Your immune system plays a key role in overall health and wellness. Unfortunately, your immune health can be compromised by destructive free radicals and oxidative stress from environmental and lifestyle factors. Eating foods rich in immune-boosting nutrients is essential to supporting your overall health. To help keep your immune system strong, include these immune boosting foods in you diet.

Chicken Soup
Chicken soup may do more than just soothe a sore throat and keep you hydrated, it may keep your airways healthy, as well. Researchers at the University of Nebraska found that chicken soup deters movement of inflammatory white cells, which can help prevent colds by blocking the accumulation of cells in the bronchial tubes. The researchers believe the ingredients in chicken soup provide anti-inflammatory properties that help reduce congestion. For added immune-boosting powers, make your own chicken soup with healthy additions like oregano, garlic, cilantro, carrots or onions.

Broccoli
Broccoli is packed with immune-boosting nutrients like vitamins A, vitamin C, and “the master antioxidant” glutathione. Glutathione protects the body from free radicals by fortifying immune health and boosting antioxidant protection. A recent study in the European Journal of Nutrition showed that daily 1000 mg oral supplementation of glutathione was found to increase glutathione levels in the blood and boost immune strength. To maximize the benefits of vitamin C and glutathione, foods are best eaten in the “raw” form. If you’re not a fan of raw broccoli, try making a fresh broccoli salad with shredded cheese and other veggies tossed in a vinaigrette dressing, or go for a Thai- or Chinese- inspired broccoli slaw to advance your immune health.

Sardines
Fatty fish is rich in omega-3 fatty acids, which research shows helps reduce the risk of heart disease and inflammation in the body. In addition, a new study published in the Journal of Leukocyte Biology shows that omega-3 fatty acids may also help boost the immune system by enhancing the functioning of immune cells. While salmon, tuna, and trout are all good sources of omega-3 fatty acids, sardines may trump their fishy counterparts. Sardines are not only high in omega-3 fatty acids, due to their small size they are extremely low in contaminants such as mercury. Sardines also provide other important nutrients to keep your immune system running strong. For example, a ¼ cup serving of BELA sardines in olive oil contains 120 calories, 13 grams of protein, and is packed with calcium and vitamin D for good health. Try pairing sardines with salad greens, avocado halves, walnuts, pistachios, or goji berries for added nutrition and flavor.

Yogurt
Regularly eating “good bacteria” (or probiotics) can help improve digestion and strengthen your immune system. Look for “live and active cultures” on the yogurt label as research shows they may stimulate your immune system to fight disease. A study from the University of Vienna in Austria showed that a daily yogurt (7 ounces) was as effective in promoting immunity as taking pills. Another benefit, yogurt and other dairy foods are also fortified with vitamin D. Recent research has linked low levels of vitamin D to an increased risk of flu and colds. For optimal health, stay away from yogurts with added sugars and artificial sweeteners. A sweetened yogurt can easily have as much added sugar as a soda. Instead, choose a plain yogurt and add your own natural sweetness like fresh berries, dried fruit or a touch of honey. In addition to yogurt, fermented vegetables like sauerkraut and vinegar-based pickles, as well as Kefir (a yogurt-based drink) provide probiotics to keep your system running strong.

Mushrooms
Mushrooms have long been known to promote a healthy immune system. They are rich in selenium, B vitamins, and antioxidants, which are all important nutrients to keep your body running strong. In addition, recent research shows that mushrooms increase the production and activity of white blood cells, which is beneficial when having to fight off infection. Maitake, reishi, and shiitake mushrooms seem to provide the largest benefit to immunity. For maximum immune-boosting benefits, aim for an ounce or two a day. Mushrooms work great in salads, pasta sauces, sautés, omelets, soups, on pizza, or as a meat substitute to ground beef.

Tea
Whether you prefer green or black tea, your immune system is in luck. Both provide disease-fighting antioxidants (polyphenols and flavonoids) that protect against free radicals and help destroy them. One study showed that catechins, a particular type of polyphenols in tea, kill certain viruses. Another Harvard study showed that people who drank 5 cups a day of black tea for two weeks had 10 times more virus-fighting interferon in their blood than other who drank a placebo hot drink. Both black tea and green tea are rich in L-theanine, an amino acid thought to help enhance immunity that’s found in both regular and decaf versions.

Patricia Bannan is a Los Angeles-based registered dietitian specializing in nutrition and health communications.  She is the author of "Eat Right When Time Is Tight: 150 Slim-Down Strategies and No-Cook Food Fixes." Follow her on Twitter, Instagram, Pinterest, and LinkedIn.