Keep your cold or flu at bay with these seven foods that can boost your immune system.
Of course, there are a whole host of healthy habits that can protect you against illness. As a reminder, the World Health Organization recommends washing your hands frequently, keeping at least three feet of space between yourself and anyone with symptoms, and avoiding touching your eyes, nose, and mouth as general guidelines.
Still, even with these good practices in place, it’s impossible to completely avoid germs. They’re everywhere. Truer still if you work in an office, or travel often. To bolster your immunity from the inside out, here are scientifically-backed foods to support your immune system.
7 Immunity-Boosting Foods
1. Sweet Potatoes
Another reason to celebrate sweet potatoes: They’re full of beta-carotene, which helps increase T-cell activity. (Read: Your body is better able to fight against infection.)  Plus, beta-carotene is a powerful antioxidant to help fight off damaging free radicals.
This fermented drink packs probiotics, including the bacteria bifodobacterium bifidum. Findings show that this particular strain can help boost your immune system and increase antibody levels.  (Bonus: It also helps with your digestion.) Alternatively, this bacterium can also be found in some yogurts, fermented vegetables, and our Gut Instinct probiotic supplement.
A study published in Molecular Nutrition and Food Research found that in conjunction with vitamin D, a compound in blueberries (called pterostilbene) seriously boosted the gene in our bodies that’s associated with immune function.  They’re also high in antioxidants, which help prevent damage to cells.
Sorry, apples: Turns out that a mushroom a day is what actually could help keep the doctor away. A study done at the University of Florida’s Institute of Food and Agricultural Sciences found that eating a four-ounce serving of shiitake mushrooms for four weeks bolsters the immune system . It helps gamma delta T-cells (aka cell receptors that signal your immune system to fire up) function better, and also helps reduce inflammation.
Oats contain a special type of fiber called beta-glucan. Studies show that it can help our infection-fighting blood cells.  In fact, one Norwegian study reports that the antibacterial powers of beta-glucan are even more potent than those of echinacea.
6. Egg Yolks
Egg yolks may have gotten a bad rap in the past for their cholesterol levels. But recent studies have found that the negative connotations are false.  Plus, the yolk contains high levels of zinc, an important mineral when it comes to controlling infections.
A 2013 study found that it helps balance your immune response, preventing your immune system from going overboard when fighting infection, which can cause inflammation that makes you feel worse.  Plus, if you don’t get enough zinc in your diet, it can cause you to be more susceptible to germs and infections. Other foods high in zinc are spinach, oysters, and chickpeas.
7. Citrus Fruits
You’ve likely heard that citrus fruits like oranges and grapefruits are high in vitamin C. As a refresher, vitamin C is a nutrient that helps T-cells (the cells that fight infections and diseases) function optimally. If you don’t get enough vitamin C, your chances of getting sick increase. Oranges have the highest amount of vitamin C, followed by grapefruit, then lemons, and limes.