Free radicals are constantly attacking body proteins, carbohydrates, fats and DNA, causing potentially serious damage if left unchecked.

They come from within the toxic by products of metabolism and from without from radiation, car exhausts, heat and lack of oxygen. You can't avoid free radicals, but you can limit the numbers produced by your body and limit their effect on your cells. Daily antioxidant supplements in the form of vitamins such as A (beta carotene 3000-5000 mg), C (1000 mg) and E (at least 400 iu); minerals like zinc (10-50 mg) and selenium (200 mcg); amino acids such as cysteine (500 mg), or herbal preparations like grapeseed extract and aloe vera help minimise the damage.

While the elderly normally produce less gene DHEA, French research has shown that supplementing with chromium (200 mcg daily) can help boost production of natural DHEA.

As an alternative to supplements, try eating more apples, peanuts, broccoli, brewer's yeast, mushrooms, grape juice and spices such as cinnamon all rich in chromium.

EFAs (omega-3 and omega-6 fats) are also important. Dietary fats are necessary for a healthy nervous and immune system. Instead of just taking supplements, try also boosting your intake of oily fish such as salmon (Eur J Clin Nutri, 1992; 46: 397-404; Med Clin North Am, 1989; 73: 1531-50).

Brain tissue is particularly susceptible to free radical attack, because it generates more of these toxins per gram of tissue than does any other organ (FASEB J, 1995; 9: 526-33), so increasing antioxidants could help maintain your mental faculties.

There is also evidence that loss of cognitive function is preventable through good nutrition, especially with the consumption of B12, B6 and folic acid (Am J Clin Nutri, 1992; 55: 1237S-43S).

Lower your salt intake

Our modern diet is grossly over salted. Instead of just cutting out salt at the table, try lowering your consumption of salty processed foods.

Switch to a plant based diet

A plant based diet is low in salt and high in antioxidant vitamins, which boost immunity and slow corrosion in ageing cell membranes. It is also high in B vitamins, which may protect the heart. Eating plants means getting

plenty of cancer fighting phytochemicals, bone saving calcium and the fibre necessary to keep the colon healthy and modulate blood sugar.

Believe in the benefits of exercise

Regular exercise can lower your risk of cancer and improve immune system function (promoting more white blood cells and increased levels of immunoglobulins). Exercise can also help to keep the mind healthy (J Am Geriatr Soc, 1988; 36: 29-33; J Intern Med, 1995; 238: 423-8) and improve mental health, especially with regard to depression (Sports Med, 1994; 17: 108-16).

Stay in the trim

Dr Paffenbarger's Harvard study showed that a lean body mass was associated with a lower overall mortality rate (N Eng J Med, 1993; 328: 538-45).

Keep your mind active

Mental stimulation preserves both mind and immune system function. In a famous study of nursing home residents, those given the freedom to make their own decisions about their environment showed a significant and swift improvement in mental and physical function. At follow up one and a half years later, only 15 per cent of the active group had died, as opposed to 30 per cent of those who were not given the freedom to exercise free will (J Person Soc Psychol, 1977; 35: 897-902).