Understanding Free Radicals and Antioxidants

What are free radicals? Why are they damaging to the human body? And how does vitamin E and the other antioxidant nutrients help protect the body against free radical damage? We?ll attempt to answer these questions and help you understand why eating 5-8 servings per day of anti-oxidant rich fruits and vegetables can benefit your health. But first, a little background?

Background: A Brief Look at Chemical Bonding

To understand the way that free radicals and antioxidants interact, you must first understand a bit about cells and molecules.  So here’s a (very) brief refresher course in Physiology/Chemistry 101:  The hu[Oxygen atom]man body is composed of many different types of cells. Cells are composed of many different types of molecules. Molecules consist of one or more atoms of one or more elements joined by chemical bonds.

As you probably remember from your old high school days, atoms consist of a nucleus, neutrons, protons and electrons. The number of protons (positively charged particles) in the atom?s nucleus determines the number of electrons (negatively charged particles) surrounding the atom. Electrons are involved in chemical reactions and are the substance that bonds atoms together to form molecules. Electrons surround, or “orbit” an atom in one or more shells. The innermost shell is full when it has two electrons. When the first shell is full, electrons begin to fill the second shell. When the second shell has eight electrons, it is full, and so on.

[O2 molecule]The most important structural feature of an atom for determining its chemical behavior is the number of electrons in its outer shell. A substance that has a full outer shell tends not to enter in chemical reactions (an inert substance). Because atoms seek to reach a state of maximum stability, an atom will try to fill it?s outer shell by:

  • Gaining or losing electrons to either fill or empty its outer shell
  • Sharing its electrons by bonding together with other atoms in order to complete its outer shell

Atoms often complete their outer shells by sharing electrons with other atoms. By sharing electrons, the atoms are bound together and satisfy the conditions of maximum stability for the molecule.

Source: Understanding Free Radicals and Antioxidants

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