At the time of writing this, COVID-19 has swept the globe, infecting over 3.25 million people worldwide and killing over 231,000. While we’ve done plenty to mitigate our risk of infection—from practicing social distancing to perfecting personal hygiene to focusing on immune health—one factor may be overlooked by many: Bolstering the health of our gut microbiome to avoid an inflammatory storm.

Consider this: Some people infected with COVID-19 show no signs and some have only minor flu-like symptoms. Others who contract the novel coronavirus—people with conditions such as diabetes, hypertension, kidney disease or those at an advanced age—can have an acute systemic inflammatory response that may result in death. And others still, including people between the ages of 20 and 60 who become infected but have no known underlying medical conditions, “develop serious illness requiring intensive care treatment,” the Lippincott Nursing Center reports. What dictates the severity of responses?

One theory that’s currently being investigated is the concept of an inflammatory or cytokine storm—in short, an excessive immune response to potential danger. As NPR reports, “Now doctors and researchers are increasingly convinced that, in some cases at least, the cause is the body’s own immune system overreacting to the virus. The problem, known broadly as a ‘cytokine storm,’ can happen when the immune system triggers a runaway response that causes more damage to its own cells than to the invader it’s trying to fight.” And this surge in an immune response can lead to the fatal shut down of multiple organs.

As you may know, your immune system is your body’s natural defense system against infection and illness, and includes two main parts that work in concert with each other—your innate immune system (which you are born with) and your adaptive immune system (which, as John Hopkins Medicine puts it, “you develop when your body is exposed to microbes or chemicals released by microbes”). Other than your nervous system, your immune system is the most intricate network in your body, working tirelessly at patrolling for invaders. But when it goes into overdrive in an attempt to keep you healthy, it can get stuck doing so—failing to shut off and “sending off the alarm long after it’s needed,” says Morning Edition.

This occurs in your innate immune system, which holds a multi-protein complex, known as the NLRP3 inflammasome, that instigates an inflammatory form of cell death and triggers the release of proinflammatory cytokines. While researchers are still learning more about this phenomenon, it’s believed that this happens when the immune system encounters a new pathogenic trespasser, which then causes cytokines to surge—and we all know now that COVID-19 is heretofore unknown. (Indeed, cytokine storms are thought to explain the devastating effects of the 1918 Spanish flu pandemic.)

So how can you do all that you can to help your body have a proper immune response to infections, rather than an extreme, possibly deleterious reaction? Part of this may rest in the health of your gut microbiome.

Your gut microbiome—the community of bacteria that lives in your gut—plays a vital role in a number of functions, including your mood, the amount of energy you derive from your diet and, yes, your immune system. At the same time, your immune system and the gut work in a symbiotic relationship, moderating one another and working to support each other—an interaction that’s underscored by the fact that, according to Cellular and Molecular Immunology, 70% to 80% of the body’s immune cells are contained in the gut.

To build and maintain this healthy crosstalk, it’s important to first think of your GI tract as a system as intricate as a rainforest, with a multifaceted system of life. It’s been adapted to accommodate a wide range of microbes, and to upset its delicate balance may lead to a host of health problems, including an exaggerated response to an invader.

This internal ecological system is influenced by the way you live your life and the decisions you make on a daily basis. What you eat, how often you move, the quality of your sleep, your external environment, your emotions and moods, the medications you take, your social life—all can contribute to your gut health. While several factors can impact your gut health and influence a decreased or dysregulated immune system—including nutrient deficiency (such as a zinc deficiency, as seen in those with pyrrole disorder, as well as those who eat diets low in antioxidant-rich fruits and vegetables), stress, insulin resistance, food allergies and intolerances (which can create systemic inflammatory effects, impact the intestines, and contribute to irritable bowel syndrome), over-the-counter medications such as antacids and NSAIDs, toxin exposure (to, say, heavy metals, pesticides and prescription medication) and genetics—you can take your gut health into your own hands.

Given that it’s your gut we’re talking about, it makes sense that its health is to a large part dependent on your diet. In fact, the single most important factor for a strong microbiome is what you eat. A microbiome in equilibrium is full of bacteria that produce specific short-chain fatty acids that positively affect wellness. These include acetate, propionate and, especially, butyrate—highly biologically active compounds that promote gut health, blood sugar regulation, optimal blood fat levels, appetite control and immunity. This friendly flora needs nourishment, which can then have a huge impact in shifting the inflammatory cascade. In addition to a healthy diet, rich in organic food, here are a few foods to nurture it right:

Green Tea

EGCG—the chief catechin in green tea—has been linked to a variety of health benefits. Functioning as a powerful antioxidant, it not only protects cells from oxidative damage but also encourages gut health. A 2019 review of studies and trials published by Nutrients found that green tea consumption resulted in the reduction of Firmicutes (an unfriendly bacteria) and improved levels of Bacteroidetes (a friendly bacteria)—changes, the authors say, that could help prevent gut dysbiosis (microbial imbalance). Green tea can also inhibit NLRP3 inflammasome activity and increase Nrf2 (which decreases inflammation). What’s more, a randomized control study out of Japan on 200 healthcare workers showed the incidence of influenza was lower in the group that took 378mg of green tea catechins and 210mg of the amino acid L-theanine per day. The amount of EGCG in each cup of tea depends on the quality of the tea. Some resources suggest 50mg to 100 mg, and others as high as 180 mg.

Pomegranate

Also rich in antioxidants, pomegranate can have a positive impact on gut flora by acting as a prebiotic—compounds that help “good” bacteria flourish in the intestines. A 2015 study published in Anaerobe reveals that pomegranate extract and pomegranate juice increased the mean counts of Bifidobacterium and Lactobacillus (friendly bacteria) and inhibited unfriendly bacteria such as the B. fragilis group. Another study in Anaerobe found that pomegranate stimulates the growth of a bacteria known as Akkermanisa Muciniphila—an intestinal bacteria superstar that supports microbiome health and offers protection from disease.

To boost your own intestinal health, you can drink eight ounces of pomegranate juice daily or take it as a supplement, 400mg to 800 mg a day. Note: Check with your doctor before making pomegranate a regular part of your diet. Pomegranate can lower blood pressure so if you are on a bp-lowering medication, your blood pressure could become too low if you drink a lot of pomegranate juice. Pomegranate may also interfere with some medications.

Broccoli Sprouts

Broccoli sprouts—small, immature seedlings of the broccoli you typically eat—contain sulforaphane, a sulfur-rich compound, found in cruciferous vegetables, that has been shown to have immune enhancing benefits, and inhibit multiple inflammasomes that cause cytokine storms (one of which is the aforementioned multi-protein complex known as the NLRP3 inflammasome). Use them in lieu of lettuce or bean sprouts in a sandwich, on top of your avocado toast, in a salad, or as a soup topper. They have a spicy, almost radish-like, flavor so don’t put them in your smoothie. And they are very easy to grow on a counter at home.

Turmeric

One of the boons of turmeric—or, more specifically, the phytochemical curcumin that’s found in it—is that it operates as an anti-inflammatory. Used in Ayurvedic medicine as a digestive healing agent, it began being recommended as treatment for acid reflux, flatulence and functional dyspepsia by the World Health Organization in 1999. What’s more, it works synergistically with ECGG, vitamin C, and quercetin to stimulate the production of immune-boosting enzymes. To have more turmeric in your diet, enjoy eating curries, add it to smoothies, or make “golden milk.”

Walnuts

Eating a handful of walnuts per day—roughly 16 walnut halves—boosts the bacteria species that generates butyrate, thus changing the microbiome for the better. Other nuts that encourage a healthy microbiome include pecans, almonds, cashews, pistachios and hazelnuts.

Foods Rich in Quercetin

Quercetin is one of the most abundant antioxidants in many grains, fruits and vegetables (it also gives some of these their pigment) and naturally supports your ability to ward off free radical damage. It also increases gut microbial diversity, which protects your gut and immune health. While quercetin supplements are available, you can up your intake of it through the consumption of foods with a high quercetin content, such as apples, onions, grapes, broccoli, berries, cherries, citrus fruits and capers. Other options include tea (black and green), red wine, spinach, kale, buckwheat and olive oil.

Prebiotic and Probiotic Foods

Prebiotics—a type of fiber the human body cannot digest—work as food for probiotics, microorganisms that help the body cultivate and maintain a healthy colony of bacteria. Prebiotics are present in many high-fiber foods, including Jerusalem artichokes, garlic, onions, leeks, barley, banana and flaxseeds. Foods rich in probiotics, meanwhile, include yogurt, kefir, miso, tempeh, Kombucha and fermented foods such as sauerkraut and kimchee.

Eat your way towards an effectual immune response? Absolutely.

Click here to buy Dr. Laurie Steelsmith’s books, Natural Choices for Women’s Health, Great Sex, Naturally and Growing Younger Every Day: The Three Essential Steps for Creating Youthful Hormone Balance at Any Age.