7 Foods That Fight Back: Immune System Boosters

Your immune system can use all the help it can get. Even when it’s not cold and flu season, or when the novel coronavirus is a raging threat, keeping your immunity in good shape is a smart idea. In addition to practicing well-studied healthy habits including getting adequate sleep, prioritizing exercise, and using stress-relieving strategies, you can supercharge your immune system by noshing on nutrient-rich foods.

For better immune system booster, here are some of the best foods to put on your plate:

1. Some Types of Seafood Offer Immune-Boosting Omega-3 Fatty Acids

The omega-3 fatty acids found in some types of fish — such as salmon, sardines, herring, and mackerel — help enhance the functioning of immune cells, says Sparta, New Jersey–based Erin Palinski-Wade, RD, author of 2-Day Diabetes Diet and consultant for Swisse Wellness.

Palinski-Wade adds that DHA, a type of omega-3, may enhance the activity of white blood cells, which further strengthens immunity. That’s backed up by a study suggesting that this effect may not only be significant but also happens fairly quickly — within a week, those researchers found.

2. Healthy Proteins Bolster Disease-Fighting White Blood Cells

The National Institutes of Health (NIH) notes that zinc — a mineral abundant in meats like oysters, poultry, seafood, beef, and lamb — works with the protein found in meat to strengthen the immune system. In fact, certain types of immune cells, including white blood cells, can’t function without zinc, according to a review published in December 2016 in the Archives of Biochemistry and Biophysics.

Whether you get your protein from lean meats or vegan or vegetarian options such as tempeh or tofu, making sure you get some at every meal is helpful for keeping your energy and your strength up, suggests McKenzie Caldwell, MPH, RDN, based in Charlotte, North Carolina. She notes that the recommended daily allowance (or minimum amount needed) for protein is 0.8 grams (g) per kilogram of body weight. (To convert to kilograms, divide weight in pounds by 2.2.)

For the most heart-healthy option, choose lean protein. According to the National Heart, Lung, and Blood Institute, lean protein has 55 calories and 2 to 3 g of fat per serving. Examples include 1 ounce (oz) of dark meat chicken with the skin removed, 1 oz of roast beef, and low-fat cheese that has a maximum of 3 g of fat per oz.

3. Dark Chocolate’s Magnesium May Strengthen Antibodies to Fend Off Disease

Plenty of vitamins and minerals play a role when it comes to immune function, but one particular standout is magnesium, according to an article published in 2017 in Molecular, Genetic, and Nutritional Aspects of Major and Trace Minerals. Your immune system is made up of numerous components, including proteins like antibodies, lymphocytes, and macrophages, which all work together to repel invaders like viruses. Palinski-Wade notes that magnesium plays an important role by improving how each of these protein types function.

Previous research has noted, for example, that magnesium helps lymphocytes bind to invaders so they can be removed from the body and helps prevent antibodies from being impaired.

The Cleveland Clinic notes there’s a breadth of foods with ample amounts of magnesium, from pumpkin seeds and spinach to avocados and brown rice.

Perhaps the sweetest surprise on that list? Dark chocolate that contains between 70 and 85 percent cocoa comes in at about 65 milligrams (mg) per ounce, notes the U.S. Department of Agriculture. According to the NIH, the daily value (DV) of magnesium is 420 mg, so 1 oz offers about 15 percent of the DV and can help you reach this goal. Just keep in mind it’s a treat — so indulging in moderation is crucial.

4. Citrus and Leafy Greens Provide Vitamin C, a Key Nutrient for Good Immunity

Vitamin C may help protect the body against oxidative stress, and that helps support immune function, says Palinski-Wade. Oxidative stress happens when there is an imbalance of healthy antioxidants and harmful substances called free radicals in the body, research shows. Oxidative stress is associated with an increased risk of various health conditions, including stroke, cancer, and diabetes, a study suggests.

As a type of antioxidant, vitamin C is a free radical scavenger and enhances immunity by supporting cellular function, among other benefits, notes an article published in November 2017 in Nutrients.

Choose foods that are loaded with this vitamin. According to the NIH, foods with vitamin C include oranges, lemons, strawberries, blueberries, tomatoes, broccoli, leafy greens like kale, and bell peppers. To help retain vitamin C in your food, enjoy it raw when possible. Vitamin C is heat sensitive, so cooking can reduce the amount of this nutrient that your body can take in, according to an article published in April 2018 in Food Science and Biotechnology.

5.Nuts and Seeds Supply Immunity-Supportive Vitamin E, Selenium, and Magnesium

For a filling snack that’s also a big-time help to your immune system, reach for a handful of nuts or seeds. Not only do they have magnesium, but they’re also rich with vitamin E, an antioxidant that’s been shown to improve the body’s ability to fight off bacteria and viruses, according to the NIH.

Plus, it doesn’t take much to get the benefits, Caldwell notes.

“Just one Brazil nut packs more than 100 percent of your daily selenium needs, a mineral that can strengthen your immune system,” she says. Indeed, according to the NIH, 1 oz of Brazil nuts (about six to eight nuts) provides 989 percent of the DV of selenium.

Other options like sunflower seeds, almonds, walnuts, and pecans can give you that vitamin E boost with just a small handful, and they’re a tasty addition to salads and other dishes, says Caldwell. They’re versatile, too, since you can roast them for a snack or make your own homemade nut flour, as the Healthy Maven shows in one of her recipes.

One caveat to keep in mind is that portion control is essential when it comes to nuts. They’re a healthy food but are calorie dense, so overindulgence could contribute to weight gain, says Caldwell.

6. Garlic and Onions Contain Potential Antiviral Properties

Garlic gets that distinctive smell from sulfur compounds, says Palinski-Wade, and regardless of whether you love the aroma, it offers protective benefits to your health and immune response, she notes. That’s because when garlic is crushed or chopped, it produces allicin, which previous research has highlighted for its antiviral and antibacterial properties.

Onions have a substance called quercetin, she adds, which may help regulate histamine response and contains antiviral properties, according to a study published in January 2016 in Viruses.

Looking for a powerful immune-driven dinner? Whip up some fresh pasta sauce with garlic and onions, plus tomatoes for that vitamin C addition, she suggests. This recipe from Taste of Home can show you how.

7. Yogurt Aids Gut Health, Which May Positively Affect Immunity

“Yogurt is rich in probiotics, the good bacteria that support gut health,” says Palinski-Wade. Johns Hopkins notes that a huge proportion of the immune system is actually in the gastrointestinal tract.

According to a study published in May 2017 in Nutrients, eating yogurt daily can improve immune function because it increases the body’s production of antibodies that fight off viruses. To avoid added sugar, choose plain, unsweetened yogurt.

Other Tips to Boost Your Immune System

Let’s say you load up on all this good stuff and still get socked with the effects of a virus. It happens. But continuing to eat healthily can often help shorten the duration of symptoms if you have a mild case of whatever you’ve caught, says Caldwell.

Keep Eating
“Most important is continuing to eat enough food overall,” Caldwell notes. “We might not be able to totally prevent getting sick by eating well, but if you’re not getting enough nutrients, and especially not enough protein, you’re going to lack the energy to fight it off.”

Skip the Sugar and Fat
Also, avoid sugar when you can. Sugar can trigger inflammation in the body, research indicates, and when your system is fighting against that, your immune system may not have enough power to combat outside stressors such as pathogens and viruses, according to a preliminary animal study published in February 2014 in The Journal of Immunology.

“In addition, high amounts of saturated fat and trans fat in the diet can increase inflammation in the same way, and that weakens the immune response,” says Palinski-Wade. These are found in foods like fatty cuts of beef, poultry skin, baked goods, butter, and whole milk, according to the USDA.

Drink More Water
“Stay hydrated” has become the new mantra for pretty much everything from losing weight to boosting energy, and it does provide some magic for improving health overall, says Columbus, Ohio–based Tiffany DeWitt, RD, a senior research scientist at healthcare company Abbott.

Proper hydration levels can help multiple bodily systems, including immunity, research shows. Also, the Mayo Clinic notes, if you’re already on the cusp of a cold, drinking water can loosen congestion.

Although many people may see juices — especially orange juice — as an effective hydration strategy, and good for the immune system, nutrition researchers caution that these are sugar bombs, and there’s no proof that OJ prevents or shortens illness.

Your best bet is water, says DeWitt. Electrolytes from beverages like zero-sugar Gatorade can be helpful for allowing your body to absorb fluids better, she adds, but you can also get these through foods without artificial sweeteners, like bananas, avocados, Greek yogurt, nuts, kale, and spinach.

Enjoy Your Food
Whether you’re feeling under the weather or not, eating mindfully can be helpful, simply because you’ll slow down, feel less rushed, and truly enjoy your food, Caldwell says. Stress has been linked to poor immune functions, according to a study published in October 2015 in Current Opinion in Psychology, so see your meals as a chance to chill.

Although healthy eating can boost your immune system, it can lift your spirit and nourish your sense of well-being, too.