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What damages your cells?

Harmful molecules are continually bombarding your body. The worst offenders are glucose (a type of sugar), and free radicals, by-products of energy production. Both can damage the proteins, fats and DNA that make up your cells. When you are young, your body is able to repair most of this damage. But as you get older, the repair process is less efficient. Some researchers think that boosting our natural defences against these chemical onslaughts may lessen the effects of ageing.

Glucose and free radicals can damage your DNA.

Why does glucose age you?

Your body breaks down carbohydrates (for example the starch in bread) into glucose, the simplest form of sugar. Glucose is a vital source of energy, especially for your brain cells. But over time, it can also cause problems. Glucose molecules can stick to proteins, forming 'cross-links' that stop the proteins working properly. Cross-linking can gradually lead to hardened blood vessels, cataracts, damaged nerves and kidneys - all problems of old age.

Our nerves get damaged as we age.

Eat less, live longer?

Mice that are fed 30% fewer calories live longer. Why? Animals (including you) use oxygen to burn fats and carbohydrates to produce energy. But energy production also makes free radicals - molecules that attack your cells. Most of the time, your cells mop up these free radicals, but this becomes less efficient as you get older. The hungry mice may live longer because they are burning less food, and so making fewer free radicals. Many groups of people now restrict their calorie intake in the belief that it will give them longer lives.

Mice that are fed 30 per cent fewer calories live longer.

Recycle more to live longer?

Genes are responsible for spring-cleaning our cells. Some protects cells from stress, others release enzymes to break down toxins. Genes and toxins play important roles in current thinking about ageing. The latest explanation – the ‘Green theory’ of ageing – suggests that how you age depends on the genes that control how well your cells remove and recycle the toxic junk that builds up inside them. A better understanding of these genes may help us find ways of living longer, healthier lives.