You may have heard of at-home DNA testing and perhaps sent a cheek swab or saliva sample in the mail to learn more about your ancestry or disease risk. Today, many companies offer over-the-counter tests to measure your telomeres and give you insight into how your body is aging.
What are telomeres?
Telomeres are combinations of DNA and proteins at the end of chromosomes. Like the plastic tip at the end of a shoelace, telomeres prevent DNA from “fraying” or losing genetic material. Your telomeres shorten as you age.
“Telomeres are the main biomarker of aging,” says Juan Luis Sánchez González PhD, professor of nursing and physiotherapy at the University of Salamanca in Spain. “They are considered the clock or timer of the cell because they mark the number of cell divisions until the cell dies.”
Some research has linked shorter telomere length to the risk of diabetes, cardiovascular disease and a shorter lifespan. Research is also focusing on changing telomere length as a way to prevent the risk of age-specific diseases and limit the impact of aging.
The impact of telomere length and cognitive performance or dementia risk is less clear.
In a 2022 study, González compared the telomere length of physically active women in their seventies with inactive women in the same age group and found no relationship between telomere length and cognitive performance. Separate research was found to be shorter and longer telomere length is associated with an increased risk of Alzheimer’s disease. One researcher noted the link was “inconsistent.”
“This is a new field,” says Sue Rutherford Siegel Ph.D., a genetic researcher and professor in the Biomarker Core Lab at Penn State. “We are still trying to research and identify all the ramifications of telomere shortening at this time.”
Does the telomere test work?
Some companies that offer at-home tests promise that your DNA will reveal your true biological age and provide insight into the health of your cells. In fact, the results obtained through the telomere test may not be of any value.
“It’s not like the people who have it [a certain] The measurement of telomere length in health is good because there is a large range [in normal telomere length]”, says Siegel. “Telomeres naturally shorten with age…it’s just a natural aging process, but even among 60-year-olds, you’ll find a lot of difference between the long and the short. [telomeres].”
Not only is there no standard for what constitutes “healthy” telomere length according to age, there are also many different ways to evaluate telomere length and often significant variation in results. Research shows that one common test, the quantitative polymerase chain reaction or qPCR test, has up to 20% variation in results and testing on different days can lead to different results.
“Some of it is measurement error but some of it is [changes to telomere length] it can be a true biological regulation [or] period of shortening and compensatory period of lengthening,” said Elissa Epel PhD, co-director of the Aging, Metabolism and Emotion Center at the University of California. “Having short telomeres is only a risk factor for health [but] only slightly increases the risk for disease. So many other factors are at your risk [like] your health behaviors and genetics.”
Due to these challenges, Epel does not believe that it is necessary to invest in a home telomere test, adding, “If there is someone dedicated to measuring telomere length, before, during and after a big lifestyle change, it could be interesting. But for me [testing] not a priority.”
How to preserve telomere length
You may not need to hand over your credit card information to study telomere length, but it is important to prioritize healthy habits that can preserve or increase telomere length.
Eating a diet full of nuts, seeds, fruit, and coffee (and skipping sugary drinks, red and processed meat) can help maintain telomere length; exercise, optimal sleep and cessation (or not smoking) are also linked to less telomere shortening-but Siegel notes that this is a characteristic of a healthy and beneficial lifestyle regardless of the impact on telomeres.
Despite the overwhelming evidence, even researchers admit that further studies are needed to understand the relationship between telomere length and healthy aging.
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