How old are you really? Counting birthdays may be a common tally, but your “age” isn’t determined by time alone. New research increasingly shows the importance of considering chronological age as something very different from biological age—in which the body and its cells, tissues and organs all have separate “clocks” that can tick at different speeds.
In his new book Super Agers: An Evidence-Based Approach to Longevity, Topol delves into the recent surge in public interest in biological aging and the accelerating quest to refine ways to measure it—giving a more precise picture of a person’s longevity prospects and of potential ailments that can be prevented or treated early. Scientific American spoke with Topol about the latest research in biological aging, factors that might speed it up or slow it down and what it can tell us about our health.
If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
[An edited transcript of the interview follows.]
The real beginning of this research started more than a decade ago by geneticist Steven Horvath with his “clock” [test], with which, basically using saliva, you could look at specific genetic markers in a genome and predict a person’s biological age. His clock is really known as an epigenetic clock, or methylation clock. As people age, DNA changes and gets methylated—this is when a methyl group [molecule] attaches to specific nucleotides of DNA. I kind of liken it to the body rusting out. Basically, you’re getting marks at specific parts of the genome that track with aging in humans and every other species of mammal.
Then what’s proliferated in the more than 10 years since has been all these other clocks: protein clocks, RNA clocks, immune system clocks—you name it. Using plasma proteins from a blood sample, we can also clock organs—whether it’s the heart, brain, liver or kidney. So we have seen just enormous advances in these clocks, and they keep getting refined with added features. There’s a race to get the best clocks to predict survival.
The question is: When will doctors actually start using them? The medical community is very hard to change. So it hasn’t happened yet, but I believe it will eventually. Tests are also made available by commercial companies, but they can be very expensive. You can run an epigenetic test in a very simple way for $10 or $20, while some of these companies are charging $200.
Obviously our lifestyle also has a big impact—eating a really healthy diet that’s not proinflammatory and doesn’t have a lot of ultraprocessed foods or red meat. Good sleep health helps reduce inflammation. There’s only one thing that’s been definitively shown to slow the epigenetic aging process, and that’s exercise. I think these clocks ultimately are going to be very good incentives for people to adopt a healthy lifestyle. We can’t get everybody to do all these things that we know help them, but if they get their own data and they see something’s off track, the hope is that they’d [change their lifestyle]. That’s, of course, just one of the ways to prevent diseases. There are also drugs and other treatments.
What environmental factors are also important to consider?
We have all kinds of food deserts in the U.S. We have air pollution and unmitigated accumulation in the air and water of microplastics and nanoplastics, which get into every part of our body and induce inflammation. And we have forever chemicals as well that are pervasive. These all play a factor in lifestyle, health and aging.
Let’s talk more about “inflammaging.” We know some inflammation can be good for the body to fight infections, for instance, but a lot can be bad. How does chronic inflammation potentially accelerate aging?
Inflammation and aging are so tightly intertwined. The immune system is really the driver for good [when it attacks pathogens] and for bad when it promotes too much inflammation in walls of arteries or the brain. That’s heart disease and neurodegenerative disease, respectively. But what’s so exciting is we can dial up or down the immune system now. For example, [there have been] natural, amazing experiments with the shingles vaccines, which reduce dementia and Alzheimer’s disease 20 to 25 percent. So how does that work? Well, [the vaccine] amps up the immune system in people and older adults. That’s going to be the critical thing in using these metrics: zooming in on the immune system and inflammation to keep people’s immune system intact and stop it when it starts to go haywire. That’s the future. In the last chapter of the book, I presented the first cut of my “immunome”—an assay of every virus and pathogen I’ve been exposed to, every antibody I have. But that’s just scratching the surface.
The immune system clock could turn out to be the most useful of all; if I could pick one, that’s the one I would want. But the immune system is very complex. Maybe we don’t have to do a systematic, comprehensive assessment of our immunome [that would include checking antibody titers and] sequencing B cells, T cells and interferons. If we can use just a group of plasma proteins, that would be terrific. That remains to be seen. There’s a human immunome project just getting started to try to compare things such as the proteins with the much more sophisticated and expensive ways to get at the health of an immune system.
We feel really great if we get to age 85. “Super agers” who don’t get one of the big four age-related diseases [type 2 diabetes, cancer, or heart or neurodegenerative disease] say “Well, I did it.” Of course, if you get up to age 98, you’re really doing well. I think we’re going to have a whole lot more super agers. But that’s not going to get around the fact that eventually they’re going to develop some problems—one of the big four or other conditions. It could be you get an infection because your immune system is just too weak. Or it could be you break your hip because your bone density is so low and you wind up with a pulmonary embolus [a clot that blocks blood flow to the lungs].
Eventually you die, and you may have a chronic illness between that point of extended health span and when you die. I don’t want to put a sense out there that super agers won’t see problems in the latter stages of their lives. But the point is, let’s extend the health span—high-quality life without these big age-related diseases—as much as we can before getting into the downturn of a health arc.
Lauren J. Young is an associate editor for health and medicine at Scientific American. She has edited and written stories that tackle a wide range of subjects, including the COVID pandemic, emerging diseases, evolutionary biology and health inequities. Young has nearly a decade of newsroom and science journalism experience. Before joining Scientific American in 2023, she was an associate editor at Popular Science and a digital producer at public radio’s Science Friday. She has appeared as a guest on radio shows, podcasts and stage events. Young has also spoken on panels for the Asian American Journalists Association, American Library Association, NOVA Science Studio and the New York Botanical Garden. Her work has appeared in Scholastic MATH, School Library Journal, IEEE Spectrum, Atlas Obscura and Smithsonian Magazine. Young studied biology at California Polytechnic State University, San Luis Obispo, before pursuing a master’s at New York University’s Science, Health & Environmental Reporting Program.
Source: www.scientificamerican.com