As we age, damage accumulates in our DNA, through side-effects of the normal activities of life. The damage causes the information in our DNA to become corrupted over time and thus contributes to the ageing process.
The main cause of DNA damage is oxidation. Each cell in our bodies contains hundreds of mitochondria, like tiny batteries in our cells which use oxygen to produce energy. However, this also produces free radicals which damage our DNA, contributing to normal ageing.
When a gene is copied in new cells, any damage is also replicated and so the build-up of mistakes increases over time, like a biological game of Chinese Whispers. This affects our body’s ability to repair itself as efficiently as it did in our earlier years.