All About Telomeres: What They Are, How They Relate to Aging, and How to Protect Them
Telomeres are considered a proxy for biological aging, as shorter telomere length is linked to accelerated aging and early onset of disease. Research has shown that people with shorter telomeres have both shorter lifespans and an increased risk of chronic diseases.
Due to this well-studied association, researchers worldwide are searching for ways to limit telomere shortening or, even better, to lengthen them. In this article, learn more about what telomeres are, what factors cause them to shorten, and how to prolong or protect your telomeres.
What Are Telomeres?
Telomeres play a crucial role in the aging process, as they protect our cells and DNA from damage. Telomeres are “caps” of repetitive DNA molecules at the tips of our chromosomes, like the plastic casing protecting the tip of a shoelace. Similar to how these plastic casings protect the shoelace from fraying, telomeres protect the chromosome from damage, dysfunction, and premature aging.
These protective endcaps are also necessary to ensure DNA gets copied correctly during cell division, preventing chromosomes from sticking to each other and messing up the even distribution of DNA between the resulting cells. During normal cell division, the telomeres get shorter with each DNA replication, ensuring that critical genetic information within the chromosome doesn’t get snipped off with it. Essentially, the telomeres get shorter with each cell division to save the rest of the DNA in the chromosome carrying the instructions for life.
However, when a cell’s telomere gets too whittled down, the cell can no longer replicate and is considered senescent. Cellular senescence is another marker of aging, which occurs when cells stop dividing, lose function, and trigger a cascade of inflammatory compounds that accelerate aging.
A few decades ago, the protein that adds new telomere DNA, called telomerase, was discovered. During DNA replication in egg and sperm cells, telomerase continually adds more of the repeating sequence to the end of the DNA, allowing for telomeres in these cells to remain intact. However, in somatic cells — meaning, any cells other than sex cells — telomerase activity is low or non-existent, which causes the eventual shortening of telomeres and senescence of cells.
Telomeres can be imagined as the plastic casing protecting the tip of a shoelace, as they protect the ends of chromosomes from damage.
What Causes Telomere Shortening?
In addition to aging, several lifestyle factors accelerate the rate of telomere shortening, including:
- Sedentary lifestyle
- An unhealthy diet with low fiber and antioxidant consumption
- Chronic stress
- Exposure to air pollution
- Excessive alcohol consumption
These lifestyle factors cause oxidative stress, leading to an accumulation of free radicals and reactive oxygen species in the body. These inflammatory compounds are unstable and can damage cells and DNA, leading to shortened telomeres.
Can You Lengthen Your Telomeres?
Recent research has indicated that, yes, it is possible to lengthen telomeres and protect them from accelerated shortening. Many of the previously mentioned diet and lifestyle factors play a role in lengthening or protecting telomere length.
In an October 2018 pilot study published in Lancet Oncology, two groups of men had their telomere lengths measured at baseline and five years later. One group of men made comprehensive lifestyle changes involving diet, activity, stress management, and social support, while the other group made no changes.
The lifestyle modification group experienced significantly increased telomere length, while the control group saw an expected decrease after five years. The results from this study indicate that modest lifestyle changes are enough to not only prevent the typical age-related decline in telomere length but also to increase it.
Exercise is a crucial component of protecting your telomeres. In a study published in PLoS One in November 2011, people with stable heart disease who had the lowest levels of physical fitness were two times more likely to be in the shortest telomere length category, compared to those with high levels of physical fitness.
The link between physical activity and telomere length is especially pronounced in older adults, providing another reason to maintain an exercise routine with age. The mechanism behind this involves the ability of moderate exercise to reduce oxidative stress and inflammation and promote healthy weight maintenance.
Certain dietary factors are involved in the protection of telomere length. A diet high in antioxidants, fiber, vitamin D, and omega-3 fatty acids is linked to a slower telomere shortening rate. Antioxidant-rich foods include berries, green leafy vegetables, dark chocolate, red grapes, and herbs and spices like turmeric, rosemary, and oregano.
In a study published in JAMA in January 2010, researchers found an inverse relationship between blood levels of omega-3 fats (specifically, EPA and DHA) and the rate of leukocyte (a type of white blood cell) telomere shortening. Older adults who consumed the highest amount of these healthy fats had the slowest rate of telomere shortening. Similar to exercise, omega-3 fats also reduce levels of oxidative stress and inflammation in the body.
Adequate vitamin D status is also associated with telomere protection. In a randomized controlled trial published in November 2020, adults with mild cognitive impairment who supplemented with vitamin D had significantly longer telomeres after 12 months compared to those taking a placebo.
Researchers have looked at the effects of NAD+ levels on telomere length. NAD+ (nicotinamide adenine dinucleotide) is a crucial coenzyme needed by every cell in the body; however, its levels naturally decline with age. Very low levels of NAD+ are linked to premature aging and chronic disease development. Fortunately, there is an effective way to boost NAD+ levels — with its precursor, NMN (nicotinamide mononucleotide).
A group of proteins called sirtuins are reliant on NAD+ to function correctly. Sirtuins — the so-called “longevity genes” — are involved in repairing DNA and the power generators of cells (mitochondria) as well as reducing cellular senescence to slow down the aging process. Research has found that increasing sirtuin activity stabilizes telomere length.
Essentially, you can use NMN to boost the amount of NAD+ in cells to upregulate sirtuin levels and activity to protect the telomeres.
Recent Research: Telomerase Activators
Researchers have attempted to mimic the telomere lengthening seen with diet and lifestyle changes using various compounds.
A study published in Rejuvenation Research in December 2016 looked at the effects of a natural telomerase activator called TA-65, which is extracted from the Chinese herb Astragalus. Adults who were randomized to take TA-65 for one year experienced significantly increased telomere length compared to those in the placebo group.
Another study, published in Molecular Medicine Reports in October 2019, tested the effects of eight supposed telomerase activators on human cells. Out of the compounds analyzed, Centella asiatica extract (an herb used in traditional Chinese medicine) exhibited the strongest telomerase-boosting activity, even more than TA-65.
However, telomerase activators can cost you a pretty penny — the recommended maximum dose of TA-65 will set you back almost $5,000 per year — and not all supplements are well-researched before being put on the market. As these supplements do sound pretty miraculous — after all, who wouldn’t want to simply pop a pill and watch their biological aging clock tick in reverse? — many companies are jumping on this anti-aging bandwagon before adequate human trials have been performed. Additionally, these compounds can be controversial among the scientific community, as artificially adding telomerase may cause tumor growth.
While the results from these two studies suggest that lengthening your telomeres may soon be easier to do than previously thought, more research in humans is needed. For now, a safer (and cheaper) way to protect your telomeres is by maintaining the positive and healthy lifestyle habits mentioned in this article.
- Telomere length is a proxy for biological aging; shorter telomeres are linked to accelerated aging and chronic disease development.
- Telomere shortening is caused by factors that increase oxidative stress and inflammation, including obesity, smoking, poor diet, and toxin exposure.
- Telomere lengthening is possible with a diet full of antioxidants, vitamin D, and omega-3 fats, moderate and habitual exercise, and boosting NAD+ levels with NMN.