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22 Best Immune-Boosting Foods, According to Nutritionists

We asked the experts to weigh in on which are the best foods for naturally improving your immune system.

We all know cold and flu season is no joke, but we bet you don't want to get sick year-round, too, right? It's of utmost importance then that your immune system is strong enough to play defense at all times, and one way to do that is through eating certain foods that can help naturally improve your immune system.

Eating foods that boost your immune system could help keep you healthy during cold and flu season (and every other season, for that matter). Such foods include fruits and vegetables that are rich in vitamin C and zinc—which some studies show may prevent viruses like the common cold when consumed together—and foods that are chock-full of other immune-improving substances such as collagen, probiotics, and vitamin A.

We called upon the experts to provide us with a list of foods that are designed to help your body stay immune to illness and help to naturally boost your immune system. Here are 22 foods that nutritionists eat themselves that can help you improve your immune system year-round. Read on, and for more on how to lose weight, you won't want to miss The Best Ways to Lose Belly Fat for Good, Say Doctors.


Red Bell Pepper

Red yellow green bell peppers

"I hate to brag, but I think I've had one cold in the past 12 or 13 years! Part of it is probably luck, but I think a lot of it has to do with the fact that I eat clean, healthy foods that support my immune system all year long. Red peppers are one of my favorite foods to incorporate into my diet for immune system-boosting benefits. Gram for gram, they have about twice the amount of vitamin C as most fruits and vegetables, including the most famous immune-boosters, oranges. Vitamin C is really important for immunity because it can help reduce the length and severity of colds. It also helps your body make collagen, which keeps your skin healthy, and your skin is your first line of defense against germs. I love red peppers because they're sweet and delicious, and there are so many ways you can eat them. Add them to an omelet in the morning, eat them raw as a snack with a handful of almonds or a scoop of hummus, or slice them up and roast them with a little bit of olive oil, sea salt, and pepper." — Keri Glassman, MS, RD, CDN, founder of Nutritious Life

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Black Elderberry Syrup


"Whole Foods is my one-stop-shop for picking up all my groceries, but also my health supplements. For cold and flu season, I always stay stocked up on Gaia Herbs' Black Elderberry Syrup, which provides 14.5 grams of organic elderberries into a single teaspoon. The syrup also contains organic acerola cherry fruit extract—a rich source of vitamin C to help our immune system during this time. Both my kids have been sick already this fall, but I've been taking Gaia Elderberry Syrup regularly and have avoided getting sick! Bonus is that it tastes delicious, too!"

— Brooke Alpert, MS, RD, CDN, founder of B Nutritious


Sweet Potatoes

Sweet potatoes

"Sweet potatoes contain more than three times the Daily Value (DV) for vitamin A, a good source of vitamin B6, plus some magnesium and vitamin C—an antioxidant."

— Michelle Dudash, RDN, author of Clean Eating for Busy Families



Fresh blueberries plastic pint

"One serving (a handful or a cup) of blueberries provides 16 percent of the daily recommended amount of vitamin C. Not only is vitamin C a key nutrient that helps the immune system work properly, it's also an antioxidant that helps to protect cells from damage, and it's needed for the body to make collagen, a protein required to help wounds heal. I often throw blueberries in a smoothie or make this blueberry chia jam to eat on toast throughout the week."

— Natalie Rizzo, MS, RD, author of The No-Brainer Nutrition Guide For Every Runner


Yogurt and Kefir

Drinkable yogurt kefir

"Yogurt and kefir are great ways to strengthen the immune system by providing the body with helpful probiotics, a set of live bacteria and yeasts that are beneficial to improving digestive health. The immune system is the main link between our gut bacteria and how it influences our health, so having a healthy digestive system is crucial. There are a lot of different strains of probiotics, but the most common is lactobacillus, which is found in yogurt and kefir."

— Gabriele Geerts, RD at Green Chef




"Grapefruit is an excellent food to choose to boost your immune system. It is high in vitamin C (half a grapefruit has 68 percent of your recommended dietary intake) which has antioxidant properties and may boost your cells to fight off bacteria and viruses. Vitamin C is also said to boost immune cells and help you bounce back from a cold faster. If you don't want a cold grapefruit, try baking it by cutting it in half, [and then] bake at 350 degrees for 15-20 minutes and scoop it out to enjoy over vanilla yogurt."

— Jessi Holden, MS, RDN, CSOWM


Roasted Chickpeas

Roasted chickpeas

"Roasted chickpeas have been my go-to snack this winter! Not only are they a great substitute for chips when you get a crunchy craving, but they [also] contain the mineral zinc, which helps strengthen our immune system to fight off bacteria and viruses."

— Erin Marchefka, NDTR


Oil of Oregano


"During the cold winter months, I try to drink a cup of hot water with a few drops of oil of oregano. Oregano is a natural antioxidant, anti-fungal, and antibiotic—which is exactly what your body needs to keep you healthy. By consuming oregano in the concentrated oil form, you reap the most benefits. If you don't like the taste of the drops, supplements can also be purchased in capsule forms."

Marissa Meshulam, MS, RD


Shiitake Mushrooms

Shiitake mushrooms

"Studies show that shiitake mushrooms reduce inflammation and boost the immune system. In Chinese medicine, shiitake mushrooms have been used for many years as an immune booster, being a rich source of copper, selenium, zinc, and vitamins B and D–all vital for a healthy immune system. Shiitake mushrooms take their rightful place as an important food that boosts immunity."

— Julie Mancuso, BA, RHN, founder of JM Nutrition


Sunflower Seeds

Sunflower seeds

"Sunflower seeds contain 35 percent of the daily value for vitamin E, which works as an antioxidant that neutralizes free radicals and may improve immune function. The seeds also contain protein and magnesium."

— Dudash



Asparagus with lemon

"Asparagus is a great source of prebiotic fiber, which is the indigestible plant fiber that feeds the probiotics in your gut. Eating prebiotic fiber helps keep your gut and immune system healthy since 70 percent of your immune system lives in the gut."

— Rizzo


Green Tea

Green tea in mugs

"Not only does hot tea feel soothing on a sore throat, but there can be actual health benefits as well! Due to the way it is processed, green tea, in particular, is very high in specific antioxidant compounds known as EGCG compared with black tea. Additionally, green tea contains an amino acid L-theanine, most notably known for positive effects on brain function, which also is thought to enhance immune function."

— Meshulam



Popcorn bowl

"One of the foods I eat to boost my immune system is popcorn. Most people don't realize that popcorn is high in polyphenols. Polyphenols have similar properties to antioxidants that help prevent cardiovascular disease and some cancers. Studies show polyphenols can reduce some of the oxidative damage caused by strenuous exercise, too. Popcorn contains 300 milligrams of polyphenols per serving, which is more than what is found in most fruits and vegetables! Popcorn is the only food in the American diet that is a 100 percent unprocessed whole grain, which means it's high in fiber—an added benefit."

— Cindy Dallow, PhD, RD



Garlic bulbs and cloves

"Garlic contains the enzyme alliinase, which converts alliin to allicin, a beneficial sulfur compound that is believed to boost immune function and fend off the common cold and flu. The allicin is activated by chopping or crushing and letting stand for 10 minutes and is most bioavailable when consumed raw. I suggest swallowing the minced garlic and following with a squeeze of lemon and a glass of water."

— Geerts



Broccoli on a wooden cutting board

"A chemical called sulforaphane is found in broccoli. This chemical triggers certain immune cells with antioxidant genes and enzymes to fight free radicals and prevent sicknesses."

— Dr. John Gilmer, Ph.D. and Vice President of Research & Development at Active Iron


Pumpkin Seeds


"Pumpkin seeds are rich in zinc, which is a mineral that is well-established for boosting immunity, helping the immune system fight off bacteria and viruses. It also decreases oxidative stress and the generation of inflammatory cytokines. There is even research that finds that a functional food made from pumpkin seeds was shown to reduce social anxiety and insomnia—due to the zinc and tryptophan-boosting serotonin—so we get those added benefits, too. This serotonin boost also helps us feel happier and calmer in the winter months, when winter blues are common."

— Trudy Scott, Food Mood Expert and Certified Nutritionist, author of The Antianxiety Food Solution: How the Foods You Eat Can Help You Calm Your Anxious Mind, Improve Your Mood, and End Cravings




"Turmeric contains an anti-inflammatory called curcumin, which stimulates the activation of main fighting cells of the immune system. These are called T-cells."

— Gilmer


Hemp Seeds

Hemp seeds

"Another important aspect of immune health is zinc, since it helps fight against infection. Zinc isn't in that many foods, but just 2 tablespoons of hemp seeds contain about 20% of your daily needs. Go ahead and add some to your smoothie or oatmeal."

— Rizzo


Oily fish


"Oily fish like salmon, trout, anchovies, and sardines are rich in essential omega-3s, which are a precursor to many compounds that play a defensive role in immune response."

— Dudash




"Clementines are easy to take with you wherever you go. They're packed with vitamin C, which helps prevent colds and fight infections."

— Karen Z Berg, MS, RD, CDN



Eggs in a bowl

"Eggs are one of the few kitchen staples that provide a reliable and convenient source of immunity-boosting lutein. It's a carotenoid that works by enhancing the body's inherent immune response. As an antioxidant, lutein also fights oxidative stress that runs high when we're sick since the body has higher protein needs when we're ill. I also appreciate that eggs are an affordable source of protein. They are quick and convenient to cook, and it's hard to think of a savory dish that isn't made better with an egg on top."

— Maggie Moon, MS, RD, author of The MIND Diet, and owner of MIND Diet Meals



Star anise

"This spice is easily recognized by its distinctive licorice smell. Anise is a triple threat with antibacterial, antifungal, and antiviral properties. It also contains immunity-boosting antioxidants."

— Gilmer 

Cheyenne Buckingham
Cheyenne Buckingham is the former news editor of Eat This, Not That! Read more about Cheyenne