Topics: Immune system, Antioxidant, Oxygen Pages: 5 (934 words) Published: April 18, 2014

Antioxidants are natural compounds that are present in some foods, which help stabilize free radicals (a harmful unstable molecule produced naturally in the body as a bi-product of oxidation) and prevent them from damaging other cells.

Importance of antioxidants
Free radicals that are formed in the body are highly dangerous, as they are unstable molecules with an odd number of electrons. Since they have an odd number of electrons they seek and steal electrons from other molecules in the body, causing damage to the cell membranes or DNA in cells, leading to destruction of cells and metabolic processes in the body. As the free radicals steal electrons and destroy the healthy cells and stable molecules, they cause more free radicals to form. This forms a sort of chain process and can eventually result in deterioration of the immune system and lead to diseases like heart diseases and cancers. This is why antioxidants are required. They bind with the free radicals, neutralizing them and preventing them from attacking cells and forming destructive chain reactions, thereby preventing the risks of heart diseases and cancers. They are important to ensure that the immune system is kept intact and the body is guarded from the risk of developing various other harmful diseases, like Alzheimer's disease, Parkinson’s disease, arthritis, cataracts, diabetes, kidney disease, and age-related blindness, which are all said to be possible outcomes of the devastation caused by free radicals (Fontenot, 2011).

Some major antioxidants
Antioxidants are mostly plentiful in green leafy vegetables and fruits, as well as nuts, whole grains and some meats. Few of the major sources of antioxidants are Vitamin A, Vitamin C, Vitamin E, Beta-carotene, Selenium and Lycopene. Sources of specific antioxidants include:

allium sulphur compounds – leeks, onions and garlic
anthocyanins – eggplant, grapes and berries
beta-carotene – pumpkin, mangoes, apricots, carrots, spinach and parsley catechins – red wine and tea
copper – seafood, lean meat, milk and nuts
cryptoxanthins – red capsicum, pumpkin and mangoes
flavonoids – tea, green tea, citrus fruits, red wine, onion and apples indoles – cruciferous vegetables such as broccoli, cabbage and cauliflower isoflavonoids – soybeans, tofu, lentils, peas and milk

lignans – sesame seeds, bran, whole grains and vegetables lutein – green, leafy vegetables like spinach, and corn
lycopene – tomatoes, pink grapefruit and watermelon
manganese – seafood, lean meat, milk and nuts
polyphenols – thyme and oregano
selenium – seafood, offal, lean meat and whole grains
vitamin A – liver, sweet potatoes, carrots, milk, and egg yolks vitamin C – oranges, blackcurrants, kiwifruit, mangoes, broccoli, spinach, capsicum and strawberries vitamin E – vegetable oils (such as wheatgerm oil), avocados, nuts, seeds and whole grains zinc – seafood, lean meat, milk and nuts

zoochemicals – red meat, offal and fish

(Deakin University of Australia, 2013)

Antioxidants and the prevention of cell injury:
Oxidative stress is when the body has an overabundance of free radicals which the body cannot protect itself from. It results due to an imbalance of free radicals and the defense of antioxidants. It leads to cell deterioration and damage of DNA in cells which can lead to cancer (MD A.M., 2012). Reactive oxygen species (ROS) comprises of all the highly reactive, oxygen-containing molecules, including the free radicals. Some ROS include the hydroxyl radical, hydrogen peroxide, the superoxide anion radical, nitric oxide radical, singlet oxygen, hypochlorite radical, and various lipid peroxides. These are capable of reacting with membrane lipids, nucleic acids, proteins and enzymes, and other small molecules which is how cell membranes can get destroyed and body enzyme functions and metabolic processes inhibited (MD A.M., 2012). Antioxidants are greatly accountable for the prevention...
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