Research into the ageing process shows that about 40 per cent of what affects life expectancy is within our control. Although a good diet can help us to live a longer life (see Altenatives WDDTY vol 8, no 9), the next most important way to live to 100 is to prevent free radical damage.

Free radicals are highly reactive compounds made by the body during normal processes involving oxygen, and there is evidence that a raised level of free radical activity leads to some of the changes associated with ageing. They can damage cell membranes, mitochondria (the"lungs" of cells), DNA and proteins. It is now known that pollutants, such as pesticides, herbicides and many drugs, will react within your body, producing copious amounts of free radicals.

A great deal of scientific evidence implicates free radicals as the main cause of many degenerative diseases (Ann Intern Med, 1987; 107: 526-45; Arch Environ Health, 1976; 30: 231-5; BMJ, 1985; 290: 417-20)

Free radical damage appears to promote brain ageing and degenerative diseases such as Alzheimer's. In an Austrian study, 1,769 participants had their blood antioxidant levels measured and their cognitive performance evaluated. A clear relationship existed between low mental performance and cognitive impairment (such as poor memory) and low blood levels of vitamin E (Am J Epidemiol, 1996; 144: 275-80).

Another double blind study, conducted in the US at numerous centres over two years, studied the effects of vitamin E on in 341 patients with moderate Alzheimer's disease. The basis of comparison used by the researchers was the so called "primary outcome measure" the time it took for death, severe dementia, loss of basic capacity for daily living requirements or the need for institutionalisation to occur, compared with those on a placebo. .

The results showed that the risk of reaching any primary endpoint was 53 per cent lower in the group on vitamin E, compared with the group on placebo.

In the study, vitamin E was also compared with the Alzheimer drug selegiline, and with a combination of vitamin E and selegiline.

In the two year period of the trial, the length of time it took to reach any of the endpoints was increased by 230 days in the vitamin E group, by 215 days in the selegiline only group, and by only 145 days in the group that had vitamin E in combination with selegiline (New Engl J Med, 1997; 336: 1216-22).

Studies conducted in Canada, Spain and Britain have investigated the effects of supplementing with antioxidants (particularly vitamins A, C, and E, as well as some minerals) on the immune function of the elderly. These studies show an increase in natural killer cells (the body's best defence against cancer) and significantly improved immune response (Internat J Vit Nutr Res, 1995; 65: 117-120; Lancet, 1992; 340: 1124-7; Can J Physiol Pharmacol, 1998; 76: 373-80).

Epidemiological studies carried out in Finland, Canada and the US show that cataract risk can be up to 80 per cent lower in a person with high blood levels of antioxidants, particularly beta carotene and vitamin E (Ann N Y Acad Sci, 1989; 570: 372-82; BMJ, 1992; 305: 1392-4).

Three similar studies in the US have linked low antioxidant levels with the risk of age related macular degeneration. One found a 43 per cent decrease in risk in those with high levels of the carotenoids in the diet (J Am Diet Assoc, 1994; 272: 1413-20). Another found that the risk of macular degeneration doubled in those patients with the lowest blood levels of vitamin E (Arch Ophthalmol, 1994; 112: 222-7).

!AHarald Gaier

Harald Gaier is a registered naturopath, homoeopath and osteopath.