Using Food As Medicine To Support Your Immune Health During The Coronavirus Pandemic

The outbreak of COVID-19 that has occurred in the last month has reinforced that there is nothing more important than investing in health and supporting community. Taking care of yourself and your neighbors are two essentials in the current situation. There’s something really special about the way that natural disasters bring out the best in humanity and also lead to pausing and reflecting on how to show up for yourself more fully. I understand that these are not easy times but I want to encourage you to make the most of them by re-prioritizing your health.   

The intention of this article is to provide you with an overview on how your immune system works, how you can leverage the power of food as medicine to optimize your immunity, and what to be cautious of when supplementing. Because COVID-19 is an emerging infectious disease, there are no randomized control trials that document how the Coronavirus itself interacts with certain nutrients. There are some speculations that are unfolding that I share in this article but the rest is focused on evidence-based and safe approaches to supporting a robust immune system and your body’s antiviral functions.

While developments of vaccines and testing are essential, let’s not lose sight of the power of what we have in the kitchen. Research shows that nutrition can help to upregulate your immune function and support your body’s ability to fight off pathogens. Micronutrients found in your diet play key roles at every stage of the body’s immune response. Also keep in mind that a nutrient-dense diet can shape not just your immune health but also your mental health through the gut-brain axis.

Building Resilience 

Both your immune and mental health are dependent on a strong and resilient microbiome. In fact, one of the main pillars of a healthy gut ecosystem is resilience. Being resilient speaks to your ability to stay healthy or recover quickly when exposed to a harmful bacteria, viruses or toxins. Resilience is not something that is built overnight. You build it with your daily practices: eating a nourishing diet, meditating or deep breathing to support your HPA Axis, moving your body and prioritizing sleep. These are the ingredients that help arm us with emotional and immunological resilience that we can count on in times of uncertainty. The more that you participate in these actions, the stronger your armor becomes. If you cannot afford a single supplement because of financial changes, focus on those daily practices that happen to be free.

The focus on optimizing your overall and immunological health is twofold: 1) lower your risk of getting Coronavirus and 2) improve your prognosis, if in fact you were to contract the virus. According to a paper published in JAMA on March 13, 2020, those that are most susceptible to contracting COVID-19, in addition to having less favorable outcomes, if in fact they do contract the virus, are older adults (>65 years old) and individuals with chronic underlying diseases such as hypertension and diabetes.

Approximately 1/3 of patients in the cohort that were diagnosed with coronavirus had comorbidities such as hypertension, diabetes, and liver disease. These comorbidities also put patients at a higher risk of less favorable prognoses. The paper found that within patients with coronavirus, there was a significantly associated risk of developing Acute Respiratory Disease Syndrome (ARDS) among older age adults (>65 years old), high fever, comorbidities (hypertension, diabetes), lymphocytopenia (low levels of white blood cells called lymphocytes), elevated inflammation markers (elevated high-sensitivity CRP and serum ferritin), and a few others. A letter to the Lancet also reported that in a study that included 140 patients who were admitted to the hospital with COVID-19, 30% had hypertension and 12% had diabetes. 

What does this mean? Those who did not have optimal health at baseline and had higher levels of inflammation were more likely to contract COVID-19 and upon diagnosis, were less resilient, increasing the risk of advancing to ARDS. When it comes to your health, you never know what you are training for. You never know when public health pandemics will occur. But regardless, you want to be as healthy as possible to increase your chance of survival. The only way to do that is by participating in daily practices to build health, endurance and resilience. 

Immune System 101 

Your first line of defense against foreign invaders includes your skin and all mucus membranes. This physically blocks pathogens from entering the body. Additionally, your body produces chemicals that help fight off bacteria, viruses, fungi, parasites and toxins through saliva, mucus, sweat and gastric acids. These allow the body to trap and remove or destroy foreign invaders. This physical barrier also can be found in the epithelial cells that line the gut microbiome and protect the epithelium from exposure to foreign invaders and help fight off pathogens. For optimal immune health, you need a strong lining of the gut (to prevent a leaky gut). Foods rich in zinc, vitamin A, omega 3 fatty acids, l-glutamine and vitamin D help to support epithelial barrier function.

Beyond the physical barrier, your immune system consists of two main branches: innate (non-specific and adaptive (acquired) immunity. Your innate immunity is the first line of defense that is non-specific, meaning it does not differentiate between pathogens. The body produces the same substances in response to all pathogens that are meant to attack and remove invaders. This includes your white blood cells (leukocytes), neutrophils, and macrophages.  

Your second branch is the adaptive immune system. This is the more specific part of your immune system that gets signals from the dendritic cells when the innate immune system needs backup support. This part of your immune system is antigen-specific, meaning it can differentiate between various types of pathogens, thanks to molecules that are found on the surface of pathogens called antigens. It has two main components: T lymphocytes and B lymphocytes, which also include memory cells that remember old pathogens (like chickenpox) and make the body more efficient if exposed another time. 

Before getting into ways to boost your immune support through food and nutrients, remember that optimizing your dietary intake of nutrients should never replace critical public health measure that will help you avoid the infection. These include washing your hands frequently with soap and water for at least 20 seconds, practicing social distancing and staying home in order to flatten the curve, and keeping your nasal passages moist with an all-natural saline

The Best Nutrients + Foods To Support your Immune Health 

Nutrients, phytochemicals and functional foods have been shown to have immune-regulatory properties that can enhance your immune system’s response and ability to attack and remove foreign invaders. This is what has prompted the field of nutritional immunology. Nutrients serve as the basic ingredients that help the immune system function at its best (in addition to meditation, sleep, exercise) and also decrease inflammation-mediated conditions. This in no way means that supplementation should replace focusing on a whole foods diet. It means that in addition to your whole foods, nutrient-dense diet, you may benefit from higher doses of certain nutrients to enhance your immune system. 

There is no argument that nutrient deficiencies cause impairment of the immune system. One explanation for why older adults are more susceptible to Coronavirus may be that with age, the body has greater needs for certain dietary components due to decreases in cellular functions. Below are the primary nutrients to incorporate into your diet and possibly, your supplement routine. Always check with your healthcare practitioner before reading information on the internet. 

1. Feed a Healthy Gut with Probiotic + Prebiotic Rich Foods

There is a close association between your gut microbiome and the maturation and development of the immune system because the gut has the largest collection of immune cells than anywhere else in the body. The gut associated lymphoid tissue (GALT) is the largest immune organ of the body and it resides in the gut microbiome. That means that the bacteria that live in your large intestine play a role in stimulating your innate immune response and protecting against pathogens. If you want to enhance your health, you must feed and nourish your gut.

This can be done through eating a well balanced diet that is high in dietary fiber, color and foods rich in prebiotics + probiotics. Prebiotic rich foods include organic apple cider vinegar, apples, asparagus, garlic, leeks, onions, lupini beans, unmodified potato starch and more. Probiotic rich foods include sauerkraut, kimchi, yogurt or almond yogurt. You may also benefit from additional probiotic + prebiotic supplementation.  

2. Ensure Adequate Vitamin D3 Through Food, Sunshine + Supplements

Research has shown that vitamin D can modulate both the innate and adaptive immune responses. Vitamin D has antiviral, antimicrobial and pro-hormone properties and has been shown to be protective against upper respiratory infections. Individuals with lower levels of vitamin D have been shown to have an increased susceptibility to infection. And this makes sense because vitamin D receptor (VDR) is present in the majority of immune cells. In addition to simply supporting the immune system, vitamin D may also help lower inflammation by lowering the expression of pro-inflammatory cytokines and increasing anti-inflammatory cytokines by macrophages. 

Researchers and clinicians identified that the Coronavirus is likely to enter the body through the ACE2 (angiotensin-converting enzyme 2) receptor. At the same time, the active form of vitamin D, calcitriol, has been shown in animal studies to increase protein levels of ACE2 and VDR. 

Dr. Rhonda Patrick recently shared a meta-analysis conducted in the BMJ in 2017 demonstrating that vitamin D supplementation cut the risk of respiratory tract infections by 50% in those that were deficient and 10% in people with adequate levels. Dr. Patrick noted in her post:

“While I want to be clear that I am not suggesting some magic cure for COVID-19 (please be aware), it is a fact that is beyond reproach that vitamin D status is an immune-impacting factor that strongly declines with age that is easily remidiable with supplementation. To highlight why this is an issue with older people, it’s generally thought that a 70-year-old is almost 75% less efficient at producing vitamin D from the same dose of sunlight as their former 20-year-old-selves.”   

Food sources of vitamin D include wild salmon and other fatty fish. This also includes wild salmon in BPA-free cans or pouches, which contains about 500 IUs of vitamin D. Beyond food sources, sunlight is the easiest for the body to absorb vitamin D. So try to spend sometime outside, if your climate allows.

You may also benefit from additional vitamin D supplementation of 1,000-5,000 IUs, depending on your current vitamin D levels. When it comes to vitamin D dosages, this is highly individualized. Certain factors such as being overweight, having darker skin, being an older adult, not going outdoors and having certain genetic mutations can all increase need. You want to get your vitamin D (25-OHD) levels checked by your doctor.

A general product that I recommend is Metagenics D3 5,000 + K because it is a high quality, third party tested brand of vitamin D3. For some, 5,000 IUs will be too much vitamin D. Note: for people on a blood thinning medication, this would not be a good choice. This is why it’s always best to check with your doctor or registered dietitian for what is best for you. 

3. Prioritize Vitamin C In Divided Doses

One of the benefits of consuming a variety of fruits and vegetables is that they are chock full of vitamin C, which is a potent antioxidant. Vitamin C, also known as ascorbic acid is a nutrient that is reported to also support both your innate and adaptive immune function. High doses have been reported to stimulate phagocytic T-lymphocyte and to protect lymphocytes from oxidative stress. The research on vitamin C is mixed but it does appear that vitamin C can aid in recovery time. A 2019 meta-analysis that reviewed 18 trials found vitamin C helped decrease the length of stay in the ICU. In 3 of those trials, vitamin C also helped to reduce the duration of mechanical ventilation. 

Foods that are rich in vitamin C include red and green bell peppers; kiwi; berries; citrus fruits like lemons, limes, grapefruit, and leafy greens.

You may benefit from additional vitamin C supplementation but aim for taking small, divided doses of about 500mg throughout the day. Because vitamin C is a water soluble vitamin, there is no risk of toxicity. The downside of taking too much at once is that you can only absorb so much in one sitting and a common side effect of higher vitamin C dosing is soft stools. If you are supplementing with vitamin C, pay attention to your bowels! 

As an added bonus, vitamin C may help curb the stress response because it supports your adrenal glands, which are responsible for the production of cortisol, your body’s primary stress hormone!

4. Incorporate Zinc 

Zinc is a mineral and a powerful antioxidant. Like vitamin D, deficiency of zinc is more common among eldery patients. Deficiency can be associated with decreases in immune cell development and innate immune cell function, in addition to decreases in adaptive immunity through T helper cells. While the research is clear that deficiencies can negatively impact the immune function, there is some controversy around whether zinc enhances immune function in human studies.

One randomized, double-blind trial of zinc supplementation among adults 55-87 years old found that supplementing with 45 mg zinc/day for one year slightly lowered the incidence of the common cold and fewer infections. Another randomized, double-blind placebo-controlled trial found that 30mg of zinc supplementation per day for 3 months enhanced T cell function. No matter what, you want to make sure that you are consuming adequate levels of zinc through food sources and you may want to consider additional supplementation. 

Foods rich in zinc include oysters, crab, lobster and meats like grass-fed beef and organic chicken. An amazing plant-based source can be found in pumpkin seeds. I highly recommend SuperSeedz that have different pumpkin seed flavors.

Note about supplementing: taking more than 100mg/day can increase risk of prostate cancer, copper deficiency, fevers, chills and headaches. Also, I often recommend zinc lozenges which have been shown to have higher absorption but in some cases, can cause nausea and vomiting, upset stomach and diarrhea.    

5. Eat Omega 3 Rich Fish 

Omega 3 polyunsaturated fatty acids are essential fatty acids, meaning the body cannot produce them itself. Eating high quality food sources of omega 3s and additional supplementation is necessary. These healthy fats are a primary building block of the immune system because they directly influence T cells and also play a powerful role in inhibiting the production of inflammatory mediators such as eicosanoids, cytokines (Interleukin-6, Interleukin-1beta, and TNF-alpha) and reactive oxygen species. EPA + DHA act as resolvins and protectins which help reduce neutrophil infiltration and the inflammatory response. 

The best way to get EPA + DHA is by eating 2-4 servings of omega 3 rich fish per week such as wild salmon, sardines, anchovies, herring, mussels. You can purchase these through online vendors like Butcherbox, Thrive Market or Vital Choice. You may also benefit from a fish oil supplement like Nordic Naturals. 

Additional plant-based sources of the precursor to EPA + DHA include ground flaxseeds, chia seeds, hemp seeds and walnuts. These are an easy pantry staple to keep stocked and in your diet daily. 

If you are taking warfarin or glucocorticoids consult your doctor before taking an omega 3 supplement. 

6. Add Ginger to Smoothies + Warm Beverages

Ginger root provides an incredible addition to the diet due to its anti-inflammatory and immune boosting benefits. A 2020 meta-analysis demonstrated that ginger supplementation had a statistically significant effect on lowering CRP, TNF alpha and Interleukin-6 (IL-6). There’s been a lot of discussion about the cytokine storm, which is why herbs like echinacea and elderberry are not being recommended for immune support against the Coronavirus. One of the key pieces to decreasing the cytokine storm is lowering IL-6, which ginger root and fish oil have been shown to do.

I recommend using ginger in its root form versus powdered because the root is more potent. But if you don’t have fresh ginger root and you can’t get to a store, it does not hurt to add ginger powder when cooking. Try adding to your smoothies or in my Cinnamon Lemon Ginger Tea recipe. 

7. Add Fresh Minced Garlic When Cooking 

Garlic has been used for centuries to help combat infectious disease. It contains compounds called alliin and allicin which have antimicrobial activity. There isn’t a lot of strong evidence on garlic’s impact but the small studies that have been conducted indicate garlic may stimulate the immune system and have antimicrobial effects, in addition to lowering inflammation, lowering cholesterol and blood pressure for individuals with mild hypertension.

Try adding 1-2 cloves of fresh minced garlic to salads and other dishes that you are preparing for a boost in anti-microbial and gut-friendly activity. 

Check-in with your doctor if you are taking warfarin or any other blood thinner, insulin or protease inhibitors to ensure garlic supplementation is a safe choice. 

8. Sip on Green Tea 

Active components of green tea include epigallocatechin-3-gallate (EGCG), theanine, and caffeine. Green tea and EGCG appear to effectively modulate several aspects of innate and adaptive immunity but this has been shown mainly in animal studies. Animal studies have shown that EGCG can inhibit cytokine production and T cell proliferation. Some of the associations between EGCG and immune health may be related to protecting against autoimmune diseases (the body attacking itself). 

While we still do not know enough about the research in humans, I recommend drinking 1-3 cups of organic green tea per day to increase intake of polyphenols which help support a healthy gut microbiome and may have additional benefits related to heart health and blood sugar levels.  

I am sending you my thoughts and prayers during this difficult time. Should you have any general questions related optimizing immune health or supplementation, please email me at [email protected] or follow along my Instagram and Facebook for updates on upcoming facebook lives and webinars. But please be mindful that, for as much as I want to be helpful, I cannot give individual nutrition advice over the internet.

This article was written for general educational purposes by a registered dietitian, not a doctor. Any questions that you have regarding your own health and supplements should be addressed with your own physician or other healthcare provider.  

Please continue to seek out reliable information and stay up to date through websites like the Centers for Disease Control and Prevention, the World Health Organization and your local public health department.