advice of your physician or other qualified health practitioners with any questions you may have regarding a medical condition and before undertaking any diet, supplement, fitness, or other health program.

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