Your body continually replaces its cells. By the billions each day. During this process and through other factors it also produces free radical. In case you have not read prior, a free radical is an atom with a missing neutron. Neutrons must always occur in pairs. Your atom or free radical is not happy with the missing neutron. One possible solution is ingesting antioxidants which lend their neutron to the free radical making them whole again.
Your body produces different types of free radicals, and therefore you need different kinds of antioxidants. The many types of free radicals are generated due to various stimulants such as radiation, pollution, toxic foods, exposure to chemicals, exposure to smell and fumes and even cell death. Knowing your anti-oxidants is therefore essential. The first type is called an allyl sulfide, commonly found in onions, leeks, and garlic. These help women who at risk of osteoporosis and menopause. It also helps reduce the risk of several types of skin cancer. Then you have carotenoids which are found in fruits and vegetables. Carotenoids help prevent blindness, improve your cardiovascular health, prevent tumors from forming and improve the health of your skin. Finally, you have polyphenols which are commonly found in green tea, grapes, and pomegranate. These help prevent cancer, prevent hardening of the arteries, reduce the risk of diabetes, allergies, asthma, and arthritis and also act as anti-inflammatory agents. Resveratrol, for example, is the reason many Doctors recommend that you drink a glass of wine every day.
Naturally, each anti-oxidant plays a different role and protects you from a different kind of potential disease. To immunize yourself completely, you need to vary your diet and ensure that you get all the different types on a regular basis. If you are the kind of person who eats the same kind of food every day, you significantly increase your risks.