Companies claim they can now easily calculate your biological age. Should you take them up on it?
From the beginning of time, humankind has searched for the secret to a long life. Now science may have found an answer, in the form of molecular augury. The pattern of chemical chains that attach to the DNA in your cells—on-off switches known as epigenetic markers—can reveal how swiftly you are aging, and perhaps even how much longer you will live. While genetic testing might tell you where you came from, epigenetics promises a glimpse into the future. Now, a handful of companies are offering commercial blood or saliva tests based on the science of epigenetics—a chance to find out how old you truly are.
DNA itself is fixed; the genes you’ve inherited will forever make you more or less prone to certain conditions. But your epigenetic patterns change based on what you eat, how much you sleep or exercise, and what substances you are exposed to—and ultimately influence your risk of developing chronic conditions such as heart disease or diabetes. They do so by altering gene activity, like a complex set of controls that turn genes up or down, on or off.
Epigenetics plays a role throughout life, from embryo development to aging, and some epigenetic changes accumulate as the years pass in a way that literally inscribes your age upon your body. That process is influenced by your environment and the things you do or don’t do. If you adopt a new exercise regimen or are exposed to pollutants, your epigenetic patterns may change for the better or worse.
In 2011, after analyzing hundreds of epigenetic markers, Steve Horvarth developed the first epigenetic “clock,” a new way to calibrate aging. It measures specific epigenetic patterns that are linked to aging and disease, and compares that result against what would normally be expected for someone of your age. You may look or feel younger than expected, but this clock puts a number on it and tells you whether you really are aging more slowly than most other people.
That number, what’s sometimes called your biological age, might be older or younger than the years you count on each birthday. Fifty can be the new 40, or 50 can be more like 60.
Horvath, a biostatistician at the University of California Los Angeles, wasn’t trying to create a scientific oracle. A test of cellular aging, he reasoned, would be a powerful tool for researchers trying to find ways to prolong life and health. He created the test by focusing on methylation and demethylation, processes that grow or shrink those chemical chains and thereby control the action of genes. His clock accurately predicted biological age when tested in groups of hundreds of people, giving researchers an efficient way to look for the longevity benefits of drugs or lifestyle changes.
At first, he had trouble publishing his results. It seemed too good to be true that a simple blood test could accurately predict lifespan, says Horvath. But other studies backed up his findings. He has refined the test over the years, and says his lab’s newest test, dubbed GrimAge for the Grim Reaper, is the most accurate yet. (He developed GrimAge for for research, although some version of it could become publicly available in the future.)
The science of an epigenetic clock is now well-established. (There are other clocks in addition to Horvath’s.) The commercial tests to predict your biological age are based on this science—but these proprietary products aren’t independently evaluated. For example, they might not be equally accurate for all ethnic or racial groups.
Still, they can give you some interesting information. Spit into a tube or prick your finger to take a few drops of blood, and send the samples off along with $299 or $500 depending on the test. If you smoke or if you are obese, your epigenetic markers are likely to be biologically older. If you are fit and have a healthy diet, you may detect the benefits.
What’s enticing about this is that if you then make efforts to reduce your biological age by changing your habits, the test might be able to give you a reality check, and tell you whether you are succeeding. Just be aware that tests from different companies will measure different sets of patterns, and the results may not match.
Epigenetic tests don’t need to be approved by the Food and Drug Administration, and company disclaimers state that they don’t screen for or assess disease risk. But already, some life insurance companies have begun using the tests, along with the usual physical exams and family history, to predict your lifespan.
Generally, though, these tests aren’t fortune tellers. You won’t learn exactly how long you have left to live. For one thing, random events—a serious infection, a car accident—play a huge role in lifespan. For another, the test was designed to apply to a population, rather than an individual. It’s one thing to say that a group of people who share a similar pattern of methylation changes will, on balance, live longer. It’s quite another to accurately forecast one specific individual’s lifespan. “It’s not the case we could nail down the date of death of an individual within plus or minus one year,” Horvath says.
Nonetheless, Horvath took his own test when he was 51, to see what it would tell him about how fast he is aging. His biological age was 48.9. His identical twin took the test, and interestingly, his result was exactly the same: 48.9.
That doesn’t exactly mean Horvath will live precisely two years longer than expected. It’s a kind of shorthand, a simple way to convey whether you’re aging more quickly or slowly than the average person.
Morgan Levine, a gerontologist and biostatistician at Yale University, created DNAm PhenoAge when she previously worked in Horvath’s lab. Her test was designed to reflect the risk of major diseases as well as overall lifespan. Beginning in January, her newest epigenetic clock will be sold as a commercial test beginning in January for $500 from the company Elysium Health, where she is head of bioinformatics. It measures patterns at 150,000 DNA methylation sites, which she says enhances its predictive value.
Levine views the test as a tool for personalized prevention, enabling people to see if their healthy lifestyle changes cause their epigenetic age to decline, making them biologically younger. “This is much more reflective of lifestyle and behavior” than a genetic test, says Levine. “People have much more power over this number.”
Commercial epigenetic testing is in its infancy, so consumers should be wary if companies make claims about a specific disease risk or offer to precisely predict lifespan—or use the results to market other products, says Robert Green, a medical geneticist at Brigham and Women’s Hospital in Boston who has studied direct-to-consumer genetic testing. “They have to understand that there’s a difference between something that is provided by a consumer-facing company and something that is recommended with the full force of medical science behind it,” says Green, cofounder of Genome Medical, which provides an online consultation service for people who undergo genetic testing.
If you learn from an epigenetic test that you should improve your diet, lose weight, stop smoking, exercise more, and get more sleep—well, that’s advice you knew before shelling out a few hundred bucks. Still, sometimes a test result—genetic or epigenetic—may be what motivates you to actually change your habits, Green says.
At 34, Levine is conducting her own personal experiment. She took her test last year; it showed her biological age to be 2.5 years younger than her chronological age. Previously a vegetarian, runner, and equestrian, she has now gone vegan and switched her workouts to high-intensity training, which has been linked to anti-aging changes in muscle. She plans to re-test monthly to see if her new regimen slows her biological aging.
Larry Jia, founder and CEO of Zymo Research and Epimorphy, has been selling an epigenetic test that is a modified version of Horvath’s clock to researchers and consumers since 2017. He also took the test himself—and discovered that he is biologically a half-year older than his chronological age, which is 61. He began prioritizing sleep and cutting back on his hours to reduce his work stress, but the number didn’t budge—maybe, he says, because he can’t eliminate the stress of running a company. “Sometimes there are things you can’t control,” he says.
After conducting thousands of tests for customers, he observes some patterns. The rate of aging seems to accelerate in people with a higher body mass index and in current smokers—as well as in people who engage in excessive and intense exercise or who have stressful jobs, he says. But he hasn’t seen that either a meat-heavy or mostly plant-based diet makes a significant difference.
Epigenetic testing may seem as harmless as tapping into a biological horoscope, but it does raise some darker questions. Bioethicist Charles Dupras and his colleagues at McGill University in Montreal examined genetic anti-discrimination laws and found most would not apply to epigenetics. That means people may not be protected from misuse of their profile, such as might happen if employers wanted to use disease risk or other markers in hiring decisions. Privacy policies might not treat epigenetics as sensitive personal data, he says: “It’s another layer of information about the lives of consumers that should be safeguarded.”
For now, our ability to turn back aging is somewhat limited to the familiar advice we already know so well: eat well, exercise, don’t smoke. But researchers are already using the epigenetic clock to test an anti-aging cocktail and to look for an anti-aging diet. If a wellspring of youth exists, epigenetic tests may be the ultimate divining rod.
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