Supporting your immune system is likely top of mind these days. While there are a number of ways to keep your body healthy, as an integrative doctor, I know the gut is not only the foundation upon which to build your health. It is also the gateway to your immunity.

Disturbances in the delicate balance of the gut ecosystem, such as dysbiosis (an imbalance in bad bacteria versus good), can create challenges for the immune system. That’s why I believe the key to strengthening our immune system is to strengthen the gut lining and improve the health of the gut microbiome.

One way I do this is by nourishing the body with strategic nutrients. It may come as a surprise that some of the nutrients I use to support a strong immune system aren’t commonly associated with immunity. Yet, by working on improving the health of the digestive system, these nutrients help fortify the immune system so it can ward off invaders efficiently:

1. Probiotics

Part of building a strong gut lining involves having the right type of bacteria present that can support it. We know there is some sort of cross-talk between the good gut bugs (probiotic bacteria) and our immune cells that help promote tolerance. Probiotics basically help keep the immune system in check, so it doesn’t overact.

In addition, bacteria that we call butyrogenic are also important as they feed off short-chain fatty acids produced by other important gut bugs. The right type of probiotic can support these bacteria while keeping your immune system in shape.

2. Prebiotics

This is indigestible fibre that becomes food for the good gut bugs.

Examples of prebiotic-rich foods include chicory root, Jerusalem artichoke, and dandelion greens.

The right prebiotics can help support the production of butyrate, which is so essential for the health of the colon cells. Butyrate can single-handedly turn off long-standing, uncontrolled inflammation in the body.

However not all prebiotic-consuming bacteria produce butyrate. Bacteria like Akkermansia municiphila that are essential for keeping the gut lining healthy, live in a synergistic relationship with the cells that line the gut border. They are very important for overall immune health.

3. Zinc

Zinc is an essential mineral needed for a bunch of important processes in the body, including the creation of antibody molecules, which are one of the important ways the body defends itself against infection.

Zinc comes in many forms – Zinc gluconate, Zinc picolinate, Zinc carnosine, among others. Zinc gluconate has the most studies showing its ability to shorten the duration of the common cold, while Zinc carnosine can help protect and support the gut lining.

4. Quercetin

Quercetin is a key gut health nutrient that serves several functions, including an ability to support good gut bugs as a prebiotic.

It also augments the effects of Vitamin C, synergistically helping to prevent the over-activation of mast cells, which secrete histamine when the body is inflamed.

Not to mention, quercetin acts as a zinc shuttle, getting natural antiviral zinc into cells where it can help mitigate viral replication.

5. Mushrooms

Certain types of mushrooms have key nutrients known as 3,6 beta-glucans that may offer an immune-modulatory effect.

Mushrooms help improve natural killer cell function, which is essential for fighting viruses.

I usually add a desiccated mushroom powder that includes reishi, cordyceps, shiitake, and maitake to my morning smoothie. It’s a great way to make sure I’m supporting gut and immune health simultaneously.

6. Vitamin D

The sunshine vitamin is probably one of the most commonly deficient vitamins I encounter in blood tests on my patients. We simply don’t get enough sun, or foods rich in vitamin D. These foods include salmon, cod liver oil, and matsutake mushrooms, among others.

But it’s perhaps most important to get vitamin D through safe sun exposure.

Why is it so crucial? Vitamin D regulates over 200 genes and plays a critical role in supporting healthy gut permeability, as well as a responsive, well-coordinated immune system. I typically take 2,000 IU through vitamin D supplements in the summer months and increase it to 5,000 IU daily during cold and flu season.

7. Epigallocatechin gallate

Epi- what? OK, Epigallocatechin is just a fancy name for the most powerful antioxidant found in green tea. I drink it in a matcha tea or latte prepared at home without sugar (which is an immunosuppressant).

Organic matcha, which is a powder made from ground-up green tea leaves, is a rich source for this antioxidant, making it a great way to get an immune-supportive nutrient while enjoying the flavour and aroma of matcha.

This bioflavonoid supports a healthy gut microbiome, liver detoxification, and can reduce inflammation. Like quercetin, it may also act as a shuttle to help move zinc into cells.


I’ve used these specific immune-supportive nutrients for years, and they work for me and my patients – but only when they’re combined with a healthy diet and lifestyle, plus at least six to seven hours of sleep per night.

Look, it’s inevitable that at some point you’ll be on antibiotics, stressed, eating the wrong foods—all things that can challenge your gut health, leading to an immune breakdown.

But you can always turn things around.

The good news is with these nutrients, a gut-healing diet, and a balanced life, you can navigate any pandemic, cold, or flu season yet to come.