Telomeres — the “caps” on the end of chromosomes that protect the DNA from damage — have been associated with greater longevity. In theory, longer telomeres should allow a cell to divide more times and therefore live longer. However, a new study has suggested that longer telomeres could increase a person’s risk of chronic health conditions. So are longer telomeres key to longevity, or should we be looking to other ways of living longer, healthier lives?
Increasing age is the greatest risk factor for many health conditions. However, some people seem to age better than others, enjoying an active, healthy existence long into old age. So how do they do this? Some credit a healthy lifestyle, others luck, and others genetics.
One theory about aging well lies in our chromosomes or, more specifically, our telomeres — protective lengths of repetitive
Inside every cell in the human body there are 23 pairs of chromosomes. Each chromosome is made up of DNA wound around proteins. That DNA contains
Telomeres are found at the terminal region of each chromosome and do not contain genes. Each time a cell divides, the chromosomes replicate and the telomeres shorten. This allows the cell to divide without losing vital genes. Eventually, the telomeres are too short for the cell to divide again and the cell becomes
Longer telomeres should mean that cells can divide more often before entering senescence or dying, therefore increasing longevity.
So longer telomeres mean longer, healthier lives. Or do they?
Telomeres are maintained by the enzyme
“Studies have demonstrated a correlation between telomere length and biological age. Generally, shorter telomeres are associated with advanced chronological age and increased susceptibility to age-related diseases. Moreover, individuals with certain genetic variations or lifestyle factors that accelerate telomere shortening tend to exhibit a more rapid aging phenotype.”
Telomere length has been likened to a “
In one study, sedentary women were found to have telomeres that indicated they were biologically 8 years older than women of the same chronological age who exercised more.
Other factors that decrease telomere length are stress, depression, and certain gene mutations, such as that which leads to progeria — a rare condition in which children age extremely rapidly and rarely live past their teenage years.
“Recent studies have suggested that telomere length alone may not be a reliable predictor of lifespan or aging. For example, some individuals with shorter telomeres have been found to live longer than those with longer telomeres. Other factors, such as lifestyle, environment, genetics, and stress also play a role in aging and disease.”
– Dr. Joshua Berkowitz, medical director at IV Boost UK
Shorter telomeres may be associated with shorter lifespans and more rapid biological aging, but are longer telomeres therefore associated with longer lifespans and healthier aging? The evidence is not conclusive.
Many lifestyle factors that are associated with better health are also associated with telomere length.
A diet rich in legumes, wholegrain, and fresh fruit and vegetables, such as the Mediterranean diet, is positively associated with telomere length in
Physical activity is advisable for general health, but the evidence for the effect of physical activity on telomere length is not clear-cut — although exercise is thought to be beneficial, the optimal exercise dose is unclear.
One study found that
“While previous research has suggested that longer telomeres may be associated with longevity, most of this research has been done in cells, and it is not yet clear whether longer telomeres in humans are a cause or a consequence of healthy aging.”
— Sebnem Unluisler
Now, a new study has shown that longer telomeres may not be the key to healthy aging. It suggests, instead, that long telomeres allow cells with age-related mutations to live longer, increasing the likelihood of tumors and other chronic health conditions.
The study, which looked at people with a mutation (POT1) that causes longer telomeres, found that, while some showed signs of youthfulness, such as no gray hair in their 70s, those with the mutation had a higher incidence of benign and cancerous tumors, as well as the age-related blood condition
One of the authors, Dr. Mary Armanios, professor of oncology at the Johns Hopkins Kimmel Cancer Center, and professor of genetic medicine, molecular biology and genetics, and pathology at the Johns Hopkins University School of Medicine, suggests an explanation.
According to her, “[c]ells with very long telomeres accumulate mutations and appear to promote tumors and other types of growths that would otherwise be put in check by normal telomere shortening processes.”
Sebnem Unluisler commented that “[t]his study suggests that there may not be a simple relationship between telomere length and aging.”
”While longer telomeres may be associated with increased cancer risk, they may also be associated with decreased risk of other age-related diseases and improved overall health,” she noted.
Telomere length is just one aspect of aging and longevity, and research is investigating many other possible factors.
“The genetic basis of aging is complex, and it is likely that both cellular and whole organism factors contribute to the aging process. While telomeres are one important factor, other genetic and epigenetic factors may also play a role in determining how quickly a person ages.”
– Sebnem Unluisler
Dr. Berkowitz agreed that there are many routes for further study. He suggested that future research might include focus on.
“Identifying genetic and epigenetic factors that contribute to aging and longevity, […] understanding the role of the microbiome in aging and longevity, and […] investigating the role of senescent cells in aging and age-related diseases,” he told us.
Although longer telomeres are associated with longevity in cells, the evidence is not conclusive that they are the key to longer, healthier lives. However, many of the lifestyle factors that reduce the risk of disease also result in longer telomeres.
- get moving — according to
one study, taking around 8,000 steps a day reduced mortality from any cause by 51% compared to taking 4,000 steps.
- eat a healthy diet, such as the Mediterranean diet, with plenty of fresh fruit and vegetable
- maintain a healthy weight — exercise and a healthy diet will help with this
- get a good night’s sleep
- do not smoke, or stop smoking if you are a smoker
- limit your alcohol intake
- get regular health checks
- look after your mental health by socializing and managing stress levels.
Dr. Berkowitz echoed this advice: “While genetics play a role in determining lifespan, environmental and lifestyle factors also significantly influence an individual’s health and longevity. By making healthy choices and adopting a healthy lifestyle, individuals can reduce their risk of age-related diseases and improve their chances of living a long and healthy life.”
Longer telomeres may have some influence on your lifespan, but it is a factor you cannot control, and the evidence for their benefit is not conclusive. However, a healthy diet and lifestyle can increase lifespan and
While research into what is going on in our cells can give us pointers, the tools for healthy aging are largely in our own hands.