It is the quest that powers the nation’s sweat-drenched treadmills, that provokes innumerable diets, that seduces many people to visit plastic surgeons. Like latter-day Ponce de Leons, millions of Americans search for fountains of youth–lifestyles, treatments or supplements that will both keep them young and, they at least can hope, extend their natural life spans.
For eons that battle has been fought with marked, if gradual, success. During the Bronze Age of 3000 B.C., life expectancy averaged about 18 years. Some three millennia later, citizens of the Roman Empire averaged 26 years. Regardless of race or gender, the average life span stood at 47.3 for Americans born in 1900; today it has rocketed to 77.2, owing to better sanitation, immunizations and advances in medicine–with the development of antibiotics high on that list.
Now medical science promises–some would say threatens–to greatly outstrip its past achievements. While no human is known to have lived more than 122 years, researchers envision a day in which 150 is not unreachable. The most ambitious microbiologists aren’t satisfied with that; a few have whispered the belief that human cells–the building blocks of our bodies–can be coaxed and kept alive for, oh, maybe 500 years.
The mind boggles. Mick Jagger performing at 60 is one thing. Imagine him performing at 460–for ancient concert-goers whose oldies’ collections would include Chubby Checker, the Partridge Family and Eminem.
Already, manipulation to turn on and off certain genes has extended the life spans of fruit flies, yeast and nematode worms–the typical early fodder of laboratory experimentation.
This research is promising–so much so that phalanxes of academic scientists and a host of private companies are plunging down parallel paths, hoping to unravel secrets that could add humans to the list of biological beneficiaries.
Trailing in hot pursuit are critics who raise questions that, in the age of cloning and other human interventions, already dog the life sciences: Just because we can extend life spans, does that mean we should? Or are we better guided by Ecclesiastes, with the admonition that there is a time to live, a time to die? And if we do proceed to turn research into reality, how will we cope when the laws of unintended consequences create problems we cannot foresee today?
There is no guarantee, for example, that any years we gain would be spent in youth or good health–rather than in senility and dependence. If genetics or drug therapy merely stretches out our existing life span like taffy, how would it feel to be an adolescent for 40 years? (Or to have to parent an adolescent for 40 years?)
Some gerontologists suspicious of life span extension wryly cite the Greek myth of Tithonus, who was married to Eos, goddess of the dawn. Eos, fearful that Tithonus would someday die, asked Zeus to grant him eternal life. She forgot, though, to also ask for eternal youth. So Tithonus grew ever more aged and infirm, a victim of debilitating senescence because Eos hadn’t anticipated the consequences of her wish.
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Much of today’s longevity research essentially treats aging as a disease that needs to be cured.
This is a dicey area for science: Discussions of life-extension ideas such as cryogenics–the freezing of corpses in the hope they can be brought back to life someday–usually include allegations of quackery.
That’s not entirely fair. Current longevity research more closely parallels genetic and pharmaceutical detective work to understand how diseases associated with aging–Alzheimer’s, Parkinson’s, osteoporosis–attack humans.
For now, the known strategy most likely to lengthen life spans is to severely restrict the intake of calories. Rodents fed one-third fewer calories than they routinely would eat can live up to 50 percent longer than they would otherwise. Recent research at Imperial College in London suggests that life spans may begin to lengthen at the instant living creatures–or at least fruit flies–switch to stingy diets.
Most of us aren’t likely to switch to diets that stingy. Which is why scientists are searching aggressively for drugs or genetic therapies that could mimic the effects of caloric restriction. Researchers such as David Sinclair, a Harvard Medical School assistant professor who is emerging as a star in this field, envision a single, anti-aging pill that could thwart a variety of physical problems that occur as people get older.
One promising avenue already has some researchers drinking more red wine. They’re studying a natural chemical called resveratrol, which is found in red wines and which may turn on and off genes that drive aging. That appears to be its effect on yeast and on those pesky fruit flies, which at this rate will soon outlive us all.
Organisms may synthesize resveratrol when they detect that they’re starving or otherwise under stress; the chemical in turn evidently influences certain genes to slow the aging process. What this portends for humans–many of whom presumably would rather drink wine than vastly slash their caloric intake–isn’t yet clear.
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Nor is it clear how society would grapple with a new gerontocracy. For every perceived benefit–more time with our descendants, more opportunities to gain (and maybe even impart) wisdom, there are potential drawbacks. One question is whether we would work more years, or spend those years in retirement. If the latter, imagine Social Security, pension systems and Medicare struggling to cope. A slogan popularized a decade ago by Prudential Securities caught the broader point: “Perhaps the one thing worse than dying is outliving your money.”
And money would be a concern. Extending life spans probably won’t come cheap. Would we devise a system for equality of access to whatever science discovers? Or would the size of one’s bank account determine the length of one’s life? Who could live longer–and who would decide?
Similar issues surfaced during an ugly public policy debate in the 1980s about whether expensive health resources should be rationed–with more care devoted to the young and less to the old. In 1987, ethicist Daniel Callahan authored a controversial book called “Setting Limits” that asked whether further health care should be denied to people who already had lived out a natural life span, perhaps 70-some years.
Callahan’s work loosely echoed a theme attributed–mistakenly, it appears–to former Colorado Gov. Richard Lamm, namely that the elderly have a duty to die and get out of the way. What Lamm did argue, in a publication of the American Society on Aging, was that, “The delivery of expansive medical miracles to the explosively growing number of elderly is creating an unsustainable economic and social burden.”
The mere suggestion of greedy geezers soaking up a disproportionate share of health spending infuriated many older Americans. But imagine the debate if lengthening longevity gradually creates a new generation, the ultra-elderly.
Another question ethicists have raised may seem esoteric to those of us who pound the pavement in running shoes, hoping merely to stay healthy for as long as nature intended: Would extending the human life span–especially via genetic manipulation–change what it means to be human? Is there a point in the lengthening of longevity where we cross a line between maximizing possibilities and re-engineering evolution?
The answer may depend on how scientists portray their discoveries. “If we manipulate genes to lessen the chance of cardiovascular disease, that may lengthen life spans,” says Northwestern University neurobiologist Fred Turek, who studies aging and longevity. “That doesn’t mean we’re trying to trick God or Mother Nature.”
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Turek would direct scientific efforts less to extending the human life span beyond current natural limits than to what he calls “successful aging”–increasing the number of people who stay healthy longer. That might be not just a wise goal, but a popular one. Elderly Americans have made it clear to pollsters that they fear living in a nursing home more than they fear dying of a disease. As former Gov. Lamm framed the issue at the groundbreaking for a Denver adult day care center in 1996, “The U.S. is spending too much money prolonging dying and not enough money helping seniors to enjoy life.”
This notion of making lives richer has a significant precedent: Only a few decades ago, 65-year-olds were viewed as frail and disadvantaged. Now many 65-year-olds are playing three sets of tennis and enjoying the Social Security and Medicare benefits that keep them financially comfortable and physically fit.
Paying more attention to common-sense health issues could lengthen life spans without new genetic or pharmaceutical miracles. One example: American males born in 2000 have a 32.8 percent risk of developing diabetes; the disease can shorten their lives by an average of 11.6 years. For females the risk is 38.5 percent, with lives cut short by an average of 14.3 years. And yet, as the Tribune’s Ronald Kotulak has reported, although this epidemic is reversible, the twin trends of obesity and inactivity eagerly invite diabetes into too many lives.
The day probably will come when we–or our descendants–will have to wrestle with the medical, social and ethical conundrums that a rapidly expanding natural life span would bring.
But while death may be postponed, it’s not negotiable. We may be best off playing the hand each of us has been dealt as best we can: through diet, exercise and regular medical care.
Research into further stretching human longevity is as tantalizing as it is complex. Northwestern’s Turek says that apart from whether our maximum life span changes greatly, more people will live healthy, active lives to age 100 or so as genetic or drug interventions tame diseases and slow the aging process.
The most important issue then, of course, won’t be how long any of us lives. What will matter most then, as now is how each of us chooses to spend whatever limited time we have.
