Free Radicals and Antioxidants

Free radicals are small oxygenated molecules, such as hydrogen peroxide (H2O2), that possess strong oxidizing properties. Examples include:

Superoxide: O ₂^-
Peroxide:    O₂^2-
Hydroxide radical .OH - note this is a radical not the OH^- ion. The dot '.' indicates an unpaired electron, rather than a free electron pair not cancelled by a proton in the nucleus.

An ion has a charge and a radical does not. A free radical is an atom or molecule with an odd number of electrons, so that there is an unpaired electron in the outer shell. It has no electrical charge.

Free radicals can do an enormous amount of damage to your body if not controlled, so how are they produced?

Generation of Free Radicals

Your Own Metabolism
In any reaction involving oxygen and oxygenation, you are liable to find free radicals being formed as a by-product. The process within your body that involves oxygen the most is cellular respiration: the process whereby glucose and oxygen are used within the mitochondria of your body cells to generate energy.

In actual fact, we don't generate energy, because energy can be neither created nor destroyed. What we do in cellular respiration and within the mitochondria is to convert the energy in our food into ATP energy (adenosine triphosphate) - however that is another topic discussed elsewhere on this website.

Free radicals are by-products of this process. Generally your body can handle these free radicals through the generation of the powerful antioxidant, glutathione, in the liver. However, they still do some damage, and aging is partially due to free radical attack of the membranes of the cells in your body.

However, it is when such oxygenated molecules are introduced to your body from external sources that you will need some help from the antioxidants in your diet.

Pollution
One of the major external sources is pollution. You can ingest pollution from a number of sources, including:

• Traffic fumes


• Industrial emissions


• Tobacco smoke


• Heating appliances


• Pesticides

Each of these produces free radicals and once you ingest them by breathing, swallowing or through skin absorption, they can play havoc with your cells. However, there is another source just as dangerous to us and that is difficult to avoid:

UV Radiation
Ultra-violet radiation from strong sunlight or even sun-beds generates free radicals in your skin. That is one reason why naturally white-skinned people living in hot areas such as Northern Australia and California often have tough leathery skin on their faces and hands. Their skin cells are destroyed, and they have deep valleys and troughs, and also that leathery weather-beaten appearance.

Effects of Free Radicals

Their effects can be devastating to your health. They oxidize everything in their paths. To explain that, I will say a few words about their chemistry and you can skip this if chemistry is of no interest to you.

Electron Shells
Electrons circulate atoms in distinct shells or layers: their orbits are like the planetary orbits, the planets orbiting the sun equating to the electrons orbiting the nucleus of the atom. Each orbit can have a maximum number of electrons, after which another layer or orbital shell is generated.

Electrons do not orbit the nucleus in one path round it, but cover the entire shell, or surface, of the sphere around the nucleus. You can look on each electron orbit as being a shell, every point of which is equidistant from the nucleus. The more electrons an atom has then the more such concentric shells encompass the nucleus.

Unpaired Electrons
One law of chemistry and physics is that electrons must be paired for stability. Each electron is spinning, just like the earth spins a full circumference each day. A spin can be clockwise around its axis (positive or + spin) or counter-clockwise (negative or - spin). For each positively spinning electron there must also be a negatively spinning one or that orbit will be out of kilter.

A radical has one electron only in the top shell. If any electrons are lost they must be lost from the outermost orbit, because orbits are filled with available electrons from the center out. Hence the odd one must be in the outer shell and is all set to react with other molecules. This free electron is very active, and highly oxidative, an oxidizing agent being one that steals an electron from another stable molecule.

When atoms come together to form molecules (entities containing two or more individual atoms) the electrons that each possesses are shared between them, so that at least the outermost electrons circulate around the entire molecule. It's actually more complex than this, but that description will suffice for now.

Skin Damage

A molecule with a free electron is called a free radical, and its sole purpose in its short life is to steal an electron from the nearest possible donor. Within your body that is generally a molecule that makes up the membranes of your cells. These are formed from what are known as unsaturated lipids, and when these have an electron removed from them by this highly reactive molecule they will readily give it up - an end up a free radical itself, because it is now short of an electron! And so on, and on, and on. . .

The net result is the destruction of enough cells to make a difference to your health or to the appearance of your skin. Oxidative stress refers to the oxidation of biological molecules by free radicals, and is basically an oxidizing reaction where electrons are taken from a molecule. Another form of oxidation is by acids that offer atoms and molecules an extra proton. This type of oxidation, where a free radical grabs an electron from a molecule of your cell walls, causes these walls to become hard and inflexible (leathery skin).

Damage to DNA and RNA DNA and RNA are the molecules of life. Some of the most significant damage done to your body is the oxidation of your DNA and RNA. Most know what DNA is but what is RNA? While DNA (deoxyribonucleic acid) carries the blueprint of your genetic make-up, RNA (ribonucleic acid) contains a fingerprint of your DNA.

Your body uses particular segments of your RNA as a blueprint to produce complex protein molecules for many purposes (muscle tissue, enzymes, etc.), and if this gets damaged then your body will begin to malfunction. Hence, one reason for the importance of antioxidants to your overall health.

Atherosclerosis
Cholesterol is essential for your body, and if you had none you would die. It is used by your body as a band-aid and for the generation of hormones in your adrenal glands. Among the hormones for which cholesterol is essential are testosterone, estrogen, progesterone, cortisol, DHEA and aldosterone. The band-aid refers to the repair of artery walls, cell walls and other parts of your body by cholesterol.

However, cholesterol is fat soluble, so how does your body get it to the areas where it is needed most? This is not a local repair service, but a national one, and cholesterol could be needed anywhere from your brain to your toes to repair cellular damage. It is solubilized by means of lipids: a series of organic molecules that are both water and fat soluble.

Lipids can attach to cholesterol by means of their carbohydrate tails, and then solubilize it by means of its water soluble head. The problem is that if these lipids, known as LDL (low density lipoproteins), become oxidized they also lose their solubility in your blood and precipitate out as LDL cholesterol 'plaques' on the inside of your artery walls. Free radicals can oxidize the LDL cholesterol in your bloodstream/plasma and so render them insoluble.

The result is an ever increasing precipitation of LDL cholesterol that progressively blocks your arteries until even just a small, normally insignificant blood clot can cause a blockage. If this blockage is in a brain artery, that part of your brain can be starved of oxygen and you will suffer a stroke. If the same type of blockage occurs in a cardiac artery, your heart can stop with fatal results.

Prevention of Atherosclerosis
The only way to prevent your LDL lipids from becoming insoluble in your blood plasma is to prevent them from being oxidized. There are generally three ways to deal with problems. Using fire as an example, you need the fuel, oxygen and a source of ignition to start a fire: remove any one of these and no fire can result.

How does that relate to atherosclerosis? If you remove any one of:

• the LDL cholesterol


• the free radicals


• the oxidizing reaction

you can avoid this condition entirely. But you can do none of these for reasons we have just discussed:

• the LDL cholesterol is essential to your body so you cannot remove that
,

• the free radicals are generated in many ways and cannot be removed
,

• the oxidation comes as a matter of course.

So what is the answer to free radicals? Neutralize them!. To do that, add a reducing agent, or an antioxidant. The two terms are basically the same: reducing and antioxidant.

To do that you should eat a diet containing a number of different antioxidants: Vitamins A and E, and many colored fruits and vegetables. Both red and violet, and all the colors in between, indicate the presence of powerful antioxidants such as polyphenols and flavanoids.

There are many of these available, the best being broccoli, capsicums, tomatoes, acai berries, raspberries, blueberries, aubergine, brussels sprouts, kale and many, many more. Each has a good phytochemical content offering the best natural antioxidants you can find.

Most vegetables and some fruits are better cooked, because this makes the antioxidants they contain easier to digest and assimilate into your body. By learning about free radicals and antioxidants, you can do the power of good to your own body.

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