Many of the diseases associated with the ageing process and with older age appear to be caused by compounds called free radicals. These are highly reactive by-products of oxidation, normal biological processes within the body that use oxygen. Free radicals help fight infection and are involved in many other processes including blood vessel function. The body has mechanisms to deal with excess numbers of these reactive particles. If the body is not functioning properly, however, unchecked free radicals can cause damage.
In addition environmental pollutants such as cigarette smoke, smog, ultraviolet radiation, pesticides, even some food additives, over-exercising and stress can all create extra demands for antioxidants to neutralize the free radicals.
Free radicals can cause damage to:
- The lens of the eye, leading to cataracts, and the macula at the rear of the eye, causing age-related macular degeneration
- Nerves and brain, leading to Parkinson′s disease.
- The cardiovascular system. Oxidation of LDL cholesterol causes atherosclerosis.
- Genetic DNA, leading to mutations within cells that can cause cancers of linings within the body such as the throat, stomach and colon, and skin, lungs and cervix.
- Cell mitochonchria, leading to impaired energy production.
The body′s natural antioxidant system appears to decline with age. It is not certain whether this decline is associated with reduced intake of natural antioxidant nutrients from the diet, impaired absorption or perhaps increased needs associated with age.
Prevention or minimisation of free radical damage can be achieved by:
- Avoiding exposure to environmental pollutants
- Introducing antioxidant rich foods into the diet
- Supplementing with antioxidant nutrients including the vitamins A (as beta-carotene, the vegetable form of vitamin A), C and E.
From population and supplementation studies, it appears that the protective benefits of these antioxidant vitamins are at levels that can not be obtained from an average diet. For example the amount of vitamin E required to slow the progression of heart disease appears to be a level greater than 400 iu (compared with the recommended dietary intake of around 15 iu).
Other antioxidants include selenium and glutathione; zinc is involved in antioxidant enzymes systems. Herbs such as milk thistle, ginkgo, bilberry and grapeseed all have plant flavonoid compounds that have a protective antioxidant action within the body.