Our immune system plays a key role in protecting us from a variety of ailments. It actually serves as the defense system of our body and helps fight against a number of disease causing microorganisms. It comprises special cells, tissues, organs and cell products that battle against various pathogens including bacteria, virus and fungi. However, the immune system needs certain nutrients to run smoothly. Lack of these essential nutrients or other factors such as age, stress and pollution can hamper immunity. A weakened immune system makes a person vulnerable to a number of diseases. Hence, it is very important to keep our immune system healthy to prevent various health problems.