Eat a Balanced Diet
Eating a balanced and healthy diet is one of the most effective ways to strengthen the immune system. A diet rich in fruits, vegetables, whole grains and lean protein provides the body with the essential vitamins, minerals and nutrients it needs to function properly. Vitamin C, for example, is a powerful antioxidant that helps to boost the immune system by increasing the production of white blood cells that fight off infections. Foods that are high in vitamin C include citrus fruits, strawberries, kiwi, bell peppers and broccoli.