Chlorine (Cl) has 17 protons and 17 electrons. Again the 'shell' system demands two electrons in the inner layer, eight in the next and in chlorine an unbalanced seven electrons (remember eight is the ideal) are found in the outer 'shell'. When sodium and chlorine are brought together, the 'odd' electron in sodium latches on to the seven in the chlorine to create a perfect 'shell' of eight electrons.

This process of combination creates a salt in which sodium and chlorine are bound together (in this case as table salt, NaCI) in a crystalline form. The sodium which has lost its free spinning electron (see above) is therefore now a positive ion, and this is expressed as Na+, while the chlorine which has gained an electron has become a negative ion, expressed Cl-. Chelation (pronounced key-lay-shin) is a natural interaction between an organic compound which has two or more 'available attachment points' (scientifically termed 'reactive sites') in its outer shell, with which it can link (co-ordinate) with a metal which happens to have two free electrons in its outer shell. It is axiomatic that a true chelation reaction has two or more such bonds or links. Together the organic compound (chelating agent) and the metal form a stable ring-like structure when they combine.

You (or indeed any living thing) could not survive without the constant benefits of chelation taking place, all the time, throughout your body. Digestion and assimilation of foods involves, for example, the ongoing process of chelation in which your body uses protein substances (amino acids) to chelate with minerals for transportation to their destinations, or in which blood cells latch on to, and thus acquire, iron. Indeed, haemoglobin is a chelate of iron (as is the enzyme catalase, which your body uses to 'switch off' the free radical activity of hydrogen peroxide). When you eat meat or green vegetables which contain iron, after the digestive process has released the iron from the food in which it is bound it has to be combined (chelated) with amino acids (protein fractions) so that it can be carried through the intestinal mucous membranes into the bloodstream.

However, if you drink tea at the same meal, the tannin in the tea will chelate with the iron (forming insoluble iron tannate) before it gets a chance to be absorbed, thus depriving your body of the iron. Should you, though, take some ascorbic acid (vitamin C) or eat vitamin C-rich food at the same meal as an iron-rich food, this will chelate with the iron and actually enhance and speed its absorption. The iron, once in the bloodstream, is released from the proteins with which it was chelated for transportation, so that it can recombine, in another chelating process, with blood chemicals to form transferrin which is then stored for later use.

Literally tens of thousands of body processes, involving the formation and function of enzymes, hormones and vitamins constantly utilize similar chelation mechanisms. Similarly, countless examples of natural chelation are found in relation to plant life; for example, chlorophyll is a chelate of magnesium which has been processed during photosynthesis.

The word itself is derived from the Greek word (chela) which describes the prehensile claw of a scorpion or crab. This graphically evokes a picture of one substance grabbing or clutching and embracing another, as the chelation process takes place. Chelation therapy is the extension of this natural process to enable the removal from the body of undesirable ionic material by the infusion, or taking orally, of an organic compound which has suitable chelating properties.