There are some things that science can tell me that I’m not sure I want to know. For example, I’m not sure I want to know the sequence of my own genome and my projected risk of developing any particular, currently incurable diseases. There are some things it is better not to know, particularly if there is nothing you can do about it anyway. Until recently I would have put telomere length into this category as well. Short telomeres are an indicator of biological age and are associated with increased susceptibility to diseases of aging. And stress, such as could be caused by worrying about how short your telomeres are, is known to make them even shorter. So why find out? It turns out that there are some things under our control that can positively affect telomere length.
Telomeres are nucleoprotein structures at the end of chromosomes that protect them from damage and ensure that genetic information is not lost during cell division. DNA polymerases cannot replicate DNA at the ends of chromosomes effectively, and without the protective effects of telomeres a small amount of chromosomal DNA would be lost with each cycle of cell division. The stretches of repetitive telomere DNA prevent progressive shortening of the chromosome, but are themselves shortened with each cell division. Telomere shortening limits the number of times that a cell can divide. Somatic cells are capable of a finite number of divisions, a number known as the Hayflick limit. Once cells reach that limit, they die. This limit is associated with telomere length. Once telomeres reach a critical length, cellular senescence is triggered, and a cell stops dividing and dies. Because of this, telomere length can act as a gauge of cellular or “biological” age. Continue reading