The unstable atoms or molecules known as free radicals are produced by the body as a consequence of its normal metabolism, and as part of its natural defence against disease. Sometimes, however, the body over-produces free radicals which may cause serious damage to delicate cellular structures, resulting in inflammation and also the oxidation of blood cholesterol which is then deposited on arterial walls. This situation can be worsened by smoking, a high intake of pesticides, smog, over-exposure to ultraviolet light and even intensive exercise.
Free radicals contain at least one unpaired electron (or negative charge), making them highly reactive. As soon as they are produced, they search for molecules with which they can react, this reaction is called oxidation. Free radicals can oxidise, and so damage DNA and cell membranes, opening the way for cancers and diseases to develop. They are linked to the appearance of brown patches on the skin of elderly people. But although free radicals have been associated with aging, cancer, atherosclerosis, high blood pressure, osteoarthritis and immune deficiency, their role in the development of these conditions is still being researched.
However, it is generally believed that if free radicals reach and attack the DNA in the nucleus of a cell, the cell mutation which can result may cause cancer. It has also been observed that when cholesterol is oxidised by free radicals it is more damaging to the artery that ‘native’ cholesterol, so implicating free radicals in the development of heart disease.
The body has defence mechanisms against free radicals, antioxidant enzymes and nutrients in it cells serve to ‘mop up’ free radicals and render them harmless. Protective nutrients include, iron, zinc, copper, manganese and selenium (which help to make up protective antioxidant enzymes) as well as vitamin A, C and E. Other plant substances also provide protection against free radical damage; these include beta carotene and bioflavonoids.