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Free radicals and the antioxidant defense system


Identifying nutrients (chemicals) that play a role in the antioxidant defense system

Free radicals are highly reactive and unstable oxygen (nitrogen) intermediates released during normal chemical reactions in the body.During the metabolic process of energy production in the mitochondria of a cell, oxygen is reduced to water.On some occasions, this reduction is not complete and oxygen ions with a single electron in the outer orbit are released.

Usually, there is a paired set of electrons in the outer orbit.The free radicals thus released, begin to seek out an electron from surrounding tissues so as to become paired.
As the free radical becomes stable after its electron has been paired, the tissue from which it got the electron becomes damaged.The antioxidant defense system is the inborn system in the body that checks these free radicals.They do so by donating an electron to the free radicals and neutralize them.Tissues and nutrients that are frequently attacked by free radicals are lipids, (LDLs), proteins in the lipid by-layer cell membranes, carbohydrates and Deoxy ribo Nucleic Acid (DNA).

More often than not, the antioxidant defense system neutralizes and stabilizes the free radicals completely and prevents tissue damage.However, on certain occasions, the ability of the defense system to neutralize the free radicals becomes compromised and they accumulate and cause damage.This happens when the amount of free radicals in the tissues and circulation is more than the available antioxidant.


The main free radical produced in the body is the superoxide free radical.When these accumulate as a result of an overwhelmed antioxidant defense system, the superoxide free radicals can react with free fatty acids in a chain reaction to form fatty acid hydro-peroxides and other free radicals.As these accumulate in the absence of antioxidants, the surrounding tissues will begin to suffer from oxidative stress damage.

Components of the antioxidant defense system:
These are the
The vitamin antioxidant defense system.
The enzyme antioxidant defense system.
The mineral antioxidant defense system.

1. The Vitamin antioxidant defense system is made up of Vitamins E, C and A (the carotenoids).
Vitamin E: Being a fat-soluble vitamin is found predominantly in the lipid membranes of cells and organelles.In these membranes, Vitamin E neutralizes fatty acid hydro-peroxide free radicals.It prevents lipid oxidation in cell membranes and protects them against damage.

This vitamin protects against heart disease, cancer and age related conditions such as macular degeneration. It also plays a significant role in testosterone production and spermatozoa maturation.It is a must use for men with low sperm count and reduced libido.Plant sources of vitamin E include: Vegetables: spinach, kale and collard greens.

Nuts: almonds, pistachios, pecans, walnuts and hazel nuts.
Seeds: pumpkin seeds, sunflower seed and sesame seed.
Fruits: avocado.
Seafood/fish: shellfish, shrimps, Cray fish, oysters, salmon and herring.
Oils: olive oil, wheat germ oil, sunflower oil, grape seed oil, canola and corn oil.
Vitamin C: This is the predominant antioxidant in the extracellular fluid compartment.
It neutralizes free radicals by “donating” electrons to them.
Vitamin C also donates electrons to Vitamin E antioxidants that have lost their electrons to free radicals.
In doing so, Vitamin C helps to regenerate Vitamin E and prolongs its ability to prevent lipid damage in the cell membrane.

Sources of Vitamin C:
Fruits: citrus fruits, tomatoes, strawberries, pawpaw and mangoes.
Vegetables: Brussels sprouts, lettuce, spinach, potatoes and cruciferous vegetables such as cabbage, cauliflower and broccoli. Red and green peppers also contain Vitamin C.
Vitamin A (beta carotene)
This is a fat-soluble vitamin, a powerful antioxidant that operates optimally in the fat laden cell membrane.
It prevents lipid oxidation of the lipids in the cell membrane.
Vitamin A is required for vision and as an immune booster.
It can also enhance skin health and acts as a protection against cancer and ageing.

Sources of vitamin A include:
Vegetables: carrots, dark green leafy vegetables such as spinach, kale, Mustard greens, Collard greens, Turnip greens, beet greens and broccoli. Other types of vegetables that are high in vitamin A are Romaine lettuce, pumpkin, sweet red, yellow and green peppers and peas.
Fruits: mango, paw paw (papaya), cantaloupe melon, dried apricots and squash.
Fish/seafood: tuna, mackerel and oysters.
Oils: cod liver oil. What type of food should we eat so as to reduce the level of destruction by oxidative stress. Find out in next Thursdays edition of the Guardian Newspaper.
Happy New Year.

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