Telomere length

Telomeres form the ends of human chromosomes and protect the chromosome from damage.

Think of telomeres like the plastic caps on the end of shoelaces: if the plastic caps break, the shoelace frays. It’s the same for our DNA. In human cells, the length of the telomere shortens a small amount each time the cell divides.

After many replications, telomeres become critically short, which can lead to ‘genome instability’, and potentially cancerous changes in our DNA. A short telomere acts as a signal for the cell to stop dividing, and to enter a protective state called senescence.

Telomeres shorten naturally with normal aging, but they can shorten faster if we have unhealthy lifestyles, including a poor diet. Therefore, telomere length may be used as an indicator of health, and disease risk.

Figure 1. Left to right: Schematic image showing a human cell with DNA within the nucleus; zoomed image showing a chromosome with telomere caps; cell division and associated gradual shortening of the protective telomere cap.


  • Bull, C. F., Ocallaghan, N. J., Mayrhofer, G., & Fenech, M. F. (2009). Telomere Length in Lymphocytes of Older South Australian Men May Be Inversely Associated with Plasma Homocysteine. Rejuvenation Research, 12(5), 341-349. doi:10.1089/rej.2009.0868