Telomeres aren't formed by the same enzyme that replicates our DNA, polymerases; rather, the task falls to an enzyme called telomerase. Telomerase controls not just the generation and formation of telomere DNA, but also how long our telomeres might be. Cells that divide frequently, such as embryonic stem cells, continually produce telomerase. But in most of our cells, the enzyme is inactive. That means that as telomeres shrink, there is no active enzyme ready and able to step in and rebuild them. Every time a cell divides, which over its lifetime is about 50 to 70 times, some of the unique DNA that forms our telomeres is lost in the process. Lose enough telomere DNA and the cell loses its ability to replicate, and when a cell can't divide, it dies.
Shorter telomeres have recently been linked to problems such as illness, premature aging and yes, early death. It's not that the loss of telomeres themselves cause us to age. Instead, researchers theorize that short telomeres may make us more vulnerable to traumas, everything from how the body is able to handle infection to other physical, psychological and environmental stressors.
Researchers have been experimenting with how to activate the telomerase enzyme in an effort to combat the aging process. A study conducted at Harvard Medical School found that when telomerase-deprived mice were given a telomerase activator, they regenerated brain, liver, spleen and reproductive organ cells. A subsequent study conducted at the Spanish National Cancer Research Center found that insulin levels were lowered and skin and hair were fuller in mice that were fed TA-65, a telomerase activator. Could a natural telomere growth supplement be the new fountain of youth?
Perhaps, but researchers also warn that there may be a link between activating the telomerase enzyme and an increase in the risk of developing certain cancers. Cancer cells have a unique ability to turn on the telomerase enzyme and keep telomeres long -- it's that ability to replicate that allows abnormal cancer cells to thrive and spread.
Overall, it's important to remember that there isn't just one reason why we age. Telomeres, however, are an interesting part of the aging puzzle.