Research-Supported Immune Boosting Strategies for Fall and Winter

in Nutrition Wellness

Part 2: Proven Supplements to Support Your Immune System

Research-Supported Immune Boosting Strategies for Fall and Winter

Immune-enhancing supplements are not magic bullets, but many have solid scientific evidence backing their use. As part of a holistic immune health strategy, targeted, proven supplements can help you prevent, shorten and recover more quickly from viral illnesses like influenza and possibly COVID-19.

In part 1 of this immune health series, I talked about the role of vitamin D in optimizing immune function. I focused especially on its potential to reduce the incidence and severity of COVID-19 infections — a promise that is being increasingly studied, but that hasn’t necessarily made its way into mainstream medicine’s recommendations…yet!

Today I’d like to dig deeper into the trove of vitamins, herbs and other supplements known to improve immune function and help fight off the flu and other viruses. From familiar favorites like vitamin C to more surprising supports like the leaves of the olive tree, there are dozens of demonstrated natural immune enhancers which you can consider building into your seasonal wellness plan while working with a qualified professional.  

First, it’s vital for me to stress that supplements are just one small part of your ideal strategy to increase your resistance to infection. When I meet with my clients, we focus on immune health. This involves a comprehensive approach that builds on supporting optimal nutrition, healthy gut function, regular movement, quality sleep, stress management, and supportive practices like prayer or meditation. There is no one herb, formula or magic bullet that will give you iron-clad protection against illness, and each person is unique as to what may be best for their situation. However, there are SO many supportive nutrients and practices that can work together to help you build a more robust and resilient immune system. 

In this time where many are fearful and overwhelmed in the face of the pandemic, I want to share scientifically-backed information that can help you take positive action. Hope and empowerment are strong antidotes to fear and paralysis, and I believe both are powerful agents in their own right for building or maintaining optimal wellness. So let’s take a look!


Julie’s Favorite Immune Support Supplements

The list of evidence-based supplements for immunity is long, so I’d like to break my favorites down into seven categories and give brief info on each. 

If you’re a clinician or nutrition wonk, I offer more in-depth information and detailed references on nutrition, supplementation and immunity in this article I wrote for the Association of Gastrointestinal Motility Disorders (AGMD) this summer.

Key Vitamins & Minerals

  • Vitamin D. This powerful vitamin derived from sun exposure has been shown to improve immune function, prevent infection and reduce the severity of viral illnesses. In new studies conducted since spring 2020, it’s showing promise as both a preventive and treatment option for COVID-19 — an exciting and important development you can learn more about in part 1 of this series. I often recommend Hi-PO Emulsi D Liquid (Designs for Health) for those who need to supplement. (Be sure to get your levels checked annually to determine need for supplementation.)
  • Vitamin C. Vitamin C is found in citrus fruit and other fruits and vegetables, and is a key antioxidant that protects against cellular damage, infections and cancer. It’s been shown to help prevent cold and flu symptoms and reverse the course of these illnesses, and it’s increasingly being used in high-dose IV protocols to help address antibiotic-resistant infections. I usually recommend 2000-4000 mg/day using a buffered formula in divided doses, taken with food to prevent stomach upset.
  • Zinc. Research on zinc has found strong antiviral properties against many viruses. Zinc enhances the immune system while also reducing symptoms and spread of viruses. It has also been used in some protocols throughout the country to treat COVID-19. Note: while lower doses of zinc on a daily basis may be quite safe, if you are taking larger doses above 30mg/day for longer than several weeks, copper levels may be compromised and copper rich foods or supplementation may be needed. Over time, high dose zinc can depress the immune system. It is important to work with a practitioner trained in supplements.
  • Key minerals. The immune system relies on a number of key minerals such as magnesium, selenium, and chromium for healthy functions that include producing virus-fighting cells and antibodies and helping to regulate inflammation. Including a  mineral formula as part of your multivitamin-mineral or as a stand-alone can help ensure you’re not deficient and that you have these minerals in a healthy balance. 


Antioxidants are your body’s key defense against cellular and DNA damage from free radicals — molecules that wreak havoc by stealing electrons from others. When free radicals outnumber antioxidants, you can get an inflammatory condition called oxidative stress. Oxidative stress plays an important role in influenza and other viral illnesses and has been proposed to be critical in the lung and organ damage caused by severe COVID-19 illnesses. One way to bolster your immune system, lower inflammation and repair cellular damage is through eating antioxidant foods and supporting your body with nutraceuticals.

Glutathione is often called your “master antioxidant” and can be found in foods such as asparagus, walnuts, spinach, and avocados. Also, taking a glutathione supplement OR a supplement that supports glutathione levels such as NAC, n-acetyl-cysteine, which is a precursor, to support tissue levels of glutathione may be helpful. NAC is one of the major antioxidants in lung tissue. There is evidence that oxidative stress contributes to the pulmonary damage that may result from influenza. Studies have shown that supplements that boost glutathione have reduced the frequency and severity of influenza episodes. 

Vitamin C and E are both powerful antioxidants you can obtain through a healthy whole foods diet and supplementation if needed. They also support healthy glutathione levels. Three antioxidant support formulas I often recommend are NAC (Pure), Liposomal Glutathione (Pure or QuickSilver) and Antioxidant Formula (Pure). 


  • Elderberry. This gorgeous and delicious berry could win an award for my clients’ favorite formula to take (and mine!). Its power lies in its proven ability to lessen the severity of colds, flu and other respiratory illnesses. You can take 600–900 mg/day of an extract standardized to contain 22% polyphenols and 15% anthocyanins. It would be wise to discontinue during an active COVID infection. It has been highly debated that it may or may not stimulate a cytokine storm, an increased and harmful inflammatory response.
  • Olive Leaf Extract. Extract of olive leaf has demonstrated broad spectrum antimicrobial and antiviral properties, including against influenza. A product I use often during flu season is Olivirex (Bio-Botanical Research).
  • Green Tea/EGCG. There is accumulating evidence of immune benefits from consuming green tea or its active ingredient EGCG. The anti-inflammatory and antioxidant effects of EGCG are thought to be one of the main reasons for its role in disease prevention. A double-blind trial used the combination of green tea catechins and theanine (a compound present in green and black tea) and found a decrease in the incidence of influenza in healthcare workers.


Probiotics support your immune system by helping to populate more healthy bacteria in your intestines. They also help your mucosal lining secrete protective immunoglobulin, which is foundational to a healthy gut lining and barrier protection, helps prevent overgrowth of bad bacteria, and optimizes your immune system. A healthy balanced gut and strong barrier lining will help reduce inflammation as well. There are quite a few quality products I recommend, but, by far, the most effective in my practice has been Megasporebiotic (Microbiome Labs) and another new favorite is Ther-biotic Synbiotic (Klaire labs).


Beta-glucans are another place where you can get powerful immune-supportive properties from something delicious: specific mushrooms and the cell wall of oats! Beta-glucans that boost your defenses against both cancer and infectious diseases are found in the highest concentrations in the more exotic reishi, shiitake, and maitake mushroom varieties. You can also get a fair amount from oatmeal, barley and seaweed. For those of you who shudder at the thought of more oats, or mushrooms or mushroom tea, supplements are a great choice. Two good options are Beta 1,3/1,6- D–Glucan (NOW) and ImmunotiX 250 (Xymogen).


Immunoglobulins are one of the top supporters for immune and gut healing that I use in practice.  They help the intestinal immune system by binding a broad range of microbes and toxins within the gut and strengthen gut barrier function. Immunoglobulins have been shown to bind microbes and toxins in the GI tract and eliminate them before the immune system is activated. As these unwanted triggers are removed, it resets healthy immune tolerance and builds a stronger gut lining barrier to help protect you.  Immunoglobulins, as compared to colostrum, which contains dairy, are dairy free and lactose free making them ideal for those who are sensitive. Top products that I highly recommend:  SBI Protect (Orthomolecular), MEGAIgG2000 (Microbiome Labs), and MegaMucosa (Microbiome Labs).

Immune Support Formulas

Many reputable manufacturers offer formulas with ingredient combinations that work synergistically to support the immune system. Three great options I use in my practice are OliveDefense (Xymogen), Immun-Zyme (Apex), and Viracid (Orthomolecular). If your head is spinning from all of the info above and you’re looking for a single, balanced supplement, one of these may be right for you. It’s nice to have one of these on hand to take at the first sign if you feel you have a cold or the flu coming on.

I’ve shared a lot of information with you and my intention is not to overwhelm you, but to help you take steps to be informed and support your health in ways that are right for you. This is the perfect time to commit to focusing on our health and resiliency. 

In combination with a whole, plant-based, and varied diet; a healthy gut; and a supportive lifestyle, one or more of the above immune supports may help offer protection against COVID and this winter’s flu season. Regardless, the evidence is strong that it will increase your resistance to many diseases, both infectious and chronic, and, in my experience, offer you greater energy, vitality, and wellness.


If you’d like a short handout of my top immune support supplement recommendations, here is everything in one simple chart.


Download Julie’s Favorite Immune Support Supplements


Next up in my immune health series: HCL, PPIs and immune health. Stay tuned!

If you are looking for guidance on how to support your immunity through a personalized program that improves gut health and lowers inflammation and autoimmunity, consider connecting with me on a free 15-minute consultation.

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