Our immune systems can be strengthened through good nutrition and healthy lifestyle habits, like following a balanced diet, trying not to stress, getting enough sleep, and regularly exercising. Vitamins A, C, D, and E, zinc, antioxidants, and probiotics boost the immune system along with protein which builds and repairs damaged immune cells. Root vegetables like carrots and sweet potatoes, greens like spinach and kale, nuts, seeds, avocadoes, fatty fish, eggs, and oils are all excellent examples of immunity-boosting foods.