By Thais Harris, BCHN


The subject of immunity has never been so central to our everyday lives as it is now, and for good reason: healthy immunity is vital for not just surviving but thriving during a pandemic. Add back-to-school concerns and changing seasons to the mix, and our immune system deserves our full attention. Thankfully, there are many ways we can support our immunity, namely through diet and lifestyle practices.

The immune system is a complex network of cells, tissues, and organs that help the body fight infections and other diseases (NIH, n.d.). As such, it is not a single entity, making it difficult to isolate specific nutrients or practices that are proven to boost it. It isn’t about one magic herb or food or type of exercise. It is about our dietary patterns and practices that lower stress and inflammation, which in turn allow for a stronger and more precise immunity.

In this article I want to focus on such foods and practices without getting into the details of what comprises the immune system and how exactly it works. For more details on the immune system, stay tuned for my next post, and check out this short video to get a better understanding.

Here are the top 5 foods to boost immunity. Keep reading for lifestyle practices and what to avoid, as well as how to put this into practice for you and your family (with recipes your kids can make too!).

1 – Eat the rainbow, and mostly more vegetables!
Fruits are good too, but the key is increasing vegetables.

Turns out only 9% of Americans – less than 1 in 10 – eat the recommended amount of vegetables, and only 12% meet the recommendations for fruit (CDC, 2017). There are thousands of studies proving the benefits of higher vegetable consumption and showing how the lack of it contributes to disease.

So what does an ideal amount of vegetables look like in a day, and what kinds are especially good for immunity?

According to the CDC, the amount of vegetables you need to eat depends on your age, sex, and level of physical activity. The amount each person needs can vary between 1 (for toddlers) and 3 (adults) servings each day. In functional medicine, the ideal amount is 5 servings a day for adults and 2-4 for kids, which is the recommended amount not just for avoiding disease, but thriving!

In general, 1 cup of raw, 1/2 cup cooked vegetables or vegetable juice, or 2 cups of raw leafy greens can be considered as 1 serving of vegetables. Add another 2-4 servings of fruit to get enough color into your diet, focusing on low-glycemic fruits such as berries, cherries, apples and stone fruit, with the skin on.

I love this table from the PaleoMom:

Vegetable Servings Illustrated

Color matters: the phytonutrients that give vegetables and fruits their natural color have antioxidant and anti-inflammatory qualities that are highly beneficial to our health. Vitamins C, E, A, and the minerals zinc and selenium contribute directly to a healthy immune response, and can be found in green, orange, red and purple vegetables and fruit.

Vitamin A (from its precursor beta-carotene) is especially helpful in supporting the thymus gland (Murray & Pizzorno, 2012), which is the training center for immune cells, where they learn how to fight invaders. The thymus shrinks with age, becoming fatty tissue by the time we reach our 80’s – which is one of the reasons we tend to have a lower immune response at that point. Getting enough nutrients to halt thymus gland shrinkage is key. Beta-carotene-rich veggies and fruit: carrots, yams, kale, spinach, chard, mango, pumpkin.

Vitamin E is the most important antioxidant present in body tissues of all cells and is crucial for normal function of the immune cells (Pekmezci, 2011). Vitamin E-rich veggies and fruit: avocado, spinach, chard. Other plant foods rich in vitamin E include almonds and sunflower seeds.

Vitamin C contributes to immune defense by supporting various cellular functions, including helping our skin protect us against pathogens (Carr and Maggini, 2017). Among its many other roles, vitamin C is the nutrient that allows cells to fully differentiate, meaning they use vitamin C as the fuel that allows them to develop their specific function in the body, especially in the case of T and B cells, which are our immune soldiers. Vitamin C-rich foods: spinach, bell peppers, citrus, berries, papaya.


Bone broth

2 – Bone broth

Grandma’s chicken soup could cure everything for a reason. Many reasons, actually. It is easy to digest and packed with protein and minerals. It is hydrating and contains the amino acids glycine and proline, which have anti-inflammatory properties. It helps thin nasal secretion. It provides collagen/gelatin, which is soothing and healing to the gut lining and improves digestion. And what does the gut have to do with immunity? 80% of our immune system is located in the gut! Repairing and enhancing gut health translates to stronger immunity.

These and other amino acids produced in chicken bone broth also reduce inflammation in the respiratory system (Rennard, et al, 2000), which is especially important right now. My 5 year old loves bone broth and sips it like a cup of tea, with a little lemon squeeze to make the flavors pop. Making your own broth is easy and you can add a variety herbs and spices to make it even more potent as a healing food. I keep veggie scraps in a bag in the freezer and add to my bone broth for extra flavor and minerals… it feels good to honor the whole animal and the whole plant by using every bit of them. General rule of thumb is 2 lbs of bones to 3 quarts of water, plus your veggies. Cook for at least 4 hours – I like making mine with the slow cook option in my Instant Pot over 24 hours.

If you do not consume animal products, a powerful veggie broth can also offer immune help, such as this broth from Ceres Community Project.


3 – Probiotics

Our microbiome outnumber our human cells 10 to 1. These trillions of organisms protect us from pathogens, regulate – and are an intricate part of – our immune system, and are in constant conversation with our cells and our brain, having an important role in mental health and mood regulation. It is imperative to feed these organisms with the appropriate prebiotics – foods such as onions, garlic, leeks, bananas, asparagus and sweet potatoes, as well as to replenish live organisms by consuming probiotic foods such as sauerkraut, kimchi, tempeh, miso, raw apple cider vinegar, kefir, and yogurt (commercial yogurts aren’t always a good choice, especially if they have added sugars, and should ideally be homemade to ensure live organisms). In some cases supplementation might be warranted, especially when under stress and after the use of antibiotics. I like’s probiotics, as well as Innate Response’s Flora 20-14.


4 – Fiber!
Foods like flax seeds, oranges, apples, carrots, Brussels sprouts, oats, brown rice, and legumes slow the absorption of sugar and help improve blood sugar. Since sugar diminishes our immune response (studies show 8 teaspoons of sugar, equivalent to a glass of soda, puts our immune cells to sleep for hours) and induces the aberrant activation of the innate immune system, including inflammation (Zhang & Jin, 2018), it is clear that reducing sugar consumption and increasing foods that help us regulate blood sugar are critical for proper functioning of our immune system. Soluble fermentable fiber feeds our beneficial gut flora (a prebiotic nutrient), which in turn release butyrate, helping to regulate the immune system, and helping our bodies heal more quickly from infections. Fiber also plays a big role in detoxification, binding to toxins, hormones and used cholesterol to escort them out of our body, keeping the flow of nutrients in and toxins out, so we are not already overwhelmed when an infection occurs.


5 – Organic is not a gimmick. What we eat becomes us.

Pesticides, insecticides, and herbicides are found in conventionally grown (non-organic) produce, whole grains, nuts, seeds, and legumes, as well as animal products. In the US alone, 1.1 billion pounds of pesticides are sprayed on or added to food crops each year (EPA, 2017), adding to almost 3.5 lbs of toxic chemicals for each man, woman and child. A heavy toxic burden interferes with our microbiome, detoxification, digestion, mental health, cardiovascular health, and the list goes on. Eating clean, organic food helps to reduce our exposure to toxins, and can increases our exposure to antioxidants, which is especially significant for the immune system. When foods are organically grown, they are also contributing to the health of the farmers, the soil, the water, the air and the community.



1 – Mindful breathing
Take some time to connect with your body and take deep belly breaths. You can give the breath a quality such as a color or light to help you visualize it traveling in your body. You can also add an affirmation as you breath in and out to focus your attention. Anything from Let (as you inhale) and Go (as you exhale), or I am (as you inhale) Healthy (as you exhale) can help – say what rings true or is needed for you. Belly breathing activates the vagus nerve, helping the whole body come into a parasympathetic mode, which is the rest and digest state that allows for immunity to work properly (rather than fight or flight mode). There are various apps for adults and kids, and I especially like Insight Timer and Calm. For kids there is a lovely story on Amazon called Dreaming of Ponies that can be used as a meditation/breathing exercise for little on Mindful Kids: 50 Mindfulness Activities for Kindness , Focus and Calm is another helpful tool.

2 – Sleep!
Much of the cell maintenance, repair and rejuvenation we need on a daily basis happens while we sleep. When we short ourselves on sleep, we reduce our capacity to maintain and repair all functions in the body. Kids and adults have different requirements. 3 to 5 year olds need 10 to 13 hours, 6 to 13-year olds need 9 to 11 hours, 14 to 17-year olds need 8 to 10 hours and adults need at least 7 hours (and up to 9 hours) of zzz’s.

3 – Movement
Moderate exercise, swimming, walking, riding a bike hiking in nature (bonus points for anything in nature), dancing can all be incorporated into our daily lives to move lymph (another important part of our immune system) and helps us detoxify by sweating out toxins. Check out yoga for kids at Cosmic Kids.



Although most of the time we want to get our nutrients from food because they are often perfectly combined with synergistic compounds that help us absorb them, there are times when supplementation can make a bigger impact, especially when kids are going back to school or before traveling and other situations when we might be more exposed and more vulnerable to communicable diseases.


Vitamin C – we can get lots of vitamin C through food, but when cold and flu season comes (or in the middle of a pandemic), a higher dose of vitamin C can be very efficient to keep immunity in tip-top shape. Vitamin C may reduce the duration of illness as well. I like the brands Innate Response, Metagenics and Designs for Health. Ideal dosage for 1-3 year olds is 250 – 750 mg and 3+ years old 1,000 mg, which can be given in divided doses throughout the day to check for bowel tolerance (too much can cause diarrhea).

Vitamin D – from COVID-19 outcomes to depression, vitamin D is a well-studied, essential part of good health. Unfortunately a huge part of the population is deficient in it. We synthesize this vitamin through sun exposure, but as we spend more time indoors, and in winter months when we don’t get enough UV rays to begin with, supplementation is recommended. Dosage will depend on Vitamin D status, and a good maintenance dose is 2,000 IUs during winter months. The vitamin D council recommends 1,000 IUs (International Units) per 25 lbs. I like the brands Thorne and Designs for Health. Food sources of vitamin D include salmon, sardines, (pasture-raised and organic) butter and eggs.

Black Elderberry (Syrup) – In controlled studies and meta-analysis (when researches look at a group of studies), supplementation with black elderberry was found to substantially reduce upper respiratory symptoms, and cold duration (Porter, 2017).  Its antiviral and antimicrobial properties have been demonstrated in various populations and conditions, and it is currently indicated to strengthen immunity to possibly prevent Covid-19 (Masterjohn, 2020). According to Chris Masterjohn, “human studies using elderberry to combat the common cold and flu have all used 700-900 milligrams of elderberry extract per day, divided in two to four doses, either as lozenges, capsules, or syrup. When a syrup was used, it was four tablespoons per day of Sambucol, which provides a little over 750 milligrams of extract. Some elderberry syrups have as much as 1200 mg of extract per tablespoon, however, so always consult the label of the product before deciding on a dose.” I like Designs for Health Immunoberry blend.



After increasing our consumption of vegetables, probiotics, fiber, and adding bone broth to our week, and procuring organic foods, there are a few things we will want to remove or avoid in our day-to-day. The main immune-suppressing foods are:

  • Sugar and refined carbohydrates (reduce activity of white cells, create inflammation)
  • Damaged omega-6 fats in refined vegetable oils and processed products containing them. Contribute to inflammation and poor detoxification.
  • Hydrogenated fats – contribute to inflammation, cell membrane rigidity, arterial damage. Look in the ingredients list for anything hydrogenated or partially hydrogenated, even if the label says 0 g trans fats!
  • Foods we are sensitive or allergic to: these can over-activate the immunity system, causing inflammation and potentially creating auto-immunity.



– Start by offering a range of colorful vegetables with every meal, and encourage consumption of a variety foods, not the same stuff every day or every week.

– Have a small amount of fermented foods with lunch and dinner (a spoonful of sauerkraut, some kombucha mixed with water for a special beverage), use herbs and spices liberally, and serve teas such as ginger and lemon during meals to enhance digestion.

– You can have your kids explore a new fruit or vegetable each week (Where does it grow? What colors does it have? Is it sweet or sour? How is the texture?) – and draw on a white board or paper a rainbow where the kids get to fill in how many colors they eat each day.

– Add ½ cup shredded carrots to salsa, or beets to make a pink hummus.

– Make pesto using kale, spinach, cilantro, and/or basil and then add sunflower seeds for vitamin E (and skip the expensive pine nuts). You can then add the pesto to omelets, sandwiches, pasta, roasted vegetables and fish or chicken.

– Serve veggie stuffed omelets, make green smoothies and make veggie wraps such as the one below. I have taught hundreds of kids to make these wraps, and they love them!



Paper, Veggies, Sauce!

(Rice paper rolls with sweet “no peanut” sauce)

Adapted from Hollie Greene’s JoyFoodly


Rice Paper Rolls

Makes 8 – 10 rolls

  • Rice paper
  • 1 carrot, shredded or julliened
  • 1 cup purple cabbage, shredded or julliened
  • ½ jicama or 1 apple, shredded or julliened
  • ½ red bell pepper, julliened
  • ½ bunch cilantro

Cut or shred vegetables. See what a beautiful rainbow they make. Put 1 cup of water in a bowl, and dip each sheet of rice paper in bowl for 5 seconds. Put wet rice paper on a plate, add about ½ cup of combined vegetables, and roll carefully.

Sweet “Not-Peanut” Sauce

This is a lovely take on Asian peanut sauce, without the peanuts. Instead we use healthy organic sunflower seeds, which are easy (and cheap) to find.

  • 1/2 cup sunflower seeds
  • 1 tablespoon raw apple cider vinegar
  • 2 tablespoons extra-virgin olive oil
  • 2 tablespoons fresh lemon juice
  • 1 tablespoon honey
  • 1 garlic clove
  • 1-inch knob of fresh ginger, peeled and chopped
  • 1/2 teaspoon salt
  • 2 teaspoons tamari, soy sauce, or coconut aminos (optional)
  • 1/4 cup water


Combine all of the ingredients in a high-speed blender, and blend until completely smooth. Add water if a thinner consistency is desired.


Let me know how this goes for you. I am here to support you and your family!

Disclaimer: this article is educational and not intended to substitute medical advice. We do not claim to treat or diagnose any conditions and the practices offered here do not guarantee protection against Covid-19 or any other infectious disease.



Carr AC, Maggini S. Vitamin C and Immune FunctionNutrients. 2017;9(11):1211. Published 2017 Nov 3. doi:10.3390/nu9111211

CDC. Only 1 in 10 Adults Get Enough Fruits or Vegetables. 2017. Accessed 08/23/2020 at

Masterjohn, Chris. The Food and Supplement Guide For the Coronavirus. March 2020.

Murray & Pizzorno. Encyclopedia of Healing Foods. Atria Books, New York, 2005.

NIH. Immune System and Disorders. MedlinePlus. Accessed 08/22/2020 at,This%20is%20called%20an%20infection.

Pekmezci, D. Chapter eight – Vitamin E and Immunity. Universoty of Ondokuz Mayıs, Kurupelit, Turkey. March 2011.

Porter RS, Bode RF. A Review of the Antiviral Properties of Black Elder (Sambucus nigra L.) ProductsPhytother Res. 2017;31(4):533-554. doi:10.1002/ptr.5782

Rennard, Barbara O., et al. Chicken Soup Inhibits Neutrophil Chemotaxis in Vitro. Chest, 2000, Oct: 118 (4).

Yu S, Zhang G, Jin LH. A high-sugar diet affects cellular and humoral immune responses in Drosophila. Exp Cell Res. 2018 Jul 15;368(2):215-224. doi: 10.1016/j.yexcr.2018.04.032. Epub 2018 May 1.