6 Superfoods to Supercharge Your Immunity: Nature’s Defense

September 3, 2024

When it comes to keeping your immune system in peak condition, especially during those back-to-school months when flu season is lurking, the foods you choose can make all the difference.

Imagine harnessing the power of nature to protect yourself and your loved ones from the wave of seasonal bugs. It’s not just about adding more greens to your plate; it’s about selecting the right superfoods that work in synergy to supercharge your immune defenses.

In this article, you’ll discover six potent, nutrient-dense foods (that you can easily find at your local farmer’s market, grocery store, or online health shop) that I’ve handpicked for their immunity-boosting properties. These aren’t just any superfoods—they’re tailored to give your body the best shot at fending off the usual suspects, from the common cold to the more stubborn viruses that seem to make the rounds this time of year.

Consider this your personal guide to building an invisible shield against illness. The simple, budget-friendly ingredients you’ll dive into are packed with vitamins, minerals, and antioxidants designed to bolster your immune system, ensuring that you and your family stay healthy and resilient. Whether you’re packing lunches or planning your meals, these foods will play a key role in keeping everyone in your household feeling their best.

So, if you’re ready to take control of your health and arm your body with the ultimate defense against seasonal sickness, read on. This is more than just a list—it’s a strategic approach to nutrition that prioritizes your well-being, helping you stay ahead of whatever the season throws your way.

Ben Greenfield’s 6 *Game-Changing* Foods, Plants, & Herbs to Boost Your Immunity This Flu Season

1. Thieves Oil 

An old tale from the fourteenth century recounts how, amid the bubonic plague ravaging Europe and Asia, four thieves gained infamy for looting the possessions of plague victims.

Remarkably, despite their constant exposure to the highly infectious disease, the thieves never contracted the plague.

According to lore, after they were caught and charged, the court magistrate offered them a deal: in exchange for a reduced sentence, they could share their secret to immunity from the plague. The thieves took the deal and told of a blend of medicinal herbs they consumed daily, specifically cloves, lemon, cinnamon, eucalyptus, and rosemary (you can pick most of these ingredients up at Thrive Market). Hundreds of years later, this blend of aromatic herbs was proven to be a potent way to kill airborne bacteria, enhance the activity of white blood cells, and increase lymph fluid circulation.

How to Make Your Own Thieves Oil

Whether or not the story is true, the “four thieves” remedy was developed into an herbal formulation in Europe between 1413 and 1722. Several variations of this formulation have been passed down through the years. Thomas Jefferson is said to have fancied a version that consisted of vinegar spiked with lavender, rosemary, sage, wormwood, rue, mint, and garlic to keep his presidential body infection-free. In contrast, the Scientific American Cyclopedia of Preparations gives this formula:

• 4 oz dried rosemary tops
• 4 oz dried sage
• 2 oz dried lavender
• 5 oz fresh rue
• 1 oz camphor dissolved in vinegar
• ¼ oz sliced garlic
• 1 oz bruised cloves
• 1 gallon of strongly distilled wine vinegar

To make a batch of immunity-boosting thieves oil, you’ll need to:

1. Digest your concoction: Allow your mixture to sit and blend together for 7 or 8 days.
2. Occasionally agitate it: Periodically shake or stir the mixture to thoroughly combine all ingredients.
3. Pour off liquor: After the infusion period, separate the liquid part of the mixture from any solid residue.
4. Press out the remainder: Extract the remaining liquid from the solid components that were left behind after pouring off the initial liquid. This might involve pressing or squeezing.
5. Filter the mixed liquids: Finally, filter the combined liquid to remove any remaining solid particles and to ensure a clear, purified final product.

For more information on fresh superfoods and tinctures that fight illnesses and increase your immunity, I recommend checking out my podcasts with the founder of Kauai Farmacy, Doug Wolkon, which you can find here, here, and here.

2. Elderberry

One of the highlights of my year is when the old elderberry tree in the forest behind our house comes into full production and creates oodles of elderberries, which my wife collects, ferments, and turns into a dark, dense, immune-boosting elderberry wine.

Elderberry teas, tinctures, and supplements are all excellent options to have on hand in your medicinal pantry.

The Health Benefits of Elderberry

The anthocyanins in elderberries have been shown to have potent immunostimulant effects. In fact, a 2016 study showed that elderberry supplementation can vastly reduce the duration and symptoms of colds in air travelers. Another study found that when the elderberry extract is used within the first forty-eight hours of the onset of flu symptoms, it shortens the duration of symptoms by an average of four days.

Because of its sweet, tart, and refreshing taste, elderberry juice is an excellent alternative to elderberry wine, especially if you don’t have time to make the wine. Good brands include River Hills, Biotta, Biona, and Wyldewood Cellars—all of which have a tart and tannic flavor, with a mild sweetness.

An elderberry tincture is another good option. There’s a DIY elderberry tincture recipe in my book Boundless Kitchen. Effective doses of elderberry extract range from 600 to 900mg per day.

*As a word of caution, the elderberry plant is POISONOUS aside from the berries, so should you choose to prepare an elderberry treatment yourself, be sure to use only the berries and to prepare them properly via a process such as fermentation.

3. Bone Broth

There is a reason why native peoples have been consuming bone broths for thousands of years, why your grandmother’s chicken soup always seemed to cure what ailed you, and why there’s a South American proverb that claims “bone broth raises the dead.”

Whether bone broth is as magical a healing aid as it is touted to be remains to be proven by robust research, but nonetheless, there are numerous health benefits to simply drinking liquid that has been simmering with the marrow and joint bones of beef, chicken, lamb, and even fish for twenty-four to forty-eight hours.

The Nutritional Benefits of Bone Broth

Bone broth contains substances that are vital to the innate immune system, such as the amino acids arginine (which is critical for the immune system and liver function), glutamine (which assists with cellular metabolism), and glycine (which aids in glutathione production and improves sleep quality). The marrow in bone broth contains lipids called alkylglycerols that are crucial for the production of white blood cells. These same alkylglycerols also appear in colostrum and have been shown to control the growth of cancer cells. According to research by Dr. Matthias Rath, the collagen in bone broth may also prevent cancer tumor metastasis, and the gelatin in bone broth is beneficial for autoimmune diseases related to a leaky gut. The glycosaminoglycans found in bone broth can similarly help restore a healthy intestinal lining, while the chondroitin sulfate in bone broth has both anti-inflammatory and immunoregulatory effects.

Proceed with caution if you purchase packaged bone broth, as not all bone broth is created equal. Almost every company selling bone broth online—even the ones using grass-fed and organic ingredients—is freezing their broth and shipping it with lots of dry ice and harmful Styrofoam containers.

Furthermore, many broths don’t even list bones on the ingredients label. If bones aren’t mentioned, the broth likely won’t contain vital nutrients from bone marrow, such as collagen, immune-boosting alkylglycerols, or omega-3 essential fatty acids. For optimal quality, select broths made with high-quality bones from beef, chicken, or fish, preferably sourced from organic, pasture-raised, or wild-caught animals.

Making Bone Broth at Home

It’s simple to make your own bone broth:

• Just place the bones left over from chicken, turkey, beef marrow bones, oxtails, beef feet, or beef neck bones (many of these odd cuts are available for a very good deal from your local butcher) in a stockpot or slow cooker and cover them with water.
• Add a splash of apple cider vinegar to help extract minerals from the bones.
• Optionally, include aromatics like onions, garlic, carrots, celery, and herbs for added flavor.
• Bring the mixture to a boil, then reduce the heat to a simmer and let it cook for at least 12 to 24 hours, or even longer for richer flavor and increased nutrient extraction.
• Skim off any foam or impurities that rise to the surface during cooking.
• Once done, strain the broth to remove the solids, then let it cool before storing it in the refrigerator or freezer.

Recommended Bone Broth Brands and Recipes

Although it’s best to make your own bone broth at home, one good, shelf-stable, done-for-you brand is Kettle & Fire. They maintain strict standards to deliver bone broth made from the bones of cattle that are humanely raised without antibiotics or hormones and are

100 percent grass-fed and grass-finished.

For a nourishing morning breakfast, you can experiment with Dr. Thomas Cowan’s healing broth recipe. The following is adapted

from his excellent book Cancer and the New Biology of Water:

• Heat a generous amount of grass-fed ghee in a saucepan over medium heat, then add 1 to 2 tablespoons of turmeric powder and stir until it dissolves.
• Add 3 to 7 vegetables of choice (the sprouting mixes from The Sprouting Company are my favorites, especially the high-protein mix) and/or a blend of vegetable powders and sauté until the vegetables are soft.
• Next, add 1 to 2 cups of bone broth. Turn the heat down to low and simmer for 1 to 2 minutes, then stir in a generous portion of powdered vegetable extract.
• Finally, ladle the broth into a bowl and add 1 tablespoon each of naturally fermented miso and natto.

For this recipe, I recommend a vegetable powder blend like ashitaba, burdock, low-oxalate greens, or the savory Threefold Blend of powdered vegetable extracts from Dr. Cowan’s website.

Considerations for Histamine Sensitivities

Finally, note that those with histamine sensitivities or mast cell issues may need to proceed with caution when it comes to bone broth and fermented foods—pay close attention to any symptoms you experience after eating them.

4. Fermented Foods

If you open my refrigerator, you will see that the entire top shelf is chock-full of mason jars packed with fermented vegetables—from sauerkraut to pickles to kimchi and beyond—along with homemade coconut yogurt, water kefir, dairy kefir, natto, miso, and plenty of other fun fermentation products.

My lunchtime salad and side dish at dinner often include a heaping tablespoon of these ferments, such as sauerkraut or kimchi, a dollop of yogurt, a fermented pickle, a teaspoon of miso, or a glass of my wife’s homemade kombucha or kefir.

When I began incorporating these types of fermented foods and probiotics into my diet, my frequent seasonal colds dwindled (I was getting sick once a year rather than once a month!). By supporting my gut bacteria, I was drastically improving my immune system.

The Power of Probiotics and Gut Health Support

It is estimated that three-quarters of your immune system resides in your gut. Indeed, immunity begins with the bacteria in your digestive tract, as these creatures play vital roles in nutrient absorption, mucosal barrier function, support of gut lymphoid tissue, and immune function.

For example, take lactic acid bacteria, also known as Lactobacillus paracasei, which is found in naturally fermented foods like sauerkraut and yogurt. It produces the enzyme lactocepin, which is able to destroy immune system messengers called chemokines. In a healthy gut, chemokines guide white blood cells to an infection, but in individuals with inflammatory bowel disease, they can exacerbate an autoimmune response. Consuming sources of lactic acid bacteria can thus reduce autoimmune symptoms.

Another strain of bacteria, the probiotic Bifidobacteria, secretes gamma-aminobutyric acid. Macrophages, which are immune cells that engulf bacteria and virus-infested cells, contain butyric acid receptors that, when activated by the acid, can reduce the production of inflammatory compounds. The cell walls of Bifidobacteria also contain a dipeptide that activates the synthesis of lymphocytes, which are immune cells that produce antibodies and are responsible for acquired immunity. Scientists have also examined the effect of kefir, which is probiotic-rich fermented milk, on the immune systems of rats. The rats were given kefir daily for twenty-eight days and then injected with a cholera toxin. The rats that had been eating a daily dose of kefir exhibited significantly higher antibodies to the toxin than the control group.

Strategies for Restoring and Protecting Gut Biodiversity

To get more details on supporting natural, healthy gut flora, I recommend combining a high intake of a wide variety of fermented foods with daily use of gut-nourishing compounds like colostrum, L-glutamine, or the supplement ION* (you can use code BEN15 to save 15% off your first order).

Over the last sixty years, there has been a steady loss of biodiversity in the gut membrane’s bacterial ecosystem, and a large part of this is due to factory farming, processed foods, and widespread antibiotic use. This loss of biodiversity has left our gut membrane walls vulnerable. But the most potent of the common causes of damage to the gut wall in our diet is glyphosate—an ingredient in weed killers—because it triggers the activation of a protein called zonulin. Zonulin is produced in the gut, where it opens the tight junctions between cells in the intestinal lining, then circulates systemically and can open the blood-brain barrier, kidney tubule systems, and blood vessel walls.

ION* is a liquid supplement that delivers bacterial metabolites to promote a healthy firewall of tight junctions in the gut wall and blood-brain barrier and rapidly increases the production of the enzymes that break down zonulin. Although I always buy organic, because of the widespread prevalence of glyphosate toxins even in organic food, I take ION* several times per day. 

5. Mushrooms

Mushrooms are a nutritional powerhouse, providing B vitamins, minerals, fiber, protein, antioxidants, beta-glucans, and other bioactive molecules that fight harmful bacteria, viruses, and toxins.

Many mushrooms are also immunomodulators that stimulate the immune system’s defense mechanisms.

The Benefits of Shiitake Mushrooms

For example, one study found that daily consumption of 5 to 10g of shiitake mushrooms for four weeks significantly improved immunity and lowered inflammation. Shiitake mushrooms also exert antitumor activity and, when used in conjunction with chemotherapy, have been shown to prolong survival time, restore immunological parameters, and improve quality of life. The American College of Nutrition has found that shiitake mushrooms can improve the efficiency of the immune system, improve gut immunity, and decrease inflammation, and lab tests on human cell lines show that shiitake mushrooms can prevent malignant tumor growth by signaling tumor cells to burst in a process called apoptosis. Lastly, shiitake mushrooms have potent antimicrobial properties, making them effective natural antibiotics. Amazingly, one study showed that shiitake only killed disease-causing microbes, leaving beneficial bacteria unharmed (in contrast, prescription antibiotics kill off both beneficial and bad bacteria in your body).

Immunomodulating Properties of Maitake and Cordyceps Mushrooms

Maitake mushrooms are also powerful immunomodulators that stimulate the immune system’s defense reaction through enhanced cytokine production, phagocytosis, and NK cell activity. Cordyceps, which is a fungus that lives on certain caterpillars in the high mountain regions of China, also exhibits potent antitumor effects and immunomodulating effects. Studies have shown that cordyceps can help improve the body’s innate immune function, and it’s so effective in modulating immunity (which involves both improving an immune reaction to an invader or tumor and reducing an immune overreaction like asthma) that it has even shown benefits in studies on people with severe asthma. Evidence also suggests that cordyceps can help autoimmune issues and decrease the number of harmful bacteria in the gut.

The Immune-Boosting Power of Turkey Tail Mushrooms

The turkey tail mushroom contains bioactive compounds called beta-glucans, which can stimulate the immune system by enhancing macrophage and natural killer cell function. Studies also suggest that beta-glucans can help the immune system slow the growth of tumors and protect the body from the effects of cancer-causing compounds. Turkey tail also contains a high number of prebiotics, which feed the good bacteria in your gut and support immunity.

Tremella: A Lesser-Known Mushroom with Potent Benefits

Another little-known but highly effective mushroom is the tremella, which is rich in vitamin D and fiber, and contains specific compounds that protect the liver. Research suggests that tremella mushrooms can help the body fight infections, and in ancestral medicine, it has long been used as an immune tonic.

Chaga: The King of Medicinal Mushrooms

Finally, there’s one of the most powerful mushrooms for immune systems, the “king of medicinal mushrooms”: chaga. Chaga has an abundance of beta-glucans, and research has also shown that it activates immune cells responsible for combating cancer growth. Chaga increases the production of immune cells IL-6 and lymphocytes, which can help increase the ability to fight pathogens. Other compounds in chaga help the immune system to differentiate between the body’s cells and foreign cells. Chaga reduces immune hypersensitivity and even reduces the risk of cardiac shock from severe allergic reactions. Chaga also has antiviral properties and can help fight off viral infections—it may even reduce the ability of HIV to replicate and prevent herpes and Epstein-Barr viruses from infecting new cells and replicating.

Enhancing Immunity with Mushroom Modulation and Blends

Most of these mushrooms help regulate cell-mediated and adaptive immunity via the process of modulation—both potentiating and suppressing the immune system similar to the way that an adaptogen can modulate endocrine and hormonal balance.

One of my favorite ways to get a daily dose of immune-boosting mushrooms is to use Four Sigmatic’s 10 Mushroom Blend, which includes a hefty dose of vitamin C (from rosehips), along with chaga, reishi, cordyceps, lion’s mane, shiitake, maitake, and a few other choice immune-boosting mushrooms. You can put a teaspoon of this blend in your morning cup of coffee or tea. Other good brands include Real Mushrooms, Cymbiotika, and Host Defense.

6. Bee Products

When it comes to creating compounds that support the immune system, bees can be a valuable resource.

You’re no doubt familiar with honey, but there are also three other immune-supporting bee products: bee pollen, royal jelly, and propolis.

The Truth About Real Raw Honey

Real raw honey stands in stark contrast to the fake, pesticide- and herbicide-laden, nutrient-poor honey you find in the average plastic honey bear at the grocery store. Raw honey has so many enzymes that it’s the only food in the world that never goes bad, and it’s full of minerals and antioxidants. In addition, honey contains minor amounts of the same type of bioactive components found in antioxidant-rich fruits and vegetables, including phenolic acid, flavonoids, α-tocopherol, ascorbic acid, proteins, and carotenoids.

The Antiviral Power of Manuka Honey

Honey also has potent antiviral properties and can speed recovery from viral infections. Manuka honey, a type of honey produced by bees that feed on the nectar of the tea tree, inhibits flu virus replication and has been shown to be more effective than the active ingredients in popular cough medicines at improving both cough and sleep quality in individuals with upper respiratory infections. Methylglyoxal (MGO) is the primary anti-flu component of manuka honey. When selecting manuka honey, look for the MGO label on the jar and choose a brand with an MGO content of 83 or above (the higher the MGO rating, the higher the level of antiviral activity of the honey).

Bee Pollen: Nature’s Nutrient Powerhouse

Bee pollen is one of the most nutrient-dense foods found in nature. It’s packed full of vitamins and minerals, and it has nearly a full spectrum of essential nutrients. Pollen is the colostrum of the insect world—it contains more protein per gram than any other animal-based food, as well as free-forming amino acids. Research suggests that bee pollen has potent antifungal, antiviral, anti-inflammatory, antimicrobial, anticancer, liver-protecting, and local analgesic properties.

Royal Jelly: The Elixir of Longevity

Royal jelly, secreted by glands in the heads of nurse bees, is the exclusive food of queen bees, who live about forty times longer than worker bees. Cleopatra used royal jelly on her skin regularly because of its regenerative and healing effects. Research suggests that nutrient-dense royal jelly may also support nerve health, mental acuity, and memory, and protect against nerve damage because of its high acetylcholine content. It’s certainly a superfood. It contains proteins, fatty acids, polyphenols, adenosine monophosphate, and hormones like testosterone, estradiol, progesterone, and prolactin.

Propolis: Nature’s Immune Protector

Finally, there’s propolis, which is the most potent of the immune-supporting compounds you can borrow from the bees. Propolis, taken from the Greek words for defense (pro) and city or community (polis), is known commonly as “bee glue” and is literally the immune protection for the beehive. Bees use propolis to seal holes and cracks in the beehive; it hardens the walls and even makes the inside of the hive aseptic. Studies on humans have shown that it has several applications in treating a host of diseases because of its antiseptic, antibacterial, antioxidant, anti-inflammatory, antifungal, antiulcer, antimycotic, anticancer, and immunomodulatory properties. It contains over three hundred natural compounds that have been shown to help immunity, and there’s evidence that humans have been using propolis to support health since 300 BC.

In my pantry, you’ll find royal jelly, propolis, bee pollen, and raw honey from Beekeeper’s Naturals; a selection of other local, raw organic honeys; and even a drinkable blend of royal jelly, propolis, bee pollen, and wasp extract from Vespa (which is also a keto-friendly fuel for athletes).

Incorporating these immune-boosting foods into your routine is a powerful step toward safeguarding your health during the flu season and beyond. Each food on this list offers unique benefits, from the protective properties of thieves oil to the gut-nourishing power of fermented foods. By making these nutrient-dense choices part of your daily diet, you can build a robust defense system that keeps illness at bay and supports overall well-being.

Strengthening Your Defense: Boosting Immunity for Flu Season and Beyond