A wide range of studies has shown that the stress caused by things like untreated depression, social isolation, long-term unemployment, and anxiety attacks can speed-up the aging process by shortening the length of each DNA strand.
Every human cell has 46 chromosomes—23 come from your father and 23 come from your mother. Each chromosome is like a DNA library with two protective caps on the end known as telomeres. As telomeres become shorter, their structural integrity weakens, which causes cells to age faster and die younger. In human cells, telomeres are usually single-stranded DNA that contains several thousand repeats of a simple TTAGGG sequence.
At a certain point of shrinkage, cells lose their ability to divide further. This stage is known as "replicative senescence." Cellular senescence is a necessary mechanism to eliminate worn-out cells, but it also appears to contribute to premature aging and shorter human lifespans.
Telomere length is a marker of both biological and cellular aging. Stressful life experiences in childhood and adulthood have previously been linked to accelerated telomere shortening. Shortened telomeres have been associated with chronic diseases and premature death in previous studies by Dr. Owen Wolkowitz and colleagues at University of California, San Francisco (UCSF).
Longer Telomeres Linked to Longevity
Epigenetics is the study of changes in gene activity that are not caused by changes in the actual DNA sequence. Unlike traditional genetics, which is based on changes to the DNA sequence of the genotype, the changes in gene expression or cellular phenotype of epigenetics have other causes.
The root epi- (Greek: over, outside of, around) indicates chromosome structural changes usually caused by lifestyle choices, as well as, social and environmental stressors. Previous studies in rodents—and in humans—have shown dynamic epigenetic responses to physical stimuli such as stress, diet, or exercise can occur for better or worse within just a few hours.
I have written a plethora of Psychology Today posts about the power of lifestyle choices to improve well-being, reduce disease, and increase longevity. A pilot study released in September 2013 showed for the first time that changes in diet, exercise, stress management, and social support may result in longer telomeres.
Loneliness and Shortened Telomeres
An April 2014 study by scientists at the Vetmeduni Vienna in Austria examined the telomere length of isolated “lonely” African grey parrots compared to parrots with a partner. The researchers found that the telomere lengths of single parrots were shorter than those housed with a companion parrot. African grey parrots are highly social birds, but unfortunately in captivity they are often kept in isolation from other parrots.
Although no human studies have been done on social isolation and telomere length, this new study supports the hypothesis that loneliness can interfere with cellular aging and DNA repair. The findings of the Austrian study are published in the journal PLOS ONE .
Phobic Anxiety and Shortened Telomeres
A July 2012 study from Brigham and Women’s Hospital (BWH) found that chronic phobic anxiety shortened telomere length in middle-aged and older women. The study suggests that untreated chronic phobic anxiety is a possible risk factor for accelerated aging.
For their study, the BWH researchers obtained blood samples from 5,243 women, age 42 to 69 years, who were participants in the Nurses' Health Study. Using the samples, the researchers analyzed telomere lengths, as well as the participants' self-reported level of phobic symptoms.
Having a high level of phobic anxiety was associated with significantly shorter telomere lengths. The difference in telomere lengths for women of the same age who were highly phobic vs. not phobic was equivalent to six years of premature aging.
Untreated Depression and Shortened Telomeres
Untreated depression creates biological changes that accelerate aging and increase the risk of life-threatening diseases. Major depressive disorder (MDD) can shorten the length of telomeres. A team led by Owen Wolkowitz, MD, professor of psychiatry at UC San Francisco (UCSF) has been studying the biological link between chronic depression and an enzyme called telomerase which is linked to shorter telomeres.
The scientists discovered that within the cells of the immune system, activity of telomerase is generally greater in individuals with untreated major depression. Over time, untreated depression can shorten telomeres and make people prone to diseases typically associated with advanced age such as heart disease, diabetes, osteoporosis, and stroke. These findings were presented at the annual meeting of the American Psychiatric Association in San Francisco in May of 2013.
Along the lines of untreated depression and shortened telomeres, a Finnish study from November 2013 found that men who had been unemployed for more than two of the preceding three years were more than twice as likely to have short telomeres compared to men who were continuously employed.
Conclusion: Mindfulness Meditation Can Reduce Stress and Influence Genes
In a groundbreaking discovery, a collaborative team of researchers from Wisconsin, Spain, and France reported in December 2013 the first evidence of specific molecular changes at a genetic level following a period of mindfulness meditation.
The study compared the effects of a single day of intensive mindfulness practice between a group of experienced meditators and a group of untrained control subjects who engaged in quiet non-meditative activities. After an intensive day of mindfulness practice, the meditators showed a dramatic range of genetic and molecular differences.
The study, led by Richard J. Davidson and colleagues, wasn’t designed to distinguish any effects of long-term meditation training from those of a single day of practice. Instead, the key result is that meditators experienced genetic changes following mindfulness practice that were not seen in the non-meditating group after other quiet activities. This outcome provides proof that mindfulness practice can lead to epigenetic alterations of the genome, according to the researchers.