WeeklySA_AdminLONGEVITY: Researchers are studying why we get older, and how to stay healthy as we do…
By Alonso Nichols
For a phenomenon as old as time, aging remains remarkably mysterious. But experts across at United States’ Tufts University are working to change that.
Anti-wrinkle creams, superfoods that keep you young, dietary supplements that promise improved memory, “immortal” cells that can renew themselves forever—in our stores and media, claims about aging abound.
But do you actually understand how your body and mind change as you age? How much of aging is particular to you, and how much can you control? Do you know how you want to age, or what aging well means? Do you know what aging is?
At Tufts’ School of Medicine, they are studying cardiac health in postmenopausal women; at the School of Dental Medicine, they are putting students in special suits to simulate aging; and at the Friedman School of Nutrition Science and Policy, they are teaching future dietitians, scientists, and policymakers about the nutritional needs of older adults.
And the hub of it all is one of the largest research centres in the world that focuses on healthy aging and its relationship to nutrition and physical activity: the Jean Mayer USDA Human Nutrition Research Centre on Aging (HNRCA) at Tufts.
“To me, aging is the most compelling issue in modern biology. It’s surprisingly complex,” said Christopher Wiley, a scientist on the Basic Biology of Aging Team who studies the role of nutrition and metabolism in aging at a cellular level. “There are so many ways of getting at the same problem. There’s always going to be something new to figure out and something new to study.”
It’s an exciting moment in the science of aging—and an important one, said Sarah Booth, director of the HNRCA and senior scientist and leader of the centre’s Vitamin K Team.
“Aging is the new reality,” Booth said. “And most people aren’t even thinking about the implications for society.”
To adjust to this new normal, we must understand what aging really is. An answer is emerging—a deeper, more nuanced one that challenges and often contradicts the popular understanding, that could transform how each of us lives, as well as our whole society.
How to talk about Aging
Why do we still know so little about aging? Humans have always gotten older—yet the term “geroscience,” the study of the mechanisms of aging, didn’t even exist until a decade ago.
Aging research is new, because aging as we know it—large numbers of people spending long periods of time in older age—is new. Life expectancy in the US was only about 62 for men and 64 for women 100 years ago, in 1943. In 2020, persons reaching age 65 had an average life expectancy of an additional 18.5 years (19.8 years for women and 17.0 years for men).
So what is aging, anyway?
Here’s what it isn’t, according to Wiley: conditions such as arthritis, cataracts, heart disease, Alzheimer’s, Parkinson’s.
“We associate these chronic degenerative diseases with aging, because their incidence rates increase exponentially among older people,” Wiley said. “The basic processes that underlie aging can drive chronic degenerative conditions. But chronic degenerative conditions are not aging, per se.”
Another thing that aging is not, at least for the purposes of most research: what happens when we’re younger. We’re technically getting older from the moment we’re born, but that doesn’t become relevant at the HNRCA until we reach a certain age.
“Older adults” is the proper term, Booth emphasised—not “elder,” “elderly,” or “old,” which are vague, negative, and no longer used in the scientific literature.
How old is an older adult? It depends who you ask. A number of federal agencies set it at 65, but that number may date back to the average lifespan of American men in the 1930s, when social security was established in the United States, Booth said. Other federal agencies focus on adults 60 and older, while the American Association of Retired Persons works with those 50 and older.
Sixty-five is also a common cut-off in research on older adults, Booth said—although studies of older women often use menopause, because it’s a distinct, measurable event that changes aging. Studies of sarcopenia, or muscle wasting, often focus on adults in their 80s and 90s, which is the period when that disease tends to develop. “It really depends on the scientific question,” Booth said.
So what is the process of aging, biologically?
Wiley defines it simply: It’s a loss of function over time. It happens to everything. Metal rusts and loses strength. Springs get less springy. The wind-up toy stops working.
More complex objects have more parts to wear down, more functions to be lost, and a much wider range of possible failures. “You could have two cars, same makes, same model, driven by the same person, and two different things will fail on the car,” Wiley said.
The same thing happens to the human body. “There’s damage to your cells happening all the time,” Wiley said. Except the body, with its many interlinked processed, systems, and levels of organisation, is much more complex than a car—and therefore has many more points of potential failure.
When you think about just how intricate and finely tuned the human body is, Wiley suggested, the real mystery isn’t why it fails—it’s why it survives. “The fact that life works is amazing,” Wiley said.
The body does have one advantage: it’s self-repairing. But as we get older, Wiley said, cells are unable to keep up with the repairs. Small failures accumulate.
Different types of cells express damage in different ways. The lenses of our eyes stiffen and cloud. The cartilage in our joints thins and our ligaments shorten, losing flexibility. Blood vessels harden, bones become fragile, and muscle and brain mass decline.
We can replace things—hips, livers, even hearts—but not forever. We’re too complex, and the damage too steady.
If we can’t defeat aging, what can we do?
Figure out how to live longer, is most people’s first thought. But there’s a fundamental limitation to studying how to make human lives longer.
Also, living longer doesn’t address the real problem—and could actually make it worse. “The challenge is that more and more people are living disabled for longer periods of time before life ends, which has huge consequences for society in terms of health care, culture, and ethics,” Booth said.
Lengthening the time in which we can continue to move around, care for ourselves, and participate in social life and activities, is a worthier goal than extending years of suffering, Booth argued.
People tend to use the word “longevity” to refer to both longer life and better health as we age, which is why Booth prefers “lifespan” for chronological age and “healthy aging” for improving biological age.
“Healthspan” has promise as a term for our years free of disability, Booth noted—but it doesn’t cover the increasing numbers of older adults who are losing their health but retaining their abilities through the new field of gerotechnology, which spans smartphone features, ambient systems, robotics, artificial intelligence, and more. “We are continuously moving that threshold of that ability to live independently,” Booth said. “It’s a really exciting time.”
How do we lengthen people’s healthy years?
First, according to Booth and Wiley, we must solve a mystery central to aging: why no two individuals age alike.
“There’s really not much difference between babies, but you see much greater variation in biological aging in older people,” Booth said. “The big challenge is, why do some people have these aging processes that don’t result in chronic disease-related disability, and others do?”
Many drivers of aging are mechanisms that we have in common.
One of these things is diet. The HNRCA is embarking on a major study of how and why certain diets have different effects on individuals’ aging and other biological processes.
Other factors that influence aging are genetics, exercise, environment, stress levels, and even socioeconomic class, to name just a few. But we don’t know how much each contributes—it’s hard to isolate one factor, or even to look at all of them.
So how do we look at everything that ever happens to us across our lifetime, and use it to understand aging?
We do it together, according to Booth. The HNRCA brings together more than 40 scientists working across a wide range of fields to study how exercise and nutrition accelerate or slow down the common biological processes of natural aging. It has research teams focusing on the brain, the heart, the eyes, and bones, along with cancer, obesity, and more.
“We’re looking at the same question through different lenses with different tools, technologies, and perspectives,” Booth said. And slowly but surely, that progress is happening, says Wiley. Researchers are making headway in the question of why two worms with the same genetics have different lifespans, zeroing in on small fluctuations early in life that become large differences later.
“The biggest change I’ve seen in the past 10 years is that we really are finding new, different ways of actually intervening somewhere that could potentially extend the healthy years of life, and prevent people from getting age-related diseases,” Wiley said. Public perception has yet to catch up with the new ways scientists are thinking about and researching aging, Wiley said, but there’s one thing he hopes people understand.
“What aging research is really trying to do is compress the morbidity and make it as small as possible—to alleviate suffering,” Wiley said. “I think that’s a much more humanitarian goal, and I think we’re having a lot of success with those efforts.”
