The vitamin responsible for boosting the immune system is Vitamin C, also known as ascorbic acid. This antioxidant showcases several important functions in the body, particularly in the immune system. It helps stimulate the production of white blood cells, which are essential for fighting infections. Additionally, Vitamin C protects cells from oxidative stress and supports the skin's barrier function for overall defense against pathogens. Consuming enough Vitamin C through a balanced diet rich in fruits and vegetables, such as oranges, strawberries, and bell peppers, is crucial for maintaining a healthy immune response.