A Functional Medicine Expert’s Guide To Beating A Cold + Boosting Immunity

The Brain-Immune Axis

Your brain-immune axis is just what it sounds – a direct connection between the brain and the immune system. This axis is responsible for the link between stress and autoimmunity. For example, I have patients who started having severe immune dysfunction and autoimmune conditions following a head injury in a car accident. But why? One study (1) in the Journal of Neuroimmunology found that the cerebellum played a substantial role in modulating helpful immune cells.

Similarly, a study (2) in the Journal of Nuclear Medicine found, via brain mapping, the cerebellum playing a role of attempting to activate immune function in people with cancer! In addition to the cerebellum, your brain’s cerebral neocortex has been found (3) to be another key player in the brain-immune axis.

The Gut-Brain Axis

The communication between your microbiome and brain (gut-brain axis) is pivotal for overall health. Your gut is even referred to as your second brain, and physically they actually resemble each other and both were formed from the same fetal tissue while you were growing in your mother’s womb.

Around 80% of your immune system is found in the gut, and 95% of your serotonin, the feel-good neurotransmitter, is made and stored in the intestines. You can see that as the gut affects the brain, the opposite is also true. For example, the brain has been shown (4) to regulate gut mucosal immunity.

Tools To Support Your Immune System

While everyone is different, now that you understand the foundations of a healthy immune system, these are my favorite ways to help you amp up your immunity, naturally:

1. Support healthy methylation pathways

Methylation is sort of an antioxidant recycling process in your body, and it’s needed for optimal brain and immune health. Proper methylation produces your body’s top disease-fighting antioxidant glutathione. When your glutathione levels are low, so is your immune function. Things that deplete glutathione are:

• Toxic exposure
• Antidepressant medications
• Birth control pills
• Diabetic medications
• Antacid medications
• MTHFR gene mutations

I gauge methylation function in patients by running a lab called homocysteine. Homocysteine is supposed to be converted to glutathione via methylation. If homocysteine levels are high, methylation isn’t functioning well. Everyone should have this test run.

Homocysteine levels above 7 UMOL/L have been shown (5) to cause brain inflammation, destruction of the blood-brain barrier, and decreased immune health. The good news is that in the presence of methyl-donors like vitamin B6, homocysteine is converted to glutathione.

2. Optimize your vitamin D levels

The sunshine vitamin is crucial for brain and immune health because it is responsible for many different brain-immune pathways. (6) Low levels are linked to both autoimmune conditions and poor immune health.

Optimal vitamin D levels should be around 60-70 ng/mL for most people, especially those with autoimmune conditions.

3. Drive-down inflammation 

Chronic inflammation is one of the major underlying culprits of chronic disease, but healthy inflammation levels fight off disease. To support healthy inflammation levels, it is essential to support your brain’s neurotransmitter, acetylcholine. Healthy acetylcholine activity has been shown (7) to produce optimal nitric oxide balance. Nutrients like huperzine A (8) and adenosine triphosphate have been shown (9) to activate this pathway. Providing my patients with condition-specific amounts of these nutrients helps support this brain function.

4. Improve microbiome health

For a healthy immune system, you need to have a healthy microbiome, and conditions associated with dysbiosis, or an unfavorable balance between beneficial and pathogenic bacteria (such as SIBO and leaky gut syndrome) can drastically suppress healthy immune function.

5. Eat more detoxing food medicines

An overload of toxins can put stress on your immune system. I always make conscious choices to avoid toxins as much as possible, so when it comes time to detox I need to go to the next-level. Parsley, cilantro, dandelion tea and blueberries are all easy to incorporate throughout my day. Parsley and cilantro get added to smoothies or salads and blueberries are eaten by the handful. You can always find me with a cup of tea in my hand so I’ll switch out my typical green tea with dandelion to take advantage of its B-vitamin content to help support my detoxing methylation pathways.

6. Add in adaptogens

Whenever I need a health pick-me-up adaptogens are the first thing I turn to. These natural plants and herbs provide support to different areas of your body in order to restore balance. Some are my favorites include:

• Ashwagandha: Often used to restore the immune system after being sick
• Maca: Loaded with vitamin C
• Astragalus: Antiviral and antibacterial

7. Target your supplements

My normal diet consists of whole food sources such as wild-caught seafood, grass-fed beef, a variety of vegetables, healthy fats, and some fruit. I typically like to use medicine as my food but sometimes supplements can provide a beneficial boost.

• Vitamin C: This is the ultimate immune booster. Studies have shown (10) it can reduce symptoms by up to 30% with a typical daily dose between 1,000 and 4,000 mg.
• Zinc: When taken with vitamin C it can increase vitamin C’s immune benefits. It is responsible for increasing white blood cells and helping to fight off infections. Research shows around 75 mg can help reduce (11) the length of a cold.
• Echinacea: This herb can shorten (12) the length of your cold.

8. Increase your immune-supporting foods

The second I feel a cold starting I reach for Manuka honey. This honey comes straight from New Zealand and its antimicrobial properties are out of this world. Adaptogenic mushrooms are another favorite of mine. Chaga (13) and Turkey tail (14) both work to bring balance to the immune system. If you are dealing with a virus like the flu Chaga works great for that as well due to its antiviral properties. If you don’t like mushrooms you can get them in powder form to put in tea and smoothies but I personally love to eat them as a side with my meals sautéed with garlic and onions.

9. Gargle with sea salt water

Sea salt is more than just a meal-time seasoning. It is actually a fantastic anti-inflammatory (15) tool that can be used to ease a sore throat. I usually mix 1 teaspoon sea salt with 8 ounces of water and gargle for at least 30 seconds which helps to break up mucus and get rid of bacteria from the throat. There’s a reason why the American Journal of Preventive Medicine found a 40 percent decrease (16) in upper respiratory infections in those who gargled with salt water.

10. Cook with ginger

Next time you’re at the grocery store, pick up some fresh ginger. Not only is it one of the most affordable herbs, fresh ginger has also been shown to prevent the human respiratory syncytial virus (HRSV) (17) from attaching to cells and forming plaque in the airways. This is likely thanks to gingers many active compounds, including terpenoids, gingerol, and flavonoids, which work together to fend off the development of pathogenic biofilms. You can juice ginger, make fresh ginger tea, or incorporate it into recipes.

11. Add in cinnamon

Cinnamon is one of my favorite herbs; not only can it help stabilize blood sugar, but it can also work as a next-level immune system supporter. I often suggest cinnamon to my patients with blood sugar issues due to its ability to help stabilize blood sugar levels, but it also works as a next-level immunity supporter thanks to its high antioxidant content (18), which protects cells from damage. One study even showed that cinnamon can block the powerful flu strain (H7N3) (19) from entering the body’s cells. You can buy cinnamon tea, take it in a capsule, or sprinkle ground cinnamon on your yogurt, oatmeal, or into your smoothies and coffees.

12. Get some sunlight

We may be under “stay at home” orders, but that doesn’t mean we should skimp on a daily dose of sunlight if at all possible. Sunlight has demonstrated incredible healing properties; in fact, during the 1918 flu pandemic, health experts found that putting sick patients out in the sun helped deactivate the virus (20). We’re not exactly sure why sunlight is so healing, but it could have something to do with its influence on vitamin D production, which plays a role in dozens of pathways that are needed to fight off various illnesses. Not to mention, sunlight helps our body’s natural circadian rhythms, which emerging research suggests can regulate our inflammatory response (21) to viruses.

13. Book a sauna session

We all know that saunas are incredibly relaxing and comforting. But did you know that researchers have started studying the relationship between regular sauna sessions and decreased risk of respiratory diseases like pneumonia? It’s true. If fact, one study showed (22) a direct relationship between the number of sauna sessions per week and decreased risk.

So what explains these benefits? One theory is that saunas activate heat shock proteins (23) in our bodies. These proteins are produced naturally in response to stressful conditions (such as intense heat or cold) and work to increase the antiviral activity of prostaglandins (24), which are a group of lipid compounds that can inhibit RNA-based viral replication. This can slow — or even halt in some instances! —  the ability of a virus to develop and grow in your body.

14. Enjoy some fresh air

We already know that sunlight was helpful during the 1918 Spanish flu pandemic, but doctors also found that open-air therapy dramatically improved the health of patients. This is something referred to as the “Open Air Factor,” where fresh air is thought to help to kill off bacteria and the influenza viruses compared to indoor air, both during the day and during the night. Decades later in the 1960s, the Ministry of Defense confirmed the therapeutic benefits of fresh air (25).

15. Turn to essential oils

I regularly diffuse oils in my home and functional medicine clinic. The use of oils for healing dates back thousands of years. When I feel a cold creeping up I go a little crazy with some specific ones:

• Eucalyptus: Not only does this oil smell wonderful it helps clear up any congestion. It can be great diffused or rubbed on your chest. It is also antimicrobial. (26)
• Tea Tree: This is a great multi-purpose antimicrobial, antifungal, (27) and antiviral oil.
• Frankincense and myrrh: There’s a reason why the wise men chose these to gift to the newborn baby Jesus. Together, they have intensive antimicrobial properties. (28) And bonus, they smell amazing so I love  use them on my neck and arms even when I am not feeling sick!
• Peppermint: Great for easing nausea, alleviating headaches, and clearing up congestion.
• Lemon: This oil is very cleansing and can help with braking up mucous and relieving stomach pains.

Note: You can purchase these oils online or in stores. When using these oils make sure to read the bottle for key areas to put the oil for the best effect and for the amount to use, dilution, whether to take them orally and other important information. The brands we recommend would be either Young Living or DoTerra which are both certified therapeutic grade.

16. Sip on bone broth

Growing up, it was likely that you were given chicken noodle soup when you were sick and there’s a reason. Bone broth is filled with nutrients like glucosamine, glycine, gelatin, and other minerals that help to heal your gut which is especially restorative after having a stomach virus like the flu. As Hippocrates says “all disease begins in your gut,” so it is essential to give your digestive system the nutrients it needs to get back to feeling 100%.

Support Your Immune System With Tea

Tea is another powerful tool in the fight against the common cold. Each variety — including white, green, black, oolong, and herbal — have beneficial ingredients that can support your immune system, which can need a little extra support in the winter.

When I feel a cold coming on, I reach for the following varieties, which I know will build up my immune system to fight off illness completely — or at least reduce pesky symptoms like sinus congestion or a sore throat and cough.

1. Licorice tea

Licorice isn’t just a candy — it’s an immune-boosting herb, too! Licorice is very commonly used in traditional Chinese medicine because its flavonoid content helps boost immune health. It’s even been shown to fight off various viral and bacterial infections (29) such as MRSA.

2. Echinacea

Echinacea flower is found in most immune-support supplements; in fact, it’s one of the most common ingredients in the cold and flu aisle of the pharmacy and is known for both its antiviral and antibacterial properties (30).

I prefer to take echinacea in tea form, so I can sip it throughout the day. You can also add honey, which will give it some sweetness and is a powerful ingredient in its own right. In fact, studies have shown (31) that honey is as effective as the dextromethorphan, a common cough suppressant in over the counter medications.

3. Hibiscus

This bright red herbal tea is mostly found iced, but you can use drink it cold or hot to fend off the seasonal sniffles. It’s got a high content of vitamin C, which studies have shown can reduce cold symptoms (32) by up to 30%.

4. Ginger

The common cold is often accompanied by some sort of digestive distress. Enter: ginger, the ultimate remedy for nausea and an inflamed gut. Ginger is so powerful that studies have even shown (33) that it can ease the nausea associated with pregnancy and chemotherapy side effects. I love sipping on some ginger tea — hot or iced — throughout the day when I’m not feeling my best.

5. Elderberry

You may have heard of elderberry syrup or gummies, which are often used for immune support. That said, you might not know that it also comes in a tea form that contains significantly less sugar. Elderberry is famous for its antimicrobial and antiviral properties (34); it has even been shown to be a viable remedy against both pathogenic bacteria and the flu virus!

6. Chamomile

Chamomile is a go-to ingredient for sleep, so I like to keep it around for when I’m feeling under the weather and sleep is a top priority. I typically sip a cup about 30 minutes before bed to make sure I get some restorative sleep. Expert tip: The longer you brew an herbal tea, the more powerful it will be. Let your tea steep — don’t forget to use a lid to make sure the essential oils don’t escape! — for at least five minutes before you enjoy it.

7. Lemon Balm

Lemon balm doesn’t just smell like heaven, it has tons of vitamin C to help you fend off bugs that threaten to keep you home from work or school. It also boasts a light, sweet lemon flavor and is a great natural sleep aid (35). You can find lemon balm in many tea blends and also on its own.

8. Red Elm Tree

Red elm tree, which is also known as slippery elm, is used in many cough drops and teas because it forms a substance called mucilage when mixed with water. Mucilage helps coat the throat and has been traditionally used to treat common symptoms of laryngitis and other respiratory problems, like coughing. It also contains bioflavonoids, tannins, calcium, and vitamin E, all of which provide their own unique health-boosting properties. Red elm tree is the perfect addition to your winter wellness routine, especially when you’re feeling run down.

9. Peppermint

If you’re suffering from chest or sinus congestion, peppermint tea is the way to go. This type of tea clears the sinuses and opens up your nasal passages because of its menthol content — an ingredient that naturally soothes your sinuses (36) and opens up nasal passages. As an added bonus, it may also help reduce any nausea or stomach upset you may be experiencing.

10. Pu-erh

This classic Chinese tea is made from the Camellia sinensis plant, which means you can find it in green, black, or white tea form. Research has pointed (37) to Pu-erh having antibacterial properties, which means it can help fight off harmful bacteria.

So next time you are feeling under the weather, grab your largest mug, your coziest blanket, and curl up with one of these cold- and flu-fighting teas!

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