Some of the ingredients in our favorite dishes help fight infection and cancer. Sweet potatoes (like carrots, squash and pumpkin) pack the antioxidant beta-carotene, promoting healthy skin. Collard greens are loaded with immune helpers vitamins A and C and zinc. Garlic bumps up immune response and lowers cholesterol. Black-eyed peas are loaded with zinc. Tomatoes, especially if cooked or canned, are loaded with lycopene, an antioxidant that fights prostate cancer.