Antioxidant

I had the the feeling that some people do not know, what is Antioxidants ? and that it is so important in our life.
So I selected that article .I hope it will be nice ,and useful .

First of all what is Oxidation ? 
Oxidation is one of these things

1.  Gaining of Oxygen .
2. Losing of Hydrogen .
3. Losing of Electrons .

An antioxidant is a molecule capable of inhibiting the oxidation of other molecules.
Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When the chain reaction occurs in a cell, it can cause damage or death of the cell because of the end result of the reaction.
 Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions. They do this by being oxidized themselves, so antioxidants are often reducing agents such as thiols, ascorbic acid ( the precursor of vitamin C) or polyphenols.
Although oxidation reactions are crucial , and important for life, they can also be damaging ;  hence, plants and animals maintain complex systems of multiple types of antioxidants, such as vitamin C, and vitamin E as well as enzymes . Low levels of antioxidants  cause oxidative stress and may damage or kill cells .
As oxidative stress appears to be an important part of many human diseases .
Antioxidants are widely used as ingredients in dietary supplements and have been investigated for the prevention of diseases such as cancer, coronary heart disease and even altitude sickness.
Although initial studies suggested that antioxidant supplements might promote health, later large clinical trials did not detect any benefit and suggested instead that excess supplementation is harmful.


Types Antioxidants 
Antioxidants are classified into two broad divisions, depending on whether they are soluble in water (hydrophilic) or in lipids (hydrophobic).

• Vitamin C or Ascorbic acid

It is a monosaccharide oxidation-reduction catalyst found in both animals and plants . Ascorbic acid is required for the conversion of the procollagen to collagen , so it is important for the skin .humans must obtain it from the diet ,it is produced in the human body and is acquired in the diet .
Found in,   Fresh Fruits and vegetables .

• Vitamin E. 

Like Vit C   it is produced in the human body and is acquired in the diet .

Found in ,Vegetable oils

• Uric acid. 

• Melatonin .

• Carotenoids ,carotenes .

Found in , Fruit, vegetables and eggs

• Melatonin .

is a powerful antioxidant  .