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Boost Your Immunity Starting Today

Your daily diet plays an important role in whether you’ll get sniffles, congestion, and more. Follow these strategies for better health—and breathing.

There’s a powerful army, our immune system, inside each one of us that battles unwelcome viruses and bacteria, as well as other things that can make us sick. It’s made up of natural chemicals, proteins, and cells, as well the gut and the mucous membranes in the nose and throat. Its one job is to keep us healthy.

The immune system is working constantly, much of the time without you even knowing it. A strong immune system is able to fight off viruses and infections so you don’t get sick. A weak immune system is one that’s unable to effectively defend the body against germs, which is why some people get sick more frequently—and stay sick longer.

To get a stronger immune system, follow these expert diet strategies:

EAT MORE COLORFUL FRUITS & VEGETABLES

The deeper the color of a fruit or vegetable, the higher its antioxidant content. Antioxidants are natural plant chemicals from which fruits and vegetables get their bright colors. Adding a variety of colorful fruits and veggies to your daily diet provides essential nutrients that can keep your immune system strong, reducing overall inflammation in the body—and in the lungs. “There are over 100,000 phytonutrients in plants,” says Tina Marinaccio, MS, RD, CPT, Healthy Living’s Integrative Culinary Registered Dietitian. “We need a variety of plants and phytonutrients in our diet. Instead of focusing on one food, commit to getting a variety of colors or phytonutrients in your diet every day.”

Flavonoids are the main category of phytonutrients found in all plants. These are some foods that can be particularly helpful for better breathing:

Apples are rich in quercetin (kwhere-SE-tin), a yellow-hued plant chemical. “Quercetin has been shown to decrease inflammatory histamine in the body,” explains Marinaccio. It’s histamine, a natural chemical produced by immune cells, that triggers allergic reactions and the contraction of the muscles in the lungs, causing wheezing. Quercetin also decreases viral growth and keeps lungs healthy. This makes it an important nutrient for those who typically suffer from seasonal allergies. (Quercetin has also been shown to help reduce the symptoms of COVID once someone gets sick with the virus.)

Blueberries contain anthocyanins (ann-though- SIGH-a-nins), which may help inhibit the release of natural inflammatory molecules, such as histamine, in the body. Blueberries are also high in fiber and vitamin C.

Red bell peppers contain carotenoids (ker- ahh-TEN-oids), as do other orange and red foods such as watermelon and carrots. These phytochemicals have been shown to help reduce overall inflammation in the body.

LIMIT PROCESSED SUGAR

Sweet treats—from donuts and cookies to pies and pastries— can reduce the effectiveness of your immune system. Eat too much processed sugar on a daily basis and your chances of getting congested or feeling sick increases. Your best bet: limit sweets to special occasions, and keep an eye out for sugars added to everyday foods, even seemingly healthy foods like sweetened yogurt, peanut butter, and ketchup.

By reading the nutrition panel, you’ll be able to gauge how much sugar you’re getting daily—and cut back accordingly.

ADD PROBIOTICS TO YOUR DIET

The gut, or microbiome as it’s sometimes referred to, plays an important role in how our immune system works. In fact, 70 percent of immune cells are found in the gut. It makes sense then that if the gut is healthy, the immune system is healthy and your respiratory health is good—something called the “gut-lung axis,” explains Marinaccio.

One thing critical to a healthy gut-lung axis is having enough good-for-you bacteria called probiotics in the gut. A good way to get these good bacteria into the gut is through fermented foods. “Fermented foods help build up the fortress of good bacteria in your gut,” explains Marinaccio. As with phytonutrients, the more variety of fermented foods you can get in your diet, the more diversity and balance of bacteria you’ll have in your microbiome.

Fermented or probiotic foods include tempeh, natto (a staple food in Japanese cuisine), kombucha (fermented green or black tea), miso, and kimchi (a fermented Korean side dish). Sauerkraut and pickles are also fermented but to be effective they need to be sold in the refrigerated section. (The ones found in the non-refrigerated aisles don’t contain healthy bacteria.) Cultured dairy, if you can eat dairy, is also considered a fermented food; this includes kefir (a thick yogurt-like drink) and yogurt.

So-called “prebiotic” foods are also important to include in your diet. These foods—like oats, asparagus, Jerusalem artichokes, leeks, onions, and legumes— contain fiber that provide food for healthy bacteria in the gut.

GET ENOUGH OF THE KEY NUTRIENTS

While all nutrients are important for a healthy, balanced body, these nutrients in particular are important:

Beta carotene helps nasal passages function properly so they can better trap and fight off germs. Beta carotene—found in green leafy vegetables as well as in yellow and orange fruits and veggies—is turned into vitamin A in the body.

Vitamin A is essential for the production and function of immune cells. It signals your body to create more infection- and germ-fighting white blood cells. This nutrient also helps maintain the body’s mucous membranes, including in the nose and the lungs. It’s these membranes that help trap bacteria and viruses before they can infect the body. Low levels of vitamin A have been associated with more frequent respiratory infections, while higher blood levels of vitamin A have been linked with better lung function.

Magnesium is a nutrient critical for lung function. It’s been shown to help improve breathing. Some researchers believe that inadequate amounts of magnesium in the body may cause a buildup of calcium in the muscles lining the airways of the lungs. This can cause the airways to constrict, making breathing more difficult. Foods high in magnesium include dark chocolate with at least 70 percent cocoa; avocados; nuts like cashews, Brazil nuts, and almonds; legumes like lentils, black beans, and garbanzo beans; and seeds like pumpkin, flax, and chia.

Omega-3 fatty acids are essential fatty acids found in cod liver oil and seeds like flax and chia seeds, as well as in oily fish like salmon, mackerel, and sardines. They are known anti- inflammatories and seem to help reduce the production of IgE, the antibodies churned out by the immune system that cause allergic reactions. Omega-3 essential fatty acids also help reduce the severity of cold and flu symptoms if you do get sick.

Potassium is a nutrient that helps the lungs to expand and contract. A deficiency may contribute to shortness of breath. In fact, one study from the University of Southern California found that children who don’t get enough potassium and magnesium in their diets have lower lung function (a measure of how well their lungs work). Good sources include avocados, dark leafy greens, and bananas.

Vitamin C is a powerful natural antihistamine, which means that it’s naturally able to reduce or block histamines, the compounds in the body that trigger allergy and asthma symptoms. It’s also an anti- inflammatory antioxidant that’s essential for immune health. It seems to help reduce inflammation in the body and particularly in the airways. Research shows that a deficiency in vitamin C results in greater susceptibility to sickness.

Your body can’t make vitamin C, why you have to get it from food. The best sources of vitamin C include citrus fruits, strawberries, acerola cherries, sweet yellow peppers, thyme (which has the greatest concentration of vitamin C of all culinary herbs), parsley, kale, kiwis, and broccoli.

Vitamin D helps the immune system produce something called antimicrobial peptides or AMPs. These are the body’s natural “antibiotics” that help kill viruses and bacteria and stop infections. Vitamin D is also important for the activation of T cells, important white blood cells that fight viruses and infections. It makes sense then that a deficiency in this vitamin is associated with an increased susceptibility to infection. University of Minnesota researchers found that people who had a deficiency in vitamin D were more likely to get seriously sick from COVID-19 than those who had normal levels of vitamin D in the blood.

The body can’t produce enough vitamin D, why we have to get it from from the sun’s ultraviolet light. (The skin absorbs this light, which is then converted into vitamin D in the body.) We can also get some D from our diet from foods like salmon, eggs, and fortified milk and juice. Supplementation may also be necessary if your levels are low; talk to your doctor to have your levels tested.

Vitamin E has anti- inflammatory and antioxidant properties like vitamin C. It also promotes the activity of T-cells, white blood cells involved in protecting us from viruses and other infections.

Some studies have shown that a type of vitamin E called gamma tocopherol may help reduce airway inflammation. Gamma tocopherol is found in foods like walnuts, pecans, and pistachios. For those who are sensitive to tree nuts, ground flaxseeds (which are better digested by the body than whole flaxseeds), sesame seeds, and pumpkin seeds are also good sources.

Zinc is a mineral found in meats, poultry, seafood like crab, eggs, whole grains, and dairy products and is important for the development and function of immune cells. This means that your body needs enough zinc to effectively fight off viruses like colds, RSV, and COVID. In fact, one study found that people with COVID who had low zinc blood levels had worse outcomes.