Get full access to Outside Learn, our online education hub featuring in-depth nutrition, fitness and adventure courses, and more than 2,000 instructional videos when you sign up for Outside+..
You’ll likely always remember 2020 as the year the COVID-19 coronavirus pandemic led to a societal focus on external hygiene—including social distancing and frequent hand washing—to help prevent the spread of the illness. But have you paid as much attention to internal hygiene, practices that help optimize your immune system to ward off disease on its own?
It’s true that COVID-19 is a new virus that no one, up until recently, had been exposed to. However, we have to face the fact that we can’t live in a world free of cold and flu viruses, other foreign invaders, toxins, and stressors. No matter what we want to defend ourselves against, building up our immunity is the key to fighting off many different challenges.
Naturopathic physicians and other holistic-oriented practitioners focus on back-to-basics approaches—simple things that can make a big difference—to increase resistance. The practices that follow aren’t complicated: They promote health, which in turn supports the body’s natural ability to heal and protect itself.
1. Load up on vegetables
The more vegetables—and more varieties of vegetables—you eat, the better it is for your immune system and your health in general. Polyphenols, naturally occurring compounds in vegetables and fruits, help support beneficial gut bacteria while inhibiting harmful bacteria. This sets up an internal environment that helps our immune system function more efficiently. Other veggie nutrients, such as beta-carotene and vitamin C, help improve our immune defenses in other ways. For example, flavonoids, colorful polyphenols found in vegetables, fruits, and herbs, upregulate the body’s antiviral defenses while also downregulating excessive inflammation and immune overactivity, says Lise Alschuler, ND, of the Center for Integrative Medicine at the University of Arizona.
As a key strategy to help our immune defenses, we should shoot for eating 7–10 servings of vegetables, fruits, and herbs per day. According to researcher and educator Peter D’Adamo, ND, vegetables such as shallots, garlic, onions, and leeks deserve special mention: they contain substances called lectins that almost act as targeted antibodies against viral infections.
2. Avoid eating sugary foods
Consuming sugar suppresses the immune system by destroying the germ-killing ability of white blood cells for up to five hours after ingestion. It also interferes with the transport of vitamin C, one of the most important nutrients for healthy immune function. Plus, sugar is a source of empty calories—it doesn’t provide any nutrients to help the body fight off illness.
3. Stay hydrated
Drinking enough water is just as important for immunity as getting enough sleep. Water is needed to keep lymph fluid, a key component of healthy immune function, flowing smoothly.
Related: 31-Day Immune Health Challenge
The mucous membranes that line our nasal passages, lungs, and throat, which are on the front lines of the body’s defenses, cannot do their job well when a person is dehydrated. Water is also needed to allow the kidneys to flush out toxins and the digestive tract to remove waste from the body. So, drink more water!
4. Get some sleep
Lack of sleep depresses immunity by preventing the body from producing more cytokines to fight infection. Sleep deprivation can make you more susceptible to disease—including new and advanced respiratory diseases—and also increase the time it takes to recover from illness.
Adequate sleep—generally considered to be between seven and nine hours a night—plays an integral role in immune function because it positively impacts T cell function (an important component of immune response). As a key strategy to boost immunity, make it a priority to get regular, sufficient sleep.
5. Move your body
Moderate physical activity—even something as simple as taking a walk—boosts health and immunity in numerous ways. It improves the flow of lymph in our lymphatic system, which is the circulatory system of our immunity. Proper lymph flow transports immune cells around the body, where they patrol for foreign invaders; then, immune cells come together in hubs of immune activity called lymph nodes to fight infection. If the flow of lymph becomes impaired from lack of movement, this key part of our immune surveillance and defenses can become compromised.
6. Reduce stress
When we are stressed, our immune system’s ability to fight off foreign invaders is impaired, making us more susceptible to infections and illness. That’s why it’s imperative that we find ways to lessen our stress load. Whatever engages us fully and takes us out of our head for a while counts as relaxation. For some, that might be exercise. For others, that could be meditation, reading, listening to music, talking to friends, engaging in an absorbing hobby, cooking, walking, or doing yoga or tai chi. Whatever works for you should be an important part of your immune-boosting program.
7. Harness the healing power of nature
There is a strong connection between exposure to nature and immunological health, according to Kurt Beil, ND, LAc, MPH, vice president of the New York Association of Naturopathic Physicians. Being in nature promotes the same stress-reducing, health-enhancing effect as meditating, says Beil. His advice is to get outside, away from technology and the news, and walk in a park, nature preserve, or around the block. Or forest bathe—go into the forest and be still—if you can. There are phytoncides, germ-repelling and immune-boosting chemicals, that come from natural substances such as evergreen trees. If you’re stuck inside, bring nature indoors by having plants as well as pictures, calendars, and screen savers that have nature scenes in your home. These reminders of nature also offer positive health effects, says Beil.
Fortify Your Body with Supportive Supplements
No matter how healthy our diets are, many of us still have trouble getting adequate—let alone optimal—amounts of the nutrients necessary to build and support healthy immune systems. Supplements can help provide that extra boost.
For additional support, consider taking the following nutrients, either individually or in combination formulas.
Vitamin D: This fat-soluble nutrient plays a powerful role in immune health. It is a key factor linking innate and adaptive immunity; it enhances the pathogen-fighting effects of white blood cells; and it decreases inflammation, which helps promote appropriate immune response. Low vitamin D levels are associated with an increased risk of upper respiratory tract infections, including influenza.
According to a 2019 review of randomized control studies of 11,321 people, supplementing with vitamin D significantly decreases the risk of respiratory infections in people deficient in this vitamin, and even lowers infection risk in those with adequate vitamin D levels.
The body makes vitamin D when we are exposed to UV rays from sunlight. If you don’t get much exposure to the sun—or if you want extra assurance—consider supplements of vitamin D3. A dosage between 1,000 IU and 4,000 IU daily is sufficient for most people. But individuals with serious deficiencies may need more.
Zinc: This trace mineral is needed for immune cell development and communication. A deficiency in this nutrient affects your immune system’s ability to function properly, resulting in an increased risk of infection and disease.
Oral zinc supplementation reduces the incidence rate of acute respiratory infections by 35 percent, shortens the duration of flu-like symptoms by approximately two days, and improves the rate of recovery.
Related: 7 Benefits of Zinc
Foods high in zinc include lamb, beef, dark-meat chicken, pork, nuts, seeds such as pumpkin and hemp seeds, and mushrooms. Typical supplemental dosages range from 15–50 mg daily.
Vitamin C: A powerful antioxidant and cofactor for enzymatic processes that are crucial for healthy immunity, vitamin C is short-lived in the body, and prolonged infection or stress depletes it faster.
Supplementing with vitamin C has been shown to reduce the duration and severity of upper respiratory infections, including the common cold. A large review of 29 studies of more than 11,000 people demonstrated that regularly supplementing with vitamin C at an average dose of 1,000–2,000 mg per day reduces the duration of colds by 8 percent in adults, by 14 percent in children, and by up to 50 percent in individuals under high physical stress, including soldiers and marathon runners. Additionally, high-dose intravenous vitamin C treatment has been shown to significantly improve symptoms in people with severe infection, including sepsis and acute respiratory distress syndrome resulting from viral infections.
Foods rich in vitamin C include broccoli, cauliflower, kiwi, lemons, limes, orange juice, kale, papaya, pepper (red, green, or yellow), sweet potato, strawberries, and tomatoes. Many people take supplements of 500–2,000 mg per day, often in divided doses.
Aloe Juice: There’s a whole other side to aloe you may not know about. For example, did you know aloe juice is a potent immune booster, among other things? A clinical study on Lily of the Desert products with Aloesorb showed a 16 percent increase in white blood cell counts over a placebo group. Increasing the amount of white blood cells helps to further support a healthy immune system. Follow label instructions for dosage.
Combination Formulas: These generally contain some or all of the above nutrients plus herbs such as olive leaf extract, elderberry, echinacea, and medicinal mushrooms. See product examples to the right.
Note: Those with autoimmune conditions or digestive disorders may experience uncomfortable symptoms from multi-herb blends. If you have this problem, try a nutrient-based product such as Carlson ACES + Zn.
Did Industrial Food Set Us Up for COVID-19?
The 2020 coronavirus pandemic should bring global attention to the grave risks inherent in our modern food system, says Kristin Lawless, author of Formerly Known as Food: How the Industrial Food System is Changing Our Minds, Bodies, and Culture. First, our industrial food system is decimating the environment. Second, our nutrient-depleted and chemically saturated processed-food supply is changing our bodies from the inside out, Lawless wrote in an April 2020 article for the Organic Consumers Association.
Industrial farming has depleted our soil of nutrients. Without healthy soil, we can’t have nutritious food to support healthy immune systems. There also is emerging research that exposure to environmental chemicals such as pesticides, BPA, and dioxins—which are used in the growing of food ingredients and the packaging of food products—impair immune function and leave people more vulnerable to infectious diseases.
People who suffer from a chronic disease such as diabetes, cardiovascular disease, stroke, kidney disease, and various cancers, are particularly at risk. Preliminary findings show that metabolic dysfunction, which occurs with any of these diseases, can cause devastating complications from COVID-19. According to Lawless, metabolic dysfunction has one primary source: our highly processed, sugar-laden, nutrient-poor food supply.