11 Best Foods for Your Immune System
Updated: May 12, 2023
Recent science says nutrition plays the most significant role in maintaining strong immune function. Especially when virus season is high, immunology doctors recommend these immune-boosting foods.
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Gearing up your system to fight illness
A healthy immune system is always on the job, protecting your body against viruses, infections, and illnesses. But for this complex network to function round-the-clock, your cells need to be well-fed with immune-boosting foods. Research published in late 2021 in Frontiers in Physiology suggested that above all other lifestyle factors, nutrition plays the most significant role in maintaining great immune function—a relationship doctors saw in action during the pandemic. One study found that among patients hospitalized with Covid-19, 82.2% had a vitamin D deficiency. Other research has shown that deficiencies in nutrients like vitamin C, vitamin B12, selenium, iron, and omega-3 were also common among Covid-19 patients.
Roger E. Adams, PhD, a dietitian from Katy, TX, suggests one way to set your body up for success is to load your diet with variety. “Fruits and veggies provide plenty of antioxidants, water, fiber, and other nutrients to help you get off to a promising start,” Dr. Adams says. “It’s important to have balance, however, since no single food, nutrient, substance, or activity will boost this system alone.”
Dr. Adams and other nutrition specialists say a diet rich in colors is one place to start. Here are some nutrient-packed options to keep your immune system in fighting form.
Garlic
Get the breath mints ready. Garlic has been used for centuries to support the immune system and provide protection against a range of health conditions, including heart disease and Alzheimer’s disease. “The sulfuric compounds that garlic contains are most potent when raw, since heat inactivates sulfur enzymes,” says Frances Largeman-Roth, RDN, dietitian and author of Eating in Color. “To enjoy raw garlic, use it in pesto and also in chimichurri, which also contains shallots, chilies, vinegar, cilantro, parsley, oregano, and olive oil.”
Garlic happens to be the first ingredient listed in this flavor-packed chimichurri recipe from our sibling site, Taste of Home.
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Citrus fruit
While repeated research has debunked claims that vitamin C will totally prevent colds and flus, studies suggest that it may help you bounce back faster and experience milder symptoms.
“Citrus fruits, like oranges, lemons, grapefruit, and limes are all rich sources of vitamin C, which may help shorten the length of your cold or flu by about a day,” says Largeman-Roth. “Oranges and grapefruit can be eaten as snacks, of course, added to smoothies and salad dressings, squeezed into regular or sparkling water, and also used to make homemade ice pops.”
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Bell pepper
Bell peppers contain more vitamin C than citrus fruits (almost twice your daily recommended amount, according to the US Food & Drug Administration). Red bell peppers pack more of a nutritional punch than green, yellow, and orange bell peppers, though they are all considered to be good choices for a healthy diet. “Crunchy bell pepper slices make a great addition to a crudité platter and are also delicious sliced thinly in sandwiches, salads, and wraps,” suggests Largeman-Roth. “You can also add them to pasta dishes and stir-fries.”
The next time you’re fighting a cold, consider adding a bell pepper or two to your meal to give your body an extra boost. (It still counts if it’s on pizza!)
Broccoli
Whether you love it or hate it, broccoli is quite the superhero when it comes to boosting your immune system. “We often think of broccoli for its cancer-fighting properties, but it’s also an immune-booster thanks to its high content of sulfuric compounds called glucosinolates,” says Largeman-Roth. “One cup of cooked broccoli has 74 milligrams of vitamin C, which is nearly as much as an orange.”
She recommends eating broccoli steamed or roasted, adding stalks to salads, or dipping it in homemade yogurt-based dips. If you’re going to cook it, consider looking in the freezer aisle, as it’s one of those vegetables that are more nutritious in its frozen form.
Another green light for this green classic? Broccoli is also one of the best natural laxatives.
Spinach
Spinach is packed with vitamins, including vitamin C and antioxidants, which make it a powerhouse of immune-boosting goodness. It’s also rich in iron, with six milligrams in one cup, according to the National Library of Medicine. “Iron is necessary for the immune system to function properly,” Largeman-Roth says.
She recommends adding baby spinach to your salads and doing a sauté of spinach leaves with garlic and pine nuts. Her clever pro tip: “Just be sure to enjoy spinach with a food high in vitamin C to absorb all of the iron.”
Almonds
The almond is one of the healthiest nuts you can eat. Almonds are packed with vitamins and minerals, including vitamin E, which is vital to the immune system.
Another key nutrient found in almonds is zinc, which has immune system-boosting benefits and can fight off infections—including those that involve broken skin. “Zinc is involved with all cells, including inflammatory cells and skin cells, and protein and collagen synthesis,” Largeman-Roth says. “Without enough zinc in the body, wounds may take longer to heal.”
She recommends enjoying almonds as a snack, or chopping them up and using them to top your yogurt, oatmeal, cereal, and muffins.
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Tea
Sipping brewed tea is one of the oldest and surest ways to give your body the tools it needs to build a strong immune system. Each type of tea—green, black, white, or oolong—comes with its own list of health benefits. “Darker teas like black and green teas are rich in antioxidants that can help scavenge free radicals in our body,” Dr. Adams says. “Free radicals can cause early cell death and also alter cellular functioning, so keeping a good supply of antioxidants are always a good idea.” He recommends incorporating some freshly brewed black or green tea throughout the day into your normal beverage rotation.
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Chicken soup
It isn’t a myth—chicken soup is great for immunity, especially if it’s got a hearty amount of chicken. “The protein boost will ensure you have the building blocks necessary to keep your immune system in shape and the broth adds a boost of hydration,” Dr. Adams explains. “Chicken soup, and other vegetable-based broth soups, are high in vitamins A and C, magnesium, phosphorus, and antioxidants.”
As an easy way to boost your body’s defenses against illness, he recommends incorporating a cup of broth-based soup with protein and veggies several days per week.
Elderberry
If you’re suffering from a cold or the flu, or simply hoping to prevent illness, reach for elderberry extract. Research published in the Journal of Function Foods found that elderberry may minimize flu symptoms. Packed with antioxidants and antiviral properties, it can impact flu signs if it’s taken in the first 24 hours of onset. Elderberry can be taken as a syrup, tincture, or lozenge, and has been used for centuries to treat ailments and wounds.
Yogurt
Consider yogurt a friend to the immune system. Its benefits come mainly from probiotics (friendly bacteria that have been found to improve gut health) which may improve immune health, according to research published in the journal Annals of Nutrition and Metabolism. Adds Susan B. Dopart, MS, RDN, CDCES, a registered dietitian and the author of A Recipe for Life by the Doctor’s Dietitian: “Gut health is the key to a healthy immune system,” adding, “Probiotics are extremely important to gut health.”
When you choose your yogurt, make sure the label includes the phrase, Contains live and active cultures and lists a minimal amount of added sugar to score maximum benefits.
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Sweet potato
Their sweet flavor might convince you that they’re not all that healthy, but sweet potatoes offer quite a lot of immune system benefits. “Due to their rich colors, sweet potatoes are rich in vitamin A and beta carotene, both powerful antioxidants,” says Adams. Sweet potatoes can be baked or roasted, and they bring delicious flavor to salads.
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Additional writing and reporting by Jen Babakhan.
- Roger E. Adams, PhD, nutritionist and dietitian in Katy, Texas
- The Cochrane Database of Systematic Reviews: "Vitamin C for Preventing and Treating the Common Cold"
- Frances Largeman-Roth, RDN, dietitian and author of Eating in Color
- USDA FoodData Central: "Peppers"
- InformedHealth: "How Can I Get Enough Iron?"
- Journal of Functional Foods: "Anti-influenza activity of elderberry (Sambucus nigra)"
- Annals of Nutrition and Metabolism: "Beneficial Effects of Probiotic Consumption on the Immune System"
- Susan B. Dopart, MS, RD, CDE, author of A Recipe for Life by the Doctor's Dietitian
