If you're a Greek mythology buff, you might be aware of the three blind sisters known as the Fates who share one eye between them and hold the threads of every human life. One would spin the thread of life, the second would dispense it, and the third would cut it off: the longer the thread, the longer the life. This imagery may help you better understand telomeres and aging, as telomeres and DNA strands shorten as you grow and age, and may be one of the keys to living a longer life. Read on for a detailed explanation of what telomeres are, how they function, and why lengthening short telomeres could prolong a healthy life.
What Are Telomeres?
Here's the long and the short of it: telomeres are the caps on the ends of chromosomes that help protect our unique genetic code from damage or rogue influences.
Our DNA strands are made up of chemical base pairs and are bundled together inside the nucleus of each of our cells, bundles that are known as chromosomes. Each of these chromosomes has our genetic information, our genes, and when cell division occurs, these genes are replicated so that every new cell carries these blueprints. At the end of each chromosome are substance strands known as telomeres, which protect the ends of our chromosomes from trying to fuse together. Telomeres guard our chromosomes against any damage.
The problem is that as we age our DNA strands get shorter, losing some genes in the process. Telomeres are there to help prevent gene loss, but as our chromosomes replicate, our telomeres shorten too. The way to build back up these telomere protectors is with an enzyme called telomerase, which can add extra telomere sequences onto the ends of our DNA strands, but most somatic cell types (which are non-reproductive cell types) do not contain telomerase, meaning our telomeres inevitably shorten over time, affecting human health.
Length of Telomeres and Aging: What's the Link?
There is some evidence that telomere shortening contributes to the aging process and disease development in human cells. Though the science is new and more investigation is needed, here are some of the recent studies linking telomere length and the symptoms of aging.
This review of studies from 2011 notes that markers for DNA damage increase with age, just as telomere function decreases. This correlation could be a significant finding, as another smaller study from 2003 showed a link between shortened telomeres and increased rates of death from infectious disease and heart disease, which is the top cause of death worldwide. Another more recent meta-analysis of studies also suggests a connection between shorter telomeres and coronary heart disease.
Not only do shorter telomeres appear to increase the risk of cancer, but these specific cancers have been studied in connection with human telomere length:
One of the characteristics of cancer cells is that they profligate and divide rapidly compared to healthy human cell types. While the division of normal human cells leads to shorter and shorter telomeres, somehow tumor cells are exempt from shortening their telomeres into oblivion, which causes cell death. How?
Researchers assert that it's because the telomerase enzyme that adds length to telomeres is actually increased in 90% of cancers according to this 2016 study published in the journal Genome Medicine. While even our original stem cells have a limited capacity in using the anti-aging telomerase enzyme, cancer stem cells have no such limitations and use it to maintain long telomeres and protect their destructive or mutated genetic material for more extended periods of time.
Because of this telomere research, some cancer treatments now involve targeting the cell biology of cancer cells, hoping to cause telomere dysfunction and cell death.
3. Oxidative Stress
If you've ever gone on a health kick, you've probably been prompted to consume more antioxidants, nutrients that can help fight oxidative stress and the DNA damage done by free radicals in the body. Oxidative stress is linked time and time again with chronic conditions and diseases like diabetes, cardiovascular disease, and various cancers.
Because our telomeres work to protect our DNA too, increased oxidative stress could cause telomeres to shorten, just as shortened telomeres could lead to more damage done by oxidative stress. It's a truly vicious cycle that contributes to human aging and shortens our health spans, and while avoiding environmental poisons like pollution, alcohol, and smoking can help, as can utilizing natural ways to combat inflammation, there is some damage we're not going to be able to avoid.
The damage done to our DNA and the telomeres meant to protect that information leads inevitably to increased biological age and all the symptoms associated with aging cells like age-related diseases and death.
How Do You Lengthen Telomeres?
Since telomere biology appears to be such an important aspect in premature aging, what can you do to help support the role of telomeres in protecting against cellular aging? So far gene therapy meant to lengthen telomeres is inconclusive, however there are ways to help delay the shortening of these vital life threads and maintain the heathy lengths that you still have.
If your telomeres shorten enough, your chromosomes can no longer replicate, which causes the cells they're housed in to undergo cellular senescence. In other words, they die. Enough cell death, and your body reaches such a weakened state that your immune system can no longer protect you from opportunistic infections and diseases, which could ultimately result in your death.
The following advice comes from a 2013 study that analyzed the telomere length of men diagnosed with low-risk prostate cancer. One group was instructed to make certain lifestyle changes (regular exercise, healthy diet, and managing stress), while the control group was not. After 5 years, those who improved their lifestyles had longer telomeres than those who did not, giving researchers a basic understanding of how these three aspects influence telomere length.
1. Regular Exercise
Regularly exercising helps reduce oxidative stress, as evidenced by a 2017 study of thousands of American men and women. This study suggests a connection between high levels of physical activity and significantly longer telomere lengths.
2. Healthy Diet
Everyone knows a healthy diet is a boon to your overall well-being, but researchers have been able to link healthy dieting to telomere length specifically. A 2016 study found that a Mediterranean diet full of antioxidants may help, while an even more recent 2018 study found that longer telomere length could be linked to greater fiber intake.
3. Managing Stress
Cell biologist and Nobel Prize-winner Elizabeth Blackburn in an interview with the New York Times said, "We know that stress is bad for cells. What about alleviating it? We’ve been collaborating on studies looking at the telomerase levels in people who practice meditation."
Stress increases oxidative stress, and study after study has shown that increased stress and cortisol production reduces telomerase activity and increases telomere shortening. Whether it's through meditation, yoga, improved sleep, or talk therapy, anything you can do to alleviate your stress could help protect your DNA.
Telomeres to Live Longer
These structures capping our chromosome ends can protect our DNA from dozens of risk factors for chronic disease and aging. While some diseases like dyskeratosis congenita (a progressive bone marrow failure syndrome) cause rapid telomere shortening, premature aging, and death, those who have enough health to prevent telomeres from shortening should focus on improving their lifestyles, thereby extending their lives.