What is a free radical?

Model of atom

It is not a punk group or crazed politician, but a danger to every living human being. Free radicals have been implicated in several chronic diseases including heart disease, rheumatic disease, some cancers, alzheimer's disease, various liver disorders and many other aging related illnesses.

Atoms are the basic building blocks of more complicated structures called molecules. The simplest molecules consist of just a few atoms held together such as hydrogen (H2), oxygen (O2) and water (H20).

Model of molecule of water.

Most molecules contain an even number of electrons. For example, hydrogen, the smallest and lightest atom, has only one electron but when combined with another hydrogen atom this pair of atoms, a molecule, now has an even number of 2 electrons. The hydrogen atoms share their electrons.

If this sharing of electrons, a bond, is broken then the atom will have an unpaired electron and becomes a free radical. Typically, this process involves oxygen and is called oxidation. The state of an unpaired electron is highly volatile and short lived. These radicals attempt to combine with one another or steal electrons from other types of atoms in order to have a stable even number of electrons

If this radical reacts with a stable molecule, such as a fatty acid in your cells membrane or a piece of your DNA, they can abstract a part of that molecules electrons. This generates new radicals which in turn go on to react with other molecules creating a chain reaction. At high temperatures this process is particularly rapid and prominent which is why high temperature processing of oil leads to rancidity.

Lipids that are damaged by free radicals, lipid peroxides, are deposited into the blood vessels resulting in the development of atherosclerosis.

Heat, sunlight, radiation, and chemicals in cigarette smoke all promote free radicals. This is why people who worship the sun are prone to skin cancer and one mechanism of how cigarettes promote lung cancer.

The body has certain built in protections from free radicals. Antioxidant nutrients include vitamin A, alpha carotene, beta carotene, lycopene, lutein(s), vitamin C, vitamin E, and coenzyme Q10. The body also has enzymes such as superoxide dismutase and ecatalase which help destroy free radicals.

Of the nutrients, vitamin E is the most important antioxidant in the protection of lipids against free radical damage. the incidence and progression of coronary artery damage is related to the dose of vitamin E and its protection against free radical damage to lipids.