If you want to eat healthier to boost your immune system, don’t worry about a complete menu makeover. Just be sure to add these five foods to your diet.

Yogurt: Perfect for a quick breakfast, snack, or added to a smoothie, yogurt’s secret weapon is probiotics (aka “friendly bacteria). It’s naturally present in the digestive system. Yogurt is a supplemental source for probiotics. Researchers at U.C. Berkeley have found that probiotics in yogurt can improve bowel health and help the immune system ward off cold-causing viruses and bacteria.

Japanese Mushrooms: Healthy and tasty, Japanese mushrooms such as shitake and enoki work well in miso soup, sautéed with onions and garlic, or added to pasta sauce served with noodles. Many people eat them because they’re nutritious and have protective health benefits, and research shows that these mushrooms are a good source of vitamin D, which your body needs to fight infection, support muscle function, and maintain cardiovascular health. A study published in the Journal of Alternative and Complementary Medicine also found that mushrooms may help prevent and treat certain types of cancer.

Salmon: Grilled, baked, or smoked, salmon is a delicious main dish for lunch, dinner, or added to egg whites for breakfast. Ever wonder why nutrition experts recommend eating fish at least twice a week? Salmon is loaded with vitamin D and omega-3 fatty acids. These nutrients help strengthen your immune system and protect your brain. A study from Cornell University found that eating wild-caught salmon is healthier because it contains fewer contaminants than farm-raised salmon.

Ginger Green Tea: Drink in some antioxidant-rich goodness with ginger green tea you can order at Starbucks, or make yourself at home, perhaps with fresh ginger and matcha (powdered green tea), but not just because it tastes good. Research shows that the antimicrobial properties of ginger green tea help kill bacteria (including salmonella) and fight infection. It’s also been widely used internally and topically as an antiseptic and anti-inflammatory. In addition, one study found that green tea may help halt the spread of skin cancer and promote skin-cell rejuvenation.

Shellfish: Some of your favorites may include shrimp, lobster, crab, crayfish, and mussels. These shellfish make a nice addition to garden salads, served as a main dish, or added to pasta. Shellfish are low in fat and high in protein, and can help prevent heart disease, control cholesterol, regulate blood pressure, and provide other protective benefits.

Add these five foods to your diet more often. You’ll be healthier and your immune system will be stronger for it.