By what mechanisms do free radicals cause damage and disease?

Free radicals contribute to many different diseases. Chemically, a substance is oxidized when electrons are removed and reduced when electrons are added. All chemical reactions involve the transfer of electrons. The body generates energy by gradually oxidizing its food in a controlled manner and storing it in the form of chemical potential energy, called ATP.

Ironically, this energy-generation mechanism which is so essential to life can also set the stage for cell damage. The oxidation of foodstuffs is like a controlled fire which liberates energy but can also let sparks fly, giving rise to potential damage. The sparks in this analogy are free electrons escaping the transport system. These unpaired electrons readily form free radical molecules which are chemically reactive and highly unstable.

It is these free radical molecules which rapidly react with other molecules, setting off a chain reaction of free radical formation, somewhat similar to an atomic explosion. So now we have this molecule which is missing an electron and is dying to get its hands on an electron to help fill its need. This free radical now goes and steals an electron from another molecule that is more willing to give one up and thus it becomes satisfied, but now the victim molecule has become a free radical! This goes on for quite some time. We therefore call this process the chain reaction of free radicals.

Cell membranes are made of unsaturated lipids. The unsaturated lipid molecules of cell membranes are particularly susceptible to this damaging free radicals process and readily contribute to the uncontrolled chain reaction. Oxidative damage, another name for the chemical reaction that free radicals cause, can lead to a breakdown or even hardening of lipids, which makeup all cell walls. If the cell wall is hardened (lipid peroxidation) then it becomes impossible for the cell to properly get its nutrients, get signals from other cells to perform an action (such as firing of a neuron) and many other cellular activities can be affected. In addition to the cell walls, other biological molecules are also susceptible to damage, including RNA, DNA and protein enzymes.

The primary site of free radical damage is the DNA found in the mitochondria. Mitochondria are small membrane-enclosed regions of a cell which produce the chemicals a cell uses for energy. Mitochondria are the "energy factory" of the cell. Every cell contains an enormous set of molecules called DNA which provide chemical instructions for a cell to function. This DNA is found in the nucleus of the cell, which serves as the "command center" of the cell, as well as in the mitochondria. The cell automatically fixes much of the damage done to nuclear DNA. However, the DNA in the mitochondria cannot be readily fixed.

Therefore, extensive DNA damage accumulates over time and shuts down mitochondria, causing the cells to die and the organism to age.⁷
Hence, this free radical generation process can disrupt all levels of cell function. This is why free radical damage is thought to be such a basic mechanism of tissue injury. It damages us at the cellular level.

The more toxic metals in your body, the higher the free radical activity.

Now here's the kicker. Heavy metals in your body multiply those free radicals chain reactions several thousands, possibly several million times. When a free radical molecule hits a metal atom in your body, the effect is multiplied many-fold. This is partly why it is so important to remove toxic metals from your body through chelation.

Free radicals are increased in activity and quantity by bumping into toxic metals in the body. Thus, toxic metals are a cause of free radicals. Several hundred years ago we did NOT have the burden of toxic metals in our bodies that we now do, and we also did not have such an exposure to free radicals. If you remove the toxic metals from the body, you then greatly reduce the activity and the number of free radicals.

It is also clear that environmental agents initiate free radical problems. The toxicity of lead, pesticides, cadmium, ionizing radiation, alcohol and cigarette smoke may all be due to their free radical initiating ability.

References

1. Karlsson, J. Introduction to Nutraology and Radical Formation. In: Antioxidants and Exercise. Illinois: Human Kinetics Press, 1997, p. 1-143.
2. Goldfarb, A. H. Nutritional antioxidants as therapeutic and preventive modalities in exercise-induced muscle damage. Can. J. Appl. Physiol. 24: 249-266, 1999. [Abstract]
3. Sjodin, T., Y.H. Westing, and F.S. Apple. Biochemical mechanisms for oxygen free radical formation during exercise. Sports Med. 10: 236-254, 1990. [Abstract]
4. Del Mastero, R.F. An approach to free radicals in medicine an biology. Acta. Phyiol. Scand. 492: 153-168, 1980.
5. Strand, Ray D. MD, What Your Doctor Doesnt Know About Nutritional Medicine May be Killing You. Nashville: Thomas Nelson Publishers, 2002, p. 20-30.
6. D. Harmon, J. Gerontol. 11, 298-300 (1956).
7. Takayuki Ozawa in Understanding the Process of Aging, edited by Enrique Cadenas and Lester Packer (Marcel Dekker, New York, 1999), pp. 265-292.

Contents extracted from:

• http://www.healthchecksystems.com/antioxid.htm