Telomeres, the “caps” at the end of chromosomes that protect DNA from damage, have been linked to longer life. In theory, longer telomeres should allow a cell to divide more often and therefore live longer. However, a new study suggests that longer telomeres may increase the risk of chronic diseases. So are longer telomeres the key to longevity or should we be looking for other ways to live longer and healthier lives?
What do we really know about how telomere length relates to aging processes?
Increasing age is the biggest risk factor for many health problems. However, some people seem to age better than others, leading active and healthy lives well into old age. How do they get there? Some attribute it to a healthy lifestyle, others to luck, still others to genetics. One of the theories of aging resides in our chromosomes or, more specifically, our telomeres, protective lengths of repetitive deoxyribonucleic acid (DNA) and proteins located at the end of each chromosome. Each cell in the human body contains 23 pairs of chromosomes. Each chromosome is made up of DNA wrapped around proteins. This DNA contains genes inherited instructions for all functions of the cell.
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 senescent or dies.
Shorter telomeres have been associated with increased disease incidence and decreased survival time. Senescent cells no longer divide, but remain active and have been implicated in many age-related diseases, such as osteoarthritis, atherosclerosis and cancer.
Longer telomeres should allow cells to divide more often before going into senescence or dying, thus increasing longevity. Animal studies have shown that telomeres shorten faster in short-lived animals than in long-lived ones.
A study on mice
bred to have very long telomeres showed that they were lean, had low cholesterol and LDL levels, and had better glucose and insulin tolerance. They also lived longer and had a lower incidence of cancer than regular mice.
So longer telomeres equal a longer and healthier life?
Telomeres and biological age
Telomeres are maintained by the enzyme telomerase. This adds to the telomeres, preventing them from shortening as quickly, allowing cells to live longer. A good thing, perhaps, until we learn that cancer cells have increased amounts of telomerase, which allows them to continue dividing.
Studies have actually demonstrated the correlation between telomerase and longevity:
Studies have shown a correlation between telomere length and biological age. In general, shorter telomeres are associated with advanced chronological age and increased susceptibility to age-related diseases. Also, people with certain genetic variations or lifestyle factors that accelerate telomere shortening tend to have a faster aging phenotype.”
Telomere length has been compared to a “biological clock,” with shorter telomeres indicating higher biological age. Several lifestyle factors have been linked to shorter telomeres. One of them is the lack of physical activity.
One study showed that sedentary women’s telomeres indicated they were biologically 8 years older than women of the same chronological age who exercised more.
Smoking increases the risk of many diseases and accelerates telomere shortening. A study showed that telomere shortening was greater in the circulating white blood cells of smokers, increasing the rate of biological aging.
Insufficient sleep can also influence the length of telomeres, even shortening them during childhood, which can affect health.
All of these factors are linked to inflammation, which is associated not only with telomere shortening, but also with a number of diseases that are more common in old age.
Stress, depression and certain genetic mutations are other factors that reduce telomere length.
Maintain telomere length through diet and exercise
Recent studies have suggested that telomere length alone may not be a reliable indicator of lifespan or aging. For example, some people 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”.
Shorter telomeres may be associated with shorter lifespan and faster biological aging, but are longer telomeres associated with longer lifespan and healthier aging? The evidence is inconclusive.
Many lifestyle factors that are associated with better health are also associated with telomere length.
A diet rich in legumes, whole grains, and fresh fruits and vegetables, such as the Mediterranean diet, is positively associated with telomere length in several studies. The positive effects of the Mediterranean diet on telomeres could be due to its antioxidant and anti-inflammatory properties.
Physical activity is advised for general health, but the evidence for the effect of physical activity on telomere length is unclear although exercise is thought to be beneficial, the optimal dose of exercise is unclear.
One study showed that moderate exercise helps maintain telomere length, but the benefits diminish with excessive exercise; others have found an effect only in people doing extreme exercise, such as ultra-marathon runners.
Other studies have shown that getting enough sleep, never having smoked tobacco, and avoiding stress can help preserve telomere length.
Challenging myths about telomeres
Although previous research has suggested that longer telomeres may be associated with longevity, most of this research has been done on cells, and it’s not yet clear if longer telomeres in humans are a factor. cause or consequence of healthy aging.
Now, a new study shows that lengthening telomeres may not be the key to healthy aging. Rather, she suggests that long telomeres allow cells with age-related mutations to live longer, increasing the likelihood of tumors and other chronic health problems.
The study, which looked at people with a mutation (POT1) that causes telomere elongation, found that while some showed signs of youth, such as no gray hair at age 70, people with the mutation had a higher incidence of benign and cancerous tumors, as well as age-related clonal hematopoiesis, which increases the risk of several cancers, than people without the mutation.
Cells with very long telomeres accumulate mutations and appear to promote tumors and other types of growth that would otherwise be controlled by normal telomere shortening processes. There may not be a simple relationship between telomere length and aging. While longer telomeres may be associated with an increased risk of cancer, they may also be associated with a decreased risk of other age-related diseases and improved overall health.
How to Maximize Your Healthy Life Years
Although longer telomeres are associated with cell longevity, they are not proven to be the key to a longer and healthier life. However, many lifestyle factors that reduce the risk of disease also lead to longer telomeres.
The following measures promote healthy aging:
moving, taking around 8,000 steps a day reduces all-cause mortality by 51% compared to 4,000 steps.
eating a healthy diet, such as the Mediterranean diet, consuming plenty of fresh fruits and vegetables
maintaining a healthy weight, exercise and a healthy diet will help
Sleep well at night
do not smoke, or quit smoking if you are a smoker
limit alcohol consumption
get checked regularly by a doctor
take care of your mental health by socializing and managing your stress.
While genetics plays 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’s something you can’t control, and the evidence for their benefit is inconclusive. However, a healthy diet and lifestyle can increase lifespan and reduce the likelihood of disease, even in people with a genetic predisposition. While research into what happens in our cells can give us some clues, the tools for healthy aging are largely in our hands.