Ageing and Longevity

Ageing is inevitable. Ageing is the outcome of both environmental and genetic factors resulting in a decline in function leading to increased vulnerability to disease and death. The chapter provides an overview of the perplexing problems of ageing and longevity. The mitochondria and the telomeres have important roles in cell fate and ageing. When too many critically short telomeres accumulate, cell death (apoptosis) or irreversible growth arrest (cellular senescence) results. Over the years there have been numerous theories on ageing. The evolutionary theories of ageing are now considered by many gerontologists as the basis for the explanation of the ageing process. Summarily rejected, programmed ageing is clearly conflicting with the mechanics of the evolution process. Recent developments have however strikingly altered this, and programmed mammal ageing now has a better evolutionary basis than non-programmed ageing. Life expectancy has increased dramatically, and overall women live longer than men. The centenarians are increasing in numbers globally. Genetic factors account for approximately 20–30% of the overall variation in adult lifespan, and genetic influences on lifespan are least prior to the age of 60 but increase thereafter. Very long life beyond 90 years appears to have a strong genetic basis. The most researched ways to increase longevity is dietary restriction. Several studies among the elderly have shown that the overall Mediterranean diet pattern is associated with longer survival.