Telomeres: The Cellular Material That Determines How We Age
DNA is a fascinating thing.
The helix-shaped material that encodes the instructions for how each of us grows, develops and reproduces also holds answers to some of humankind’s oldest questions—including why we age.
A key to understanding the question of aging can be found in telomeres—tiny bits of genetic material on the ends of our chromosomes. There is a correlation between aging and telomere length: the shorter our telomeres, the clearer our signs of aging tend to be.
Thus, our DNA actually carries with it biomarkers of our cellular age, or clear and measurable signs that our bodies know when they’re getting older. Cellular age may translate into organism-level signs of aging—like the development of wrinkles and grey hairs—and also the slow erosion of our vitality.
Below, we take a broad view of what science currently understands about telomeres: how they function, why they are important to our understanding of the aging process, and what each of us can do to raise our energy and vitality levels over time so we can age as healthily as possible.
What Telomeres Do and Why They Shrink
Each of our cells contains chromosomes, which are the X-shaped molecules of DNA that instruct cells how to divide and replicate themselves. At the end of each chromosome molecule is a telomere, a sequence of non-coding DNA proteins that protect the chromosome in the same way eyelets keep our shoestrings from fraying.
Over the course of our lives, many of our cells naturally divide so our bodies can grow, repair wounds and replace cells that have died. During cell division, our chromosomes make copies of themselves so the genetic material they contain can be passed onto the new cell. But “DNA replication is a partially incomplete process,” write biologists Sophie Reichert and Antoine Stier, and some piece of our telomeres are lost during every instance of cell division.
Some cells—like sperm cells and stem cells—have a mechanism in place to rebuild lost telomeric material. An enzyme called telomerase builds back some of the DNA material that was lost during replication so that our chromosomes maintain their protective end caps.
But there is only so much telomerase to go around. “[A]s cells divide repeatedly, there is not enough telomerase, so the telomeres grow shorter and the cells age,” says the team at The University of Utah’s Genetic Science Learning Center.
A Cellular-Level Understanding of Aging
When our telomeres begin to shrink, our cells enter a permanent state of arrested growth known as senescence. At that point, those cells stop dividing and replicating. With this in mind, it seems cellular aging is natural because our cells are created with a limited capacity to replicate. In fact, as Arizona State University researcher Zane Bartlett writes, biologists have for more than 50 years worked under a model that suggests cells can replicate no more than about 60 times, something known as The Hayflick Limit.
The good news? Senescent cells are still functional and metabolically active. As researchers Francis Rodier and Judith Campisi point out, cellular senescence helps prevent the spread of potentially cancerous cells. It also, however, appears to contribute to inflammation, which accelerates the aging process. “The challenge now is to understand the senescence response well enough to harness its benefits while suppressing its drawbacks,” they write.
While there is still much we have to learn about cellular aging, a few things are clear at this point:
- There is a relationship between the cessation of cell division and aging.
- Telomeres indicate how close our cells, tissues and bodies are to this state of senescence.
- Longer telomeres are strong predictors of human longevity and better health.
So, Do We Just Need Big Doses of Telomerase to Stop Aging?
As Dr. Elizabeth Blackburn, co-recipient of the 2009 Nobel Prize for Physiology or Medicine for her work with telomeres, told the crowd at TED2017: “[N]udging up telomerase does decrease the risks of some diseases, but it also increases the risks of certain and rather nasty cancers. So even if you could buy that Costco-sized bottle of telomerase, and there are many websites marketing such dubious products, the problem is you could nudge up your risks of cancers. And we don't want that.”
That said, certain nutrients such as vitamins C, D, E, and B, carotenoids, lutein and lycopene have been associated with longer telomeres. These are the nutrients we put in our VitaYears™ supplements.
The Link Between Telomere Length and Stress
The big breakthrough in telomere science came when researchers understood how much influence each of us has over the lengths of our own telomeres.
Dr. Blackburn described her “eureka!” moment in her TED Talk. It came when fellow UCSF researcher Dr. Elissa Epel asked whether chronic stress affects telomere length. The hypothesis certainly makes sense, Dr. Blackburn figured. People whose lives are particularly stressful show earlier visible signs of aging. So, Drs. Blackburn and Epel began to look into caregiving mothers whose children had chronic conditions—a group that, Dr. Epel knew from her own research, experienced massive amounts of persistent stress.
Sure enough, the data showed that these caregiving mothers had shorter telomeres and lower telomerase.
Subsequent research from Dr. Epel and others has shown that other sources of chronic stress—like bullying or enduring an abusive relationship—also correlate with shorter telomeres.
What’s more, Dr. Epel’s research has found that pregnant women who experience active stress can pass that stress onto their children in the womb; these children are then born with shorter telomeres:
This means that telomere length is affected by more than just how long our DNA says it should be (i.e. genetic factors). Telomere length is also determined by external factors, also known as epigenetic factors. Unlike our DNA, we have some control over these epigenetic factors.
In essence, we have some control over how quickly cellular aging takes place within our bodies and, in turn, how quickly our own bodies age.
What Other Factors Affect Telomere Length?
The scientific community has since identified several other factors that appear to shorten our telomeres.
- Researchers at the Montreal Heart Institute observed a connection between shorter telomeres and psychological risk factors for cardiovascular disease, including high levels of defensiveness, depressive symptoms, hostility and anxiety.
- Reichert and Stier found that cellular-level oxidative stress from aerobic metabolism and ATP production (natural processes our bodies use to turn fuel into energy) is especially damaging to telomeres.
- Researchers at Harvard University found that five lifestyle factors raise a person’s risk for shorter telomeres. These are smoking, having an unhealthy body weight, lack of exercise, excessive alcohol consumption and an unhealthy diet.
That last point is especially encouraging because these lifestyle factors all speak to changes that any of us can make to promote longer telomeres.
Certainly, managing psychological factors such as depression and anxiety are important, and there is much we still have to say on the connection between oxidative stress and aging, but lifestyle choices represent the biggest low-risk/high-reward epigenetic pathways affecting telomere length.
Starting today, any of us can do the following:
- Commit once and for all to quitting smoking
- Take steps toward achieving and maintaining a healthy body weight
- Start folding exercise into our daily routines
- Cut back on our drinking
- Look for ways to make our diets a little more healthy
A New Paradigm of Healthy Aging
What does all of this telomere research mean for you?
For one thing, it suggests that each of us has the very real ability to hack the aging process. By taking steps to influence our telomere length through making healthy lifestyle choices and bolstering the abilities of our cells to practice molecular self-defense through things like anti-aging supplements, we can increase the number of years we experience life as our high-performing, high-achieving selves.
This is what is known as a healthspan, or the duration of a human life in which we are free of chronic illness, our vitality remains intact and we feel healthy.
Telomere science attracts so much attention these days because it points to a world in which we don’t just live longer, but extend the number of healthy, fulfilling years in our own lives.