9 Immune Boosting Foods to Ward off the Cold and Flu

Dr. Kimberley O'BrienBlog, Health Leave a Comment

As the cold and flu season approaches, my patients have started asking more and more about proactive, day-to-day ways they can boost their immune system. Of course, this has been even more of a concern for people this year with COVID-19.  The great news is that there are many ways we can support your immune system, and one of the most essential ways to do this is by choosing to fill your plate with immune boosting foods!  This article teaches you to do exactly that, while also minimizing those foods that are dragging down your health and energy.

Although supplements can also be helpful to boost your immune system, it’s absolutely imperative that we first start with getting your diet in check. If you’re not getting the vitamins and minerals your immune system needs to function effectively, supplements are limited in how much they can help!  This is especially true if there are foods in your diet that are putting stress on your immune system, and I’ll also be sharing which foods to avoid or minimize later on in this post. When we optimize your diet FIRST, we can then gain much greater benefits when later adding in supplements for an added boost!

Immune Boosting Foods

9 Immune Boosting Foods to Ward off the Cold and Flu

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1. Garlic

Garlic is hands-down my favourite immune-boosting food!  It contains a natural chemical called “alliin”, that converts to a powerful immune boosting chemical called “allicin” when it’s exposed to oxygen.  Crushing or mincing garlic provides this exposure to oxygen, and adding crushed raw garlic to homemade salad dressings or guacamole is a fabulous way to take advantage of it’s full immune-boosting potential!

Garlic strengthens the way our immune system reacts to and wards off viruses, like the coronavirus. Studies have demonstrated that individuals taking a garlic supplement were less likely to develop a cold, and that those who did were sick for a shorter duration. 

Thankfully there’s no need to supplement garlic in a capsule, and a few cloves can easily be incorporated into your daily diet as a delicious immune boosting food!


2. Ginger

Ginger is what’s referred to as a diaphoretic and lymphatic in herbal medicine, which means it supports the immune system while promoting sweating to help break a fever.  It’s also a well-known remedy for nausea and works wonders to calm an upset stomach!

Ginger has been demonstrated to have antibacterial and antiviral properties, which can help your body to ward off a cold or flu.  I often recommend it to be enjoyed in a delicious immune boosting tea, in salad dressings, and as a seasoning in curries, soups, or stir-fries.

Immune Boosting Foods: Ginger

3. Mushrooms

Mushrooms are exceptional immune boosting foods, with the most potent yet commonly available grocery store varieties including shiitake and oyster mushrooms.  These mushrooms contain immune-modulating polysaccharides that balance and upregulate your immune function, helping to keep you healthy all year long!

How do you incorporate these mushrooms into your daily diet?  Simply throw them in as a delicious addition to any curry, soup or stir-fry!  With a slightly meaty texture, both oyster and shitake mushrooms make a great alternative to enjoy instead of chicken or beef on meatless monday!

Immune Boosting Foods: Mushrooms

4. Fermented Foods

Fermented foods contain live bacterial cultures that help your digestive system to break down foods, and that also have a role in supporting your immune system. A few of the most popular fermented ingredients include kimchi, sauerkraut, miso, and tempeh, along with beverages like kefir and kombucha.  Yogurt is also a great option, however since dairy is the most common food sensitivity I see for patients in my practice, I suggest choosing a dairy-free coconut or nut-based yogurt option instead.  

Immune boosting fermented foods help to replenish your digestive tract with beneficial, immune-supportive bacteria.  Since 70% of your immune activity is located in your gut, making sure that your gut-health is in tip top shape is a key priority when it comes to boosting your immune system!


5. Fresh Herbs and Spices

Yes, taking oil of oregano as a supplement is a potent antimicrobial and antiviral remedy.  However, so is consuming fresh herbs themselves! Do you ever use fresh herbs in your cooking, like oregano, rosemary, thyme and sage?

Fresh herbs are high in volatile oils, which are oils containing hundreds of potent natural chemicals that can help boost your immune system.  

How should you incorporate fresh herbs and spices into your cooking?  It’s easy! I love using fresh basil or cilantro in my salad dressings, adding fresh rosemary to roasted vegetables, and sprinkling thyme on top of a delicious homemade stew

I use fresh herbs as a staple ingredient in my Elimination Diet Meal Plan program recipes, along with many other immune boosting ingredients like garlic, ginger, mushrooms and pumpkin seeds.  This program is a fabulous way to boost your immune health, while also identifying if there are particular foods that have been dragging down your health and energy!

Fresh Herbs and Spices

6. Colourful Fruits and Veggies

Aim for your plate to include all colours of the rainbow, and you’ll be very likely to have a healthy immune system!  Colourful veggies are rich in phytonutrients, vitamins and antioxidants that support healthy immune function. Each of the various pigments contain different natural chemicals, which carry diverse health benefits! 

In regards to immune-health, one of the best colours to include are bright orange veggies, which are great sources of beta-carotene.  Carrots, sweet potatoes and winter squash are all great ways to fuel your body with all of the beta-carotene required to power-up your immune system! 

Colourful Fruits and Veggies

7. Foods That Are High in Zinc

As a mineral, zinc is crucial for the healthy function and development of immune cells.  Additionally, an important immune modulating hormone, thymulin, relies on adequate levels of zinc in order to function. 

The best food sources of zinc include meat, shellfish (especially oysters), seeds like pumpkin or hemp, and nuts (especially cashews).  Although nuts are a good source of zinc, they can also be common food sensitivities. Since consuming foods that are triggering your immune system depletes your body’s resources, identifying if you have food sensitivities is an important element of personalizing your immune-boosting diet!

Foods High in Zinc

8. Brazil Nuts

Brazil nuts are the highest food-source of an important immune boosting mineral, selenium, which has been studied to be vitally important to our immune systems ability to ward off viruses like the coronavirus.  Studies have also demonstrated that those who are deficient in selenium (and other minerals) are at higher risk of certain viruses mutating into more pathogenic strains.

You don’t need a lot of selenium to support healthy immune function, and since brazil nuts are so plentiful in this mineral you only need to consume 2-4 nuts per day for adequate intake.  Brazil nuts can be thrown into a smoothie, enjoyed in a trail mix, or chopped and sprinkled on a salad. It’s important to note that selenium can be toxic in excess quantities, so please speak with your naturopathic doctor to ensure your intake is sufficient, but that you don’t accidentally consume selenium in excess. 

9. Foods High in Vitamin C

Vitamin C is vital to healthy immune function!  Thankfully, if you’re eating a healthy diet filled with fruits and vegetables it’s easy to obtain adequate Vitamin C. The benefits of this nutrient include that it supports healthy immune barriers that keep viruses and bacteria out (where they belong!), and that it enhances the activity of your most important immune cells. 

The best food sources of vitamin C include citrus fruits, strawberries, kiwis, kale, broccoli and bell peppers.  Although citrus and bell peppers provide your body with its required vitamin C, they can also be common food sensitivities.  Since consuming foods that trigger your immune system is NOT helpful to prevent you from catching a cold or flu, identifying your food sensitivities is an important element of personalizing your immune-boosting diet!

Immune Boosting Foods: Vitamin C

3 Things to Avoid or Minimize for a Healthy Immune System:

1. Refined Sugars, Empty Carbohydrates, Sweetened Beverages and Processed Foods

Focus on taking in more of the foods that FUEL your body, and work to minimize those that spike your blood sugar and drive inflammation without delivering the vitamins, minerals and antioxidants that are so vital to your immune health.  The worst culprits for this include most conventional baked goods (cookies, cakes, twinkies, etc…), soda pop, candies, and anything made with refined white flour (like white buns and breads). Not only do excess carbohydrates and sugars crowd out essential nutrients, but they also directly impair your immune function

Thankfully this doesn’t mean you can never enjoy dessert, but the key is to choose recipes that use real, whole food ingredients with minimal added sugars!  A few delicious options from the Healthy Life Redesign blog include my dairy-free Lemon Blueberry Mini-Cheesecakes, Peanut Butter Oatmeal Chocolate Chip Cookies, and Maple Walnut & Banana Chocolate Chip Muffins.

Maple Walnut & Banana Chocolate Chip Muffins

2. Alcohol

Alcohol impairs our immune system because of its effects on our digestive tract and respiratory systemSpecifically, alcohol has damaging effects on the gut microbiome, as well as the health of our gastrointestinal cells and immune cells.  Similar effects occur in our lungs, and alcohol intake may increase the risk of respiratory infections, including pneumonia.

Additionally, alcohol intake negatively affects the quality of your sleep and decreases how much time is spent in restorative REM sleep.  All-in-all, decreasing your alcohol intake is one of the many things you can do to help support your immune system!

Love having something to sip on?  Try replacing some of your usual alcoholic beverages with a tasty virgin Strawberry-Mint Spritzer from the Healthy Life Redesign blog!

3. Food Sensitivities

Have you considered there could be “healthy” foods in your everyday diet that are directly triggering your immune system, therefore depleting your immune resources and also directly causing inflammation?  These types of reactions are referred to as food sensitivities, and helping my patients to identify their food sensitivities has become one of the most important aspects of my practice as a naturopathic doctor.

Food sensitivities are caused by a delayed immune reaction that involves antibody production against the proteins in certain foods.  Symptoms triggered by food sensitivities can include fatigue, brain fog, bloating, digestive upset or irregularity, headaches, joint pain, nasal congestion, acne and eczema.

Food sensitivities can result from a number of different food triggers, and an elimination diet is the best way to identify which foods are fueling your body, versus those that are dragging down your health and immune function.  To learn more, download my free eBook “A Naturopathic Guide to Identifying your Food Sensitivities”.


I hope these immune boosting foods help to keep you healthy and feeling your best!  By following the guidelines I’ve discussed above you’ll not only be boosting your immune system, but you will also be supporting healthy hormone balance and optimal energy. Many of these immune boosting foods are staples in my Elimination Diet Meal Plan online program, which is a great way to support your immune health and reduce inflammation, while also discovering how to best personalize your diet!  

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Elimination Diet Meal Plan

Immune Boosting Foods to fight the coronavirus

About the Author

Dr. Kimberley O'Brien


Dr. Kimberley O'Brien is a Naturopathic Doctor in  Nelson, BC with expertise in the treatment of digestive disorders, fatigue and hormone imbalances.  She is the founder of Healthy Life Redesign and creator of the Elimination Diet Meal Plan and the Real Food Recharge online programs.  Her mission is to help you own your health and live a life you love!

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