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The foods you eat influence so many important bodily processes, including your immune system. In fact, this is one instance in which eating the right foods to boost immunity may actively strengthen your body\u2019s ability to fight off invaders. According to research in Frontiers in Nutrition<\/a>, nutrition plays an essential role in maintaining the optimal immune response to viruses, bacteria, and other illnesses.<\/p>\n Why is adjusting your diet one of the best ways to strengthen your immune system naturally<\/a>? Because the digestive tract houses 70% of the immune system and a large part of the gut microbiome, explained Mary Weiler, Ph.D., R.D.<\/a>, a retired nutrition scientist. Nourishing your gut microbiome with foods that contain the nutrients your good bacteria need to thrive will subsequently support optimal immune health. \u201cRemember the saying, \u2018You are what you eat?\u2019 It might sound silly, but as it relates to your immune system, it\u2019s true,\u201d Weiler said.<\/p>\n Meet the experts: Mary Weiler, Ph.D., R.D.<\/a>, a retired nutrition scientist; Brea Lofton, M.S., R.D.N.<\/a>, a registered dietitian at the digital health company Nourish; William Boisvert, Ph.D.<\/a>, a professor of medicine in the Center for Cardiovascular Research at the John A. Burns School of Medicine in Honolulu; David Katz, M.D.<\/a>, director of Yale University’s Prevention Research Center.<\/p>\n Read on for 30 immune-boosting foods nutrition experts want you to enjoy on a regular basis, whether you\u2019re battling a virus or feeling healthier than ever.<\/p>\n Foods that boost immunity<\/p>\n According to our experts, these foods are particularly rich in the types of nutrients that assist your body\u2019s ability to stave off harmful pathogens.<\/p>\n Yogurt <\/p>\n \u201cThink of probiotics as the \u2018good bacteria\u2019 in the gut, helping influence the microorganisms that live in the digestive tract,\u201d explained Weiler. A review published in Foods<\/a> confirmed that yogurt and other fermented dairy products seem to improve both gut health and immune system function. Be sure to pick up containers free of excess added sugar\u2014plain varieties (which you can flavor with honey and fresh fruit) are your best bet, but anything with less than 8 total grams of sugar is a wholesome option.<\/p>\n Oats and barley <\/p>\n These grains contain beta-glucan, a type of fiber that helps fight disease by stimulating immune cells, according to research in Pharmaceutics<\/a>. Fiber in general also provides nourishment for healthy gut bacteria to thrive and thus supports the immune system, Weiler explained.<\/p>\n Garlic <\/p>\n This potent onion relative contains the active ingredient allicin, which fights infection and bacteria. A review in Frontiers in Immunology<\/a> confirmed that allicin has “anticancer, anti-diabetic, anti-inflammatory, antioxidant, antimicrobial, immune-boosting, and cardioprotective properties.”<\/p>\n Shellfish <\/p>\n Selenium\u2014plentiful in shellfish such as oysters, lobsters, crabs, and clams\u2014helps white blood cells produce cytokines, proteins that help clear flu viruses out of the body. Multiple studies<\/a> have found that selenium is a powerful immunomodulator, or regulator of immune system health and function.<\/p>\n Chicken soup <\/p>\n Yes, it’s more than an old wives’ tale. A review in the journal Nutrients<\/a> that evaluated the use of soup to treat respiratory infections found that it improved levels of inflammatory biomarkers, plus reduced the severity of symptoms and the duration of the illness. Why? The soup\u2019s salty broth keeps mucus thin the same way cough medicines do, while added spices, such as garlic and onions, can increase soup\u2019s immune-boosting power.<\/p>\n Turmeric <\/p>\n \u201cTurmeric contains curcumin, a compound with anti-inflammatory properties that can help support a healthy immune system,\u201d said Brea Lofton, M.S., R.D.N.<\/a>, a registered dietitian at the digital health company Nourish. Lofton added that studies have found that turmeric has potential as a therapeutic agent for conditions such as arthritis, cancer, and cardiovascular disease, in part due to its immune-modulating properties.<\/p>\n Tea <\/p>\n Black tea contains L-theanine<\/a>, an immune-boosting amino acid. Both black and green tea also contain catechins, antioxidants that reduce inflammation, mitigate liver damage, and lower cholesterol, according to research in Food Science and Biotechnology<\/a>.<\/p>\n Beef <\/p>\n Zinc is essential for the development of white blood cells, the intrepid immune system cells that recognize and destroy invading bacteria, viruses, and assorted other bad guys, said William Boisvert, Ph.D.<\/a>, a professor of medicine in the Center for Cardiovascular Research at the John A. Burns School of Medicine in Honolulu. Beef is a good source of zinc<\/a>, as are milk and beans.<\/p>\n Pork <\/p>\n It\u2019s important to get the recommended 8 to 11 mg of zinc<\/a> per day to keep the immune system functioning properly, said Weiler. She recommended adding pork as a zinc source in a balanced diet, be it a grilled pork chop or tenderloin.<\/p>\n Almonds <\/p>\n Almonds are high in vitamin E, containing around 7 mg per serving, explained Lofton. Vitamin E is an antioxidant that can help protect cells from damage and therefore, potentially prevent illness.<\/p>\n Sweet potatoes <\/p>\n You may not think of skin as part of your immune system. But this crucial organ serves as a first-line fortress against bacteria, viruses, and other undesirables. To stay strong and healthy, your skin needs vitamin A. \u201cVitamin A plays a major role in the production of connective tissue, a key component of skin,\u201d explained David Katz, M.D.<\/a>, director of Yale University’s Prevention Research Center. One of the best ways to get vitamin A into your diet is from foods containing beta-carotene (which gives them a vibrant orange pigment), like sweet potatoes, carrots, squash, canned pumpkin, and cantaloupe.<\/p>\n Ginger <\/p>\n \u201cGinger can help boost immune function by reducing inflammation in the body,\u201d said Lofton\u2014effects that have been confirmed by research in Frontiers in Immunology<\/a>.<\/p>\n Kale <\/p>\n Along with orange produce, dark, leafy greens like kale contain vitamin A<\/a> and can help bolster immune function.<\/p>\n Bell peppers <\/p>\n There\u2019s a reason you\u2019re told to load up on vitamin C<\/a> when you get sick: The nutrient is great for your skin, which acts as a barrier between your body and harmful organisms. On top of that, studies show<\/a> that not getting enough vitamin C can actually impair your immune response and make you more susceptible to infections. The Academy of Nutrition and Dietetics<\/a> adds that vitamin C can help reduce the severity and length of your symptoms if you fall ill.<\/p>\n Broccoli <\/p>\n Lofton said broccoli is rich in vitamins A and C, as well as fiber, which work together to support a healthy gut microbiome and immune system.<\/p>\n Eggs <\/p>\n You already know that vitamin D is important for your bones, since it helps you absorb calcium properly\u2014but it\u2019s also essential for a healthy immune system. Why? Scientists have found that your immune cells actually have vitamin D receptors, which are important for regulating your body\u2019s natural defense mechanisms and keeping them functioning smoothly, according to research in Experimental and Molecular Pathology<\/a>.<\/p>\n While the sunshine vitamin is hard to come by naturally through your diet, foods high in vitamin D<\/a>, such as eggs, can help you meet your daily intake. The National Institutes of Health (NIH) recommends<\/a> a minimum of 600 international units (IUs) of vitamin D for most adults daily, but other accredited organizations suggest aiming much higher.<\/p>\n Fortified cereals <\/p>\n Not a fan of eggs? Certain cereals are fortified with vitamin D, which \u201chelps to activate immune cells and properly regulate their function, and is critical for innate and adaptive immunity,\u201d said Weiler. Just check that nutritional info when you\u2019re shopping the cereal aisle.<\/p>\n Mushrooms <\/p>\n People around the world have turned to mushrooms for a healthy immune system for centuries, and contemporary researchers now know why. Research in Biomedicine and Pharmacotherapy<\/a> shows that phytonutrients in mushrooms have an immunomodulatory effect, increasing production of immune cells that identify invaders. They\u2019re also another great source of vitamin D.<\/p>\n Bone broth <\/p>\n \u201cBone broth is made by simmering bones and connective tissue from animals, which releases nutrients such as collagen, amino acids, and minerals,\u201d explained Lofton. \u201cThese nutrients can help support immune function and overall health.\u201d<\/p>\n Kefir <\/p>\n Like yogurt, kefir, a fermented yogurt drink, contains gut- and immune-boosting probiotics. A review published in Cureus<\/a> notes that kefir may protect people from infections and improve immune and metabolic health.<\/p>\n Fatty fish <\/p>\n Salmon, mackerel, and herring are rich in omega-3 fatty acids, which reduce inflammation and strengthen various types of cells produced by the immune system, per research in the International Journal of Molecular Sciences<\/a>.<\/p>\n Citrus <\/p>\n Citrus fruits like oranges and grapefruit are high in vitamin C, a nutrient that is, like the orange juice commercials say, essential for immune function. \u201cVitamin C builds healthy skin and tissue to resist entry of bacteria and other germs,\u201d said Weiler. \u201cThe vitamin also contributes to the rapid increase in B cells and T cells, two white blood cells that play a role in secreting antibodies and killing off infections.\u201d<\/p>\n Sunflower seeds <\/p>\n More than just a salty summer snack meant for baseball games, Lofton pointed out that sunflower seeds are high in vitamin E, an antioxidant that can help protect cells from damage.<\/p>\n Blackberries <\/p>\n Blackberries are high in antioxidants, plant compounds that can help shield the body from environmental stressors and germs, said Lofton. They also contain fiber and vitamin C, which support a healthy immune system and gut.<\/p>\n Chicken breast <\/p>\n \u201cProtein is an important building block for antibodies and immune cells and supports wound healing,\u201d said Weiler. \u201cGenerally, try to aim for 25 to 30 grams (g) of protein at every meal to get what you need over the day.\u201d To do so, she recommended chicken breast as a premium source.<\/p>\n Legumes <\/p>\n If you eat a plant-based diet and are looking to up your protein intake for optimal immune function, Weiler recommended having a legume salad or a side of baked beans. According to the United States Department of Agriculture<\/a> (USDA), a cup of cooked lentils boasts 18 g of protein.<\/p>\n Celery <\/p>\n Celery is high in fiber, \u201cwhich provides nourishment for beneficial bacteria in the gut to support the immune system,\u201d said Weiler. The satisfyingly crunchy snack also has a high water content, which can boost hydration for immune and digestive systems in need. \u201cHydration is critical to maintaining mucus membranes, which aid in the trapping of bacteria and viruses and assists with their release via coughing and sneezing,\u201d Weiler explained.<\/p>\n Kiwi <\/p>\n Kiwi contains vitamin E and water, which translates to protection and hydration essential to all bodily systems. \u201cVitamin E has been shown to increase the percentage of T cells, the white blood cells that seek out and destroy harmful invaders,\u201d added Weiler.<\/p>\n Blueberries <\/p>\n Blueberries are abundant in polyphenols, an antioxidant that protects against inflammation. That\u2019s why the superfood has been studied<\/a> for its many health benefits, including those for gut and immune health.<\/p>\n Brazil nuts <\/p>\n Brazil nuts are high in selenium, explained Weiler. Selenium, via selenoproteins and enzymes, has antioxidant properties that help to break down peroxides that can damage tissues and DNA, per Harvard T.H. Chan School of Public Health<\/a>.<\/p>\n How the immune system functions<\/p>\n Think of your immune system as your body\u2019s gatekeeper. It serves as protection against any foreign substances (such as bacteria, viruses, parasites, or fungi) that may enter your body and cause harm.<\/p>\n Here\u2019s how it works: Your immune system is a vast network of organs, proteins, and cells\u2014like your skin, bone marrow, blood, and mucosal tissue\u2014that join forces to distinguish healthy cells from not-so-healthy ones. How? When a germ makes its way into your body, your immune system receives signals that something isn\u2019t quite right. From there, it responds by sending your body\u2019s frontline defense force of white blood cells (or immune cells) to attack and destroy anything that it interprets as risky or dangerous, according to the NIH<\/a>.<\/p>\n