Being deficient in any of the nutrients, vitamins & minerals can weaken your immune system. The immune system is made up of a network of cells, tissues, and organs that work together to protect the body. Proteins plays an important role in building the immune system stronger while other essential elements like vitamins A, C, D, E, zinc & selenium play a vital role too. Here are 12 foods that can make your immune system strong: Sweet Potatoes High in – Vitamins A & C Kale High in – Vitamins A & C Butternut Squash High in – Vitamins A & C Beets High in – Vitamins A & C Leeks High in – Vitamins A & C Parsnips High in – Vitamins E & A Canned Fish/Wild Salmon High in – Protein, Fatty Acids, Vitamin D Almonds & Walnuts High in – Protein, Vitamin E, Fatty Acids Sunflower Seeds High in – Protein, Vitamin E, Fatty Acids Oysters High in – Protein, Zinc & Selenium Mushrooms High in – Zinc, Selenium, & Vitamin D Yogurt High in – Protein, Vitamin A, & Probiotics.