The Biological Fountain of Youth

A mere millennium ago, the average human died in their twenties. And just a century ago, people only expected to live into their forties. Today, the average American has a lifespan of nearly seventy-nine years. That's nearly doubling our longevity in just over a century.

Biomedical research and regenerative medicine will only lengthen our lives further, but how far? We won't know unless we understand the causes of aging.

A widely accepted theory of aging is evolutionary senescence which means as we age, damage accumulate in our DNA. Then cells are less able to replicate properly and regenerate tissue. In fact, most everyone is familiar with the term, free radical, which shows how damage to our cells over time contributes to aging.

Cells produce free radical molecules when they use oxygen to make energy. Free radicals lead to oxidative damage of DNA and other cellular components. Even though we have protective genes in place to kill off damaged cells, those same processes may also play a role in aging.

An often used example concerns a gene called p53. As we age, it may become excessive in its role of directing damaged cells to die, so that tissues don't regenerate and atrophy.

Our neuroendocrine system may also affect aging and involves hormones. For example, in studies with lab mice, lowering IGF or insulin-like growth factor extended their life.

Ancient philosophers believed we're born with a predetermined amount of vital force. And that when it's used up, we die. Now, it's more complex than that, but could we one day replenish our life force?