21 Immune System Boosting Foods - Kaldzar
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21 Immune System Boosting Foods

Shopping for Healthy, Immune-Boosting Foods. Image by Michael Burrows, cropped.

21 Immune System Boosting Foods

Our bodies are constantly under attack from outside invaders that wish to use us as hosts. Luckily, our bodies’ natural defense systems are designed to recognize and eliminate these intruders. However, if your immunity is weakened, and the pathogen is able to establish a home in or on you, you may experience sickness and disease. We’re all about helping you stay as healthy and active as possible all year round. So today I’m going to provide some information about the connection between your digestive system and immune system, and ways to strengthen both. Then I’ll share a list of some effective and favorite immune system boosting foods.

A Note About Immunity-Booster Foods and COVID

Virus. Image by CDC

Importantly, we must clarify that no food or supplement will directly cure or prevent disease. Rather, eating healthy foods with the correct balance of nutrients helps support your natural defense systems. With regards to the current coronavirus pandemic, you should understand that a dietary change cannot protect you from COVID-19. The best protection from the SARS-CoV-2, the coronavirus that causes COVID-19, is proper hygiene and social distancing. But if you do come in contact with it, a healthy immune system can help your body fight the invading pathogens, possibly lessen severity of symptoms and recover more quickly. Keep reading to find out more about what to eat to strengthen your immunity defense system.

What are Pathogens?

Before we talk about solutions, let’s take a moment to review “the problem”. Simply put, a pathogen is an organism that causes disease within (or on) a host’s body. In order to survive, thrive and reproduce, a pathogen sets itself up in a host’s body. If it avoids the immune responses of the host, it then uses the body’s resources to feed and replicate. Finally, the pathogen exits the host and spreads to a new one.

Transmission method varies by the pathogen type. But common means of spreading are: skin contact, bodily fluids, airborne particles, and contact with feces. Additionally, some pathogens can survive for a time on outside surfaces, so you may even pick one up by touching an object previously touched by an infected person.

Types of Pathogens

The four most common pathogen types are:


A virus is a simple organism made up of a piece of genetic code (DNA or RNA) which is protected by a protein coat. Viruses look to enter the cells of your body, then use the components of the cells to replicate. Once virus replication is complete, the new copies burst from the host cells, typically damaging or destroying the infected cells in the process.

Bacteria and Viruses. Original image by Monstera. Cropped.


A bacterium is a simple, single-celled microorganism. These microbes are extremely diverse, coming in a variety of shapes and capabilities. There are tens of thousands of bacterial species, which have adapted to living in just about every environment. This includes on and in the human body. This may sound shocking, but you actually carry more bacteria cells on your skin and inside your body than the total number of human cells you are composed of! Luckily, as we’ll see, not all germs cause infections. In fact, many bacteria are beneficial for you, and necessary for your health.


A fungus is not an animal, but it’s not a plant, either. You may recognize them as mold, yeast, and mushrooms. While there are millions of fungal species -many of which are beneficial to us- about 300 are known to cause sickness.


A parasite is a tiny organism that feeds from the resources of the host on which (or in which) it is living. Again, there are a wide variety of parasites, ranging in size and complexity, and living environments. The kinds of parasites that commonly cause disease in humans are single-celled protozoa and amoebas, helminths (worms), and ectoparasites like ticks.

As you can see, there is a huge list of different organisms trying to invade and harm your body. Each has a different means of attack and survival; therefore, there are a multitude of symptoms and diseases they can cause. Accordingly, treatment for each will vary. Definitely go see a doctor for appropriate diagnosis and support if you feel you are fighting an infection. But also take care of your healthy daily in order to keep your immune system as strong as possible. Along with good hygiene, this gives your body the best chance to prevent and fight sickness.

Learn more: What is a Virus? And How Do I Fight Them?

Immune System Summary

Viruses and the Human Body. Image by Monstera

Your immune system exists to protect you from foreign and harmful invaders of all types. It consists of organs, proteins and a specialized group of cells that work together to recognize, identify and fight any harmful substances or organisms that have made their way into the body. When your immune defense system is working well, you probably don’t even notice – you are healthy. However, if your system is run down or otherwise not working correctly, your immunity is lowered and you may be more likely to get invaded, infected and made ill.

At a high level, your immune system is comprised of two subsystems:

The innate immune system acts like a general defense. Its immune cells – killer cells and phagocytes- are non-specific and defend you from a wide variety of pathogens.

The adaptive immune system differs in that it targets specific pathogens that your body has already encountered previously. That is why it is also referred to as the acquired or specific immune response. As its name suggests, this system adapts to changes in the bacteria and viruses it fights. Thus, it remembers past infections and learns to defend the body going forward. 

Your Digestive System Supports Your Immunity

As touched upon earlier, you are host to lots of microorganisms. In fact, trillions of them! Most of these are bacteria, and the vast majority of these live in your digestive system. But these are not infectious, harmful bacteria. They are extremely beneficial to you in a number of ways, especially to your immunity. Modern research shows that 70-80% of your immune system actually resides in your gut, and much of this is dependent upon the resident bacteria.

Gut microbiota. This file is licensed under the Creative Commons Attribution 4.0 International license. Author: DataBase Center for Life Science (DBCLS). https://doi.org/10.7875/togopic.2020.154

Your digestive and immune systems support each other to promote a healthy body. For example, certain cells in the lining of the digestive tract excrete massive quantities of antibodies into the gut. Researchers are still studying the types of antibodies being made, and how the body uses these to control the interaction between ourselves and bacteria.

Typically, antibodies will attach to harmful cells like viruses and bacteria, flagging them for removal from your system. But in order for this to be effective, the antibodies must ‘know’ which foreign substances and cells are “bad” and should be removed, and which bacteria are “good” and should be left alone.

Therefore, your gut microbiome acts as a gatekeeper and teacher/trainer. It teaches immunity cells called T-cells to tell the difference between our own cells and foreign, harmful substances and organisms. When the antibodies fail and our cells get infected, T-cells jump in to destroy the infected cells and prevent further spread of infection. This process is referred to as cell-mediated immunity.

Grow Your Healthy Gut Garden

Gut Garden Full Stack

Eating all the good, healthy, whole foods in the world won’t give you all their benefits if your digestive system is not working properly. So before we get into the foods that help boost your immunity, we need to take a moment to address your gut microbiome itself. Make sure that you are eliminating toxins and waste efficiently, and promoting all the good bacteria that support your health. You can get all of this, and more, with products such as the GoodGut Program from Gut Garden. This 5-stage regimen is designed specifically to heal your gut while restoring and bringing balance to your digestive system. Each stage can be purchased separately if you have just one need, but the system works best when completed in full.

  • Activated Charcoal to safely absorb and remove toxins from the digestive tract.
  • Digestive Enzymes with Betaine HCL and Pepsin to replace digestive functions that may be depleted or compromised.
  • Perfect Probiotic to repopulate healthy bacteria for improved metabolism, digestion and immune function. 
  • Resistant Starch Prebiotic to enhance beneficial bacteria & promote microbial diversity. 
  • Collagen Peptides to help restore and strengthen the intestinal lining.

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Immunity-booster foods

In order to boost you immune system with food, eat a wide range of fruits, vegetables and other natural whole foods. This will ensure you are getting a balanced diet full of the macro- and micronutrients needed to build and support your immune cells. Additionally, you’ll feed and replenish those helpful bacteria that play a role in keeping you well. Here are 21 immune system boosting foods that you can incorporate into your eating habits today.

Improving your diet by cutting out processed foods and including more prebiotic fiber can increase biodiversity. Also, having probiotic-rich foods such as kefir, sauerkraut, and probiotics may restore the composition and reintroduce strong microbes, allowing for a more efficient gut microbiome, immunity and cognitive abilities.

1. Citrus Fruits

Citrus Mix

Most citrus fruits are high in Vitamin C, which helps increase the production of white blood cells. Also known as leukocytes (or leucocytes), these cells are key to fighting infectious disease and other foreign invaders. Importantly, your body does not store Vitamin C; therefore, you need to replenish your stores with 75-90mg per day. Popular citrus fruits are: oranges, grapefruit, lemon, lime, tangerines.

2. Red Bell Peppers

While we’re talking about Vitamin C, did you know red bell peppers have nearly three times the amount as oranges? It’s true! Additionally, they deliver a healthy dose of beta carotene. Your body converts this to Vitamin A and uses it (among other things) to keep your skin healthy. And of course, your skin is your first barrier against the outside world and all the germs out there.

3. Broccoli

Boy Loves Broccoli

Broccoli is one of the best vegetables for you to eat because it is packed fiber, Vitamins A, C, and E, and other antioxidants. The fiber helps keep your gut moving and healthy. Vitamin E is particularly useful in fighting heart disease, cancer, eye disorders, and cognitive decline. But its antioxidative and anti-inflammatory effects also contribute to immune enhancement.

4. Spinach

Like other vegetables listed here, spinach is packed full of beta carotene, Vitamin C, and a number of other antioxidants. It is also a good source of Vitamin E. This fat-soluble vitamin is powerful antioxidant that helps the body fight off infection. Load up on these leaves to increase the infection-fighting ability of your immune system. Try our super-powered spinach pesto recipe on pasta, poultry, fish, sandwiches and more!

Try this Super Salad Full of Antioxidants, Polyphenols and Other Micronutrients

5. Garlic

That kick that garlic gives food is a sign of its immune-boosting power. The distinct aroma and flavor is due sulfur-containing active ingredients such as alliin, which your body converts to allicin. This compound is shown to boost the disease-fighting response of white blood cells. Which means they are better able to attack when they detect viruses such as the common cold or flu. However, note that research shows garlic can help prevent sickness, but does not shorten one’s recovery time.

6. Ginger

Ginger Root with Flowers

Ginger is another pungent superfood. The main bioactive compound in ginger is gingerol. Besides reducing nausea and helping with digestion, this oil has powerful anti-inflammatory and antioxidant effects. Moreover, it is shown to inhibit the growth of many types of bacteria, which means it can help you fight bacterial infections. Use it fresh, dried, powdered, or as an oil to add a spicy and beneficial kick to a wide variety of dishes. Or even try a shot of pure ginger juice!

7. Almonds

Because Vitamin E is fat-soluble, it requires the presence of fats to be absorbed by the body. Almonds (and other nuts) are packed with Vitamin E and also have healthy fats. Therefore, they make an efficient way get your dose of this immune-boosting antioxidant. Use almond butter in these chocolate buttercups for a sweet yet healthy treat!

8. Sunflower Seeds

Although tiny, sunflower seeds carry huge immunity-boosting benefits because they are full of nutrients such as phosphorous, magnesium, and Vitamins B-6 and E. As stated, Vitamin E plays a big role in regulating and maintaining immune system function. But another star nutrient of sunflower seeds is selenium. A number of studies have been conducted to show its effectiveness at fighting viral infections.

Read More About Micronutrients and How to Get Them

9. Yogurt


There is a huge variety of yogurt out there, and some are not as good for you as others. Look for those that include live and active cultures, and are not flavored with extra sugar or artificial flavorings. A good example is Greek yogurt. The Vitamin D helps regulate the immune system. And the live cultures act as a probiotic that help promote a healthy gut, which further stimulates your immune system to help fight diseases.

10. Turmeric

A relative of ginger, turmeric makes this list due to its high levels of curcumin. This compound decreases exercise-induced muscle damage. But studies also indicate that it provides a boost to your immune and has antiviral properties. Looking for a way to get more turmeric into your day? Try this bulletproof coffee recipe.

11. Green Tea

Many teas provide you with flavonoids, a type of antioxidant. However, green tea is especially good for you due to its high levels of epigallocatechin gallate (EGCG). This powerful antioxidant has been shown to boost immunity. Additionally, brewed green tea is a good source of the amino acid L-theanine, which may aid in the production of germ-fighting compounds in your T cells.

12. Papaya


Papayas are good for you in multiple ways. First off, they contain fair amounts of potassium, magnesium, and folate. All of these are good for your overall health. Secondly, they are loaded with Vitamin C; in fact, one fruit can contain twice your RDA of this vitamin. Next, the fiber in papaya helps keep your gut regular. Additionally, papayas deliver a strong dose of papain, a digestive enzyme that carries anti-inflammatory benefits.

13. Kiwi

Kiwis are another great source of Vitamin C. In addition, they are naturally full of a ton of essential nutrients, including folate, potassium, and Vitamin K. So the Vitamin C helps boost your white blood cells and your immune defense systems. And the other nutrients help keep the rest of your body running properly.

Use These Tools to Make Sure You’re Eating a Balanced Diet

14. Sweet Potato

These tasty tuberous roots are loaded with beta-carotene and Vitamin A, which are essential in fighting off infections. They also provide antioxidants which help protect your body from free-radical damage, inflammation and chronic disease.  Additionally, their high level of fiber promotes the growth of good gut bacteria and contribute to a healthy gut. Click here to learn more about sweet potatoes and an easy recipe so that you can include more into your immunity bosting diet.

15. Chicken Soup

Chicken Soup is good for your Immunity

In general, poultry is good for your immune system because it is high in Vitamin B (aka pyridoxine). This water-soluble vitamin is used in many metabolic functions, as well as in the production of red blood cells and neurotransmitters. But the immune-boosting properties increase when you boil the bones to make broth, stock and soup. This releases the gelatin and chondroitin, which help gut healing and immunity. Moreover, the carnosine found in the soup can actually help protect you against viruses like flu.  

16. Shellfish

This is a tricky one. Shellfish like oysters, mussels, lobster and crab can help boost your immune system because they contain zinc. Getting the right amount of this mineral helps your immune cells function properly. Plus, it is used in the creation and activation of white blood cells. However, consuming too much zinc per day may inhibit some immune response. So try to stay close to the recommended daily intake of about 11mg for men, 8mg for women.

17. Mushrooms

I recently wrote about how mushrooms are so good for weight control. And certainly, a healthy body weight lessens the stress on your (immune) systems and promotes overall health. However, mushrooms also give you the mineral selenium, and the B vitamins riboflavin and niacin. These vitamins help support a healthy immune system. And as mentioned, selenium may help you fight off flu, or at least reduce the severity of infection.

18. Miso

Miso Soup

Traditional miso is made of fermented soybeans. Much like yogurt, this salty paste is good for you due to its high levels of probiotics. These “good” bacteria are beneficial to your digestive health. And as we’ve mentioned, as healthy gut supports a healthier immune system and a healthier you.

19. Watermelon

We love watermelon because it is such a refreshing, sweet treat. But it also delivers a hefty dose of glutathione. Like others on this list, this antioxidant strengthens the immune system so it can fight infection. Tip: the concentrations of glutathione are highest in the red pulp near the rind.

20. Acai Berry

Acai Berry Bowls

These dark purple-blue berries get their color from the anthocyanins they contain. These antioxidants help battle free radicals and promote an overall healthier. Try them as a juice, blended in a smoothie, or mixed into yogurt. And this acai bowl recipe will surely have you eager to pack in more anthocyanin!

21. Elderberry

Much like acai, elderberries get their color due to being loaded with antioxidants. It’s almost impossible to have too many of these inflammation- and free radical-fighting compounds. Studies have shown concentrated formulas of elderberry antioxidants can even block the flu virus. So use these berries -fresh or in supplement form- to boost your immunity.

Bringing it Home

Your immune system and digestive system are both complex, as is the interaction between them. However, their relationship is well established. So hopefully you can use the information above to stay healthier and free of pathogen-caused illness.

The important concepts to remember are:
– Support your immune system to support your overall health and avoid infection.
– Support your gut health to support your immune system.
– Respect the beneficial bacteria in your gut. Feed it and help it thrive. And replace it after bouts of antibiotics or chemotherapy.
– Nourish your gut microbiome with immune system boosting foods, including probiotic bacteria and the prebiotics they feed upon.
– Keep a check on the harmful bacteria. If you are not feeling well, get checked to see if you need to take action to reduce a harmful overgrowth.

We love Gut Garden because they understand just how important our digestive health is to our daily comfort and overall well-being. We use their products to Clean, Prepare, Plant, Feed, and Protect our gut; and encourage you to try it, too.

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You can save 10% off any product when you start a subscription.
Save an additional 10% off all orders when you use our discount code: KALDZAR!

Dave Hughes

Editor and Contributing Author at Kaldzar

Certified Biologist and Data Scientist
Constantly curious; Curiously compassionate

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