Stress and Telomere Length

Telomeres

telomeres

In the image above, telomeres are highlighted at the ends of each chromosome.

Recent studies show that telomere length, a measure of cellular aging, is strongly influenced by stress.

Telomeres are stretches of DNA at the end of chromosomes responsible for protecting the chromosome. Every time a cell divides its telomeres are shortened. In some cells an enzyme named telomerase replenishes the lost telomerase, but in other cells the telomeres gets continually shorter. Therefore, telomere length can be a good predictor of aging. Eventually, the telomere protection disappears and unprotected genetic material would get cut with each division. Usually, at this point the cell dies.  

Elizabeth H. Blackburn, a researcher at the University of California, San Francisco, shared the 2009 Nobel Prize in Physiology or Medicine for her work on the process of telomere shortening.  Blackburn's current research is looking at telomere length and its association with risk of developing chronic diseases like cancer, heart disease and other illnesses. In addition, Blackburn's work has contributed to a growing plethora of research showing that various lifestyle decisions influence telomere length.

In the Science Talk section of the October 2011 Scientific American, Blackburn says that unpublished research shows that people with higher blood levels of omega-3 fatty acid had much less telomere shortening. 

Stress has been shown to accelerate telomere shortening. A study published in August 2011 found that women who worked full-time had significantly shorter telomeres than those who were not employed (Employment and work schedule are related to telomerase length in Women, CG Parks, et al.). A study published in 2004 found a negative correlation between the number of years a woman spends raising a chronically ill child and that woman's telomere length (Accelerated telomere shortening in response to life stress, Elissa S. Epel, Elizabeth H. Blackburn, et al.). In addition, women who perceived them to be under greater stress were found to have shorter telomeres. In fact, a person under high stress could expect to see on average a 550 base pair loss in telomere length.  Telomere length correlates linearly with age. This study found that the average person sees a 31-63 base pair reduction in telomere length per a year. Therefore, someone with high stress ages the equivalent of 9-17 years more than their equivalent with low stress! The results of the study are shown below:

Telomere Length v. Stress (Years Caring for Terminally Ill Child)

As the studies mentioned in this article demonstrate, a low-stress lifestyle is important for controlling cellular aging and the chronic illnesses that have been shown to be associated with shortened telomeres: cancer, heart disease. However, all hope is not lost if you are in a situation where stress cannot be controlled. In my next post on this blog I will previewing a 2010 study that found that physical activity may control the shortening effect on telomeres in people with stress.

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