23 Immune-Boosting Foods: Fruits, Veggies, Proteins & More
You chow down on orange slices or sip ginger tea when you feel a cold coming on—but incorporating immune-supporting foods in your daily diet may have been more of a bonus than a priority. But now, amid a pandemic and pending cold and flu season, a top question on your mind may be: What can I eat to boost my immune system?
While there's no real way to "boost" the immune system, there are definitely ways to support immune function—and yes, a nutrient-rich diet is one of them.
"First of all 60 to 80% of our immune system is in our gut and is known as the gut-associated lymphoid tissue (GALT)," registered dietitian Ella Davar, R.D., CDN, explains. In other words, more than half of the immune system lives in the gut, so nurturing the microbiome is important.
Certain foods also contain nutrients, like antioxidants, zinc, and fiber, which play specific roles in the immune system. "That's why it is critical to focus on nutrition and the foods that we eat on a daily basis," Davar says.
As for specific foods that help support the immune system? Experts have plenty of recommendations.
1. Citrus fruits
"It's this great antioxidant that helps to banish free radicals," Maya Feller, M.S., R.D., CDN, said in a mindbodygreen podcast episode. "When we're exposed to so many people and so many viruses, getting a little dose of vitamin C is incredibly helpful."
Papaya is another good source of vitamin C, with about 88.3 mg per cup, according to the U.S. Department of Agriculture (USDA) food database.
It also contains a digestive enzyme called papain, which helps break down proteins in the GI tract. This component helps manage bloat and constipation to support overall gut health, according to one study. As mentioned before, a healthy gut equals a healthy immune system.
According to physician and researcher William Li, M.D., kiwis activate all five health defense systems in the body: angiogenesis, regeneration, the microbiome, DNA protection, and immunity. They also contain fiber, potassium, antioxidants, and about 75 mg of vitamin C.
How to use: Blend into a smoothie, eat on its own, or use to top yogurt.
Studies have shown the liquid extracted from elderberries may limit activity against infections. "In general, elderberries are an excellent source of antioxidants, which help to maintain a strong immune system," functional medicine doctor Tiffany Lester, M.D., previously told mbg. "Especially against viruses."
How to use: Take as a supplement or syrup.
Acai is rich in antioxidants, vitamins, minerals, polyphenols, and flavonoids, Davar tells mbg. All of which have been shown to protect against oxidative stress, and certain conditions, like cardiovascular disease, metabolic syndrome, and age-related neurodegenerative disorders.
"Because these beneficial phytonutrients get cleared from the body quickly, it is important to consume plant foods daily for optimal health," she adds.
How to use: An acai breakfast bowl.
"Watermelon is high in antioxidants, vitamins, and lycopene, which is protective of heart health," Davar says. It's also high in citrulline, which converts to nitric oxide in the body. This molecule has been shown to support endothelial function and enhance athletic performance, according to one study.
Plus, watermelon contains about 92% water, and adequate hydration is important for overall health, especially in hot summer months.
7. Red peppers
Red bell peppers contain antioxidants like beta-carotene and lycopene. "Interest in carotenoids, particularly lycopene, has grown rapidly owing to studies suggesting a role in human health and disease," says one study in the journal Antioxidants. It contains anti-inflammatory properties that have benefited chemotherapy patients and people with cardiovascular and neurodegenerative diseases, the study authors write.
How to use: In a tomato shakshuka, on top of a sandwich, wrap, or salad, or mixed into a pasta dish.
According to Kristine Gedroic, M.D., author of A Nation of Unwell and integrative medicine doctor, broccoli is loaded with immune-boosting benefits. "Not only is it rich in critical nutrients like vitamin C and zinc, but it also contains a natural chemical called sulforaphane that has been shown to boost the activity of key immune cells called T-cells and reduce inflammation in the body."
Additionally, researchers identified a chemical called 3,3'-diindolylmethane (DIM) in broccoli. This property increases the levels of immune-regulating cytokines in the blood, she adds.
Spinach is a good source of antioxidants, like beta-carotene, vitamins A and K, and lutein, Maggie Moon, M.S., R.D., previously told mbg. Many of these antioxidants have been studied for their ability to modulate the immune response. Similar to watermelon, spinach is also a hydrating food with about 90% water content, she adds.
Mushrooms are nutrient-dense veggies that work well in place of meat-based dishes. They have been studied for their medicinal properties, both when eaten or taken in tincture or supplement form. According to immunologist Heather Moday, M.D., mushrooms harbor antibacterial and antiviral properties naturally because they need them to survive in the wild.
"Some mushrooms are a rich source of selenium, magnesium, and zinc, all of which may play a direct or indirect role in their anti-influenza properties," she adds.
How to use: Replace meat in plant-based dishes, make mushroom soup, sauté with soy sauce and eat as a side or add to a stir-fry.
11. Sweet potato
Sweet potatoes are a great source of vitamin A, which "can enhance the organism's immune function and provide an enhanced defense against multiple infectious diseases," according to one study. Sweet potatoes are also high in fiber, which helps feed the microbes in the gut, supporting healthy digestion.
How to use: Roast them, add to a smoothie, or make one of these easy dinners.
"Most nuts are good for your health because they're rich in nutrients like protein, healthy fats, and fiber," Gedroic says. But almonds, in particular, are rich in vitamin E, which supports immune-enhancing T-cells, she explains.
How to use: Snack on them, toast them to give a salad or rice pilaf some crunch.
Both chicken and turkey are complete proteins, meaning they contain all nine essential amino acids, including histidine. Histidine contains antioxidant and anti-inflammatory properties and has been shown to protect against chronic diseases. It also helps activate histamine, which helps produce red and white blood cells—both of which play a primary role in the immune system.
When you're already sick, chicken soup usually hits the spot. Not only is it comforting, but one study found chicken soup may also contain anti-inflammatory properties that help manage symptoms of respiratory infections.
How to use: Make chicken soup, roast chicken, or have a turkey or chicken sandwich.
"Shellfish, especially oysters, are the best source of immune-boosting zinc, which also helps to balance blood sugar levels," Davar says. Just 3 ounces of cooked oysters provides 74 milligrams, according to the USDA. That equals 673% of your daily value (DV).
How to use: On a salad, tossed in a pasta, or added to a seafood soup.
15. Sunflower seeds
Sunflower seed is a great source of healthy polyunsaturated fats and antioxidants like vitamins A and E, Davar says. They're also rich in magnesium, which helps promote quality sleep—a critical factor in immune health and energy levels.
How to use: Top smoothies, salads, or yogurts, or simply snack on them.
According to Gedroic, fermented foods, like yogurt, are some of the best foods to eat for overall health.
"Once in the gut, these bacteria produce antimicrobial compounds called antimicrobial peptides (or AMPs) that help to fight bacteria, fungi, viruses, and infections," she says. "As such, these compounds also seem to stimulate the immune system, which aids in its perpetual fight to stay healthy."
She recommends looking for yogurt with live cultures, such as Bifidobacterium and Lactobacillus.
Miso is a fermented paste made from soybeans. The key word here is fermented, which gives it similar gut and immune benefits as yogurt. Additionally, one study found miso soup consumption lowers the heart rate in Japanese adults, which may promote both stress management and cardiovascular health.
How to use: Eat as a miso soup; use the paste as a marinade for meat, tempeh, or tofu; add it to a stir-fry for extra umami flavor.
18. Pomegranate juice
Pomegranates have been used medicinally for centuries, mainly for their antibacterial properties. While several studies have demonstrated that pomegranate may reduce viral infections, many of them were conducted in vitro. More research is necessary in vivo to verify the antiviral qualities in pomegranate juice.
Even so, neuroscientist and nutritionist Lisa Mosconi, Ph.D., says pomegranate juice contains nearly the same amount of antioxidant polyphenols as red wine, which can protect brain health and reduce the risk of developing Alzheimer's or dementia.
How to use: Drink on its own, freeze into ice cube trays and blend for a slushie, or freeze into an ice pop.
19. Green tea
Green tea is a proven anti-inflammatory, which has been shown to enhance the quality of life for people living with inflammatory conditions. People who drink tea habitually (at least three times a week) tend to live longer, according to one study.
The polyphenols in green tea help protect the brain, while the antibacterial properties protect against oral disease or bacteria. Additionally, "the EGCG in green tea has been found to be 100 times more potent than the antioxidant power of vitamin C and 25 times more than vitamin E," Natalie Butler, RDN, L.D., previously wrote for mbg.
How to use it: Sip it like tea (hot or iced), or take it as a supplement.
The amount of water to drink in a day varies by person, but across the board, adequate hydration is essential. "Good hydration is critical for immune system function," Roxanna Namavar, D.O., and Catherine Waldrop, M.D., previously wrote for mbg. "Mucous membranes, such as those in the mouth and nose, are the body's first line of defense against viruses. If they become dehydrated, they can't produce their moist coating, which prevents viruses and bacteria from adhering to tissue," they explain.
How to use: Drink plenty!
Spices and herbs
Turmeric contains an active compound called curcumin, which has anti-inflammatory, antioxidant, and antimicrobial properties. One animal study also suggested inhibitory effects of curcumin on viruses, like Zika, dengue virus, and hepatitis B.
It's also been used to treat inflammatory bowel conditions like colitis and irritable bowel syndrome, making it great for the gut, registered dietitian Jess Cording, M.S., R.D., CDN, says. Here's exactly how much to take in a day to experience the therapeutic effects.
Garlic can add flavor to almost any dish, and bonus: It has protective health benefits, too. "This superfood has very strong antimicrobial and antiviral properties," Moday says. "The potent sulfur compound allicin in garlic is known to treat serious GI infections such as SIBO (small-intestinal bacterial overgrowth) and kill parasites and yeast infections."
How to use: At the sign of an infection, Moday recommends eating one raw garlic clove a day or taking a concentrated allicin extract. For everyday use, add to pasta dishes, Brussels sprouts, hummus bowls, or pretty much anything needing a savory kick.
"Ginger contains diverse bioactive compounds, such as gingerols, shogaols, and paradols," one study writes. These compounds have antioxidant, anti-inflammatory, and antimicrobial effects. Ginger has also been shown to manage headache, nausea, and cold symptoms.
How to use: Make this ayurvedic tea, add to a soup, take a ginger supplement.
Supporting the immune system requires a holistic approach. Exercise, sleep, stress management, and, of course, proper hand hygiene all play a role. However, "Food is the No. 1 tool for better health," Gedroic says. "With 70% of our immune cells located in the gut, it makes sense to eat the right foods to nourish the gut—and keep our immunity strong."
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