It is beneficial for your immune system to fight illness by eating foods that nourish your body and are high in specific vitamins. The proverb "An apple a day keeps the doctor away" is accurate since apples are a good source of vitamin C. It is among the most important immune boosters that our bodies need. In addition to apples, foods high in vitamin C that strengthen the immune system include oranges, grapefruits, tangerines, strawberries, bell peppers, spinach, kale, and broccoli. Visit Medplus right away to strengthen your immune system with one of their vitamin C immune boosters.