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The promise of longer life grows, but 'eternal youth' remains out of reach
Tuesday, July 06, 1999 By Gary Rotstein, Post-Gazette Staff Writer
First of two parts on how we age.
Researchers are creating longer-living fruit flies in California and longer-living worms in Colorado. In university and pharmaceutical laboratories across America, they're searching for genes connected to aging, testing the long-term benefits of reduced caloric intake, delaying reproduction by small organisms to prolong their life span, studying whether supplements of certain vitamins and hormones prevent or postpone disease.
At the end of a century that has seen a phenomenal expansion of the average American's life span, there are more scientists than ever before absorbed with the secrets of whether our bodies can stay young, virile and healthy and ignore each year's additional birthday candle.
But even as the ranks of those reaching age 100 swell, and some researchers confidently predict that age 150 won't seem astounding in the 21st century, most of those who study aging concur that no one in this millenium can yet lay any more credible claim than Ponce de Leon to finding the fountain of youth.
University of Idaho associate zoology professor Steven Austad, author of the book, "Why We Age," is one of the optimists believing people in the next century will routinely exceed the record old age of 122 reached by Jeanne Calment of France before her death in 1997.
But he and other researchers are leery of the nationwide boom in physicians, clinics and products that already claim to offer "anti-aging" solutions.
"Those of us in the research community have to point out that there's absolutely nothing proven to slow aging in humans, and then if people -- knowing that -- want to use these clinics, it's up to them," Austad said.
"It's a weird time where we're on the verge of legitimate breakthroughs, but there's nothing really available for people that's proven out there," he said. "The difference is there are really good scientists working on the problems now, and you couldn't have said that too long ago."
The U.S. Census Bureau last month released an estimate that 70,000 Americans are 100 or older, compared with just 3,000 in 1960. The number could approach 1 million by the middle of the next century.
The estimates came out shortly after PBS aired a three-hour special, "Stealing Time," tracing the different theories on how and why older adults are living longer, healthier lives today and how future life spans might be extended. The average life span predicted for current newborns in the United States is 76 years, compared with 47 for someone born in 1900.
The fast-growing group of centenarians has been studied for common traits that might explain why they live so long compared to their peers.
In one study in Boston, the biggest similarity was how well the individuals interviewed had all handled stress in their lives, said John Lauerman, a science writer who was co-author of the book "Living to 100" with two medical researchers. Those surveyed who had seen the entire 20th century seemed to make necessary adjustments throughout to changes in society and their personal lives, including loss of loved ones and some disabilities due to aging, rather than seek any tricks to extend their longevity.
"I think the key to a happy and healthy life is to try to work within that system [of normal aging], and centenarians do that extremely well," Lauerman said. "It's a life span that has served people well for many years. I think most people who live to 100 feel like they've lived a long time, they've lived well, and are extremely satisfied."
But normal aging isn't what everyone wants, certainly not those visiting stores and clinics in search of the latest hormone therapy or jar of anti-oxidant vitamins purported to rejuvenate the body.
The American Academy of Anti-Aging Medicine represents the leading proponents of those who believe some answers to longer life are already at hand, and it has grown by leaps and bounds to 7,000 members -- many of them physicians -- since its formation in 1993. Its latest national conference in June attracted 1,250 believers, nearly double the attendance of last year.
"There's huge new interest from the physician population. It's not controversial any more," said Dr. Ronald Klatz, founder and president of the academy, who views the PBS special as evidence that the group's philosophy of extending life is now mainstream. He's not so different from Austad in predicting that "within 50 years we will see life spans routinely of 120 and probably 150 and possibly 200."
Where the academy differs from many researchers is in suggesting that there's no need to wait for all of the laboratory work on age-related cells, genes and enzymes to be completed before offering the youth-obsessed public some hope.
"Ultimately, the big answers will come out of basic sciences, but right now we have the opportunity to make a big impact on people's lives and the quality of life," Klatz said. "There are tremendous inroads through clinical interventions now," such as by hormone replacement therapy, "and by increasing the quality of life you can also increase the quantity."
Many of the academy's members tout some combination of intensive exercise, careful diet, vitamin supplements and hormone therapy as the key to longer, healthier living.
Reversing the aging process is not that simple, counter many research scientists. They argue that healthy exercise and eating clearly help prevent certain diseases, but do nothing to halt the gradual deterioration that is the true sign of aging.
"Nobody in the world can sprint as fast at 50 as they can at 20. That really illustrates what aging is," Austad said. "Slowing down the aging process will do more than simply keep us from getting disease -- it should help us stay at an athletic peak longer."
Vitamins A, C and E are generally agreed to have value in battling what are known as oxygen free radicals, which damage cells and are associated with many age-related diseases. But those anti-oxidants can be derived from a healthy diet rather than relying on large vitamin supplements, some researchers note.
And emphasis on hormone therapy -- such as estrogen replacement and dosages of DHEA, a hormone that normally declines after puberty -- remains controversial despite Klatz's assertions, because some tests on laboratory animals have shown an increased risk of cancer and too little research has been done on humans.
The mass of anti-aging remedies being promoted is a great irritant to some researchers, and government agencies have cautioned companies about how to market them and warned consumers about how much faith to put in them.
"There's a tremendous lunatic fringe in this field," declared Leonard Hayflick, professor of anatomy at the University of California, San Francisco, whose research on the aging of cells dates to the 1950s.
"There's no limit to the ability of people to believe something without evidence," he lamented. "There is absolutely no evidence that there exists a method for intervening with the fundamental processes of biological aging -- period."
Hayflick is an extremist at the opposite end from Klatz, because the professor believes laws of physics will prevent virtually any gain in life span. At age 71 himself, he views any gain as a negative for society anyway.
"Do you want the tyrants of the world to live forever? Or the serial murderers and all of the other undesirables to have the capacity to live forever? I don't think so."
There is, of course, a middle ground on all of this, staked out by those who see more positives than negatives to people living longer, and potential for progress in achieving that goal based on laboratory work thus far.
Much enthusiasm has been generated by collaborative research in the field of cell aging and division at the University of Texas Southwestern Medical Center and Geron Corp., a California biotechnology firm. Cells normally divide throughout much of life and then stop doing so, as a sign of aging, but the research team identified an enzyme, telomerase, that they say enables cells to divide indefinitely.
The problem is that the unusual division of cells late in life is also what happens when people have cancer, and it's unclear as yet whether telomerase can be useful in preventing aging without increasing cancer risks.
Other researchers in various trials, the most prominent of them at UCLA, have been able to extend the life span of rodents by one-third or more by reducing the calories they consume, and it also makes them healthier than counterparts on a more typical diet, or who eat as much as they please. Scientists generally have been optimistic about the research, but they note too little is known about whether it would work for humans, and the population as a whole might find the strict diet hard to swallow.
Part of the problem with life span research is so much of the work is done on simple organisms such as fruit flies and small worms in addition to mice, because they're easy to work with in a laboratory and their life spans are short enough to begin with. The long-term effects of lab-manipulated changes in them are far simpler to measure than say, in monkeys, although a primate's reactions would be much closer to those of humans.
Research through the National Institute on Aging and elsewhere has begun making use of primates, but conclusive results could take decades. Despite the differences between humans and smaller organisms, positive results such as one researcher's ability to manipulate genes of tiny worms to double their life span shouldn't be discounted, say those in the field.
"On the surface, you can't make a direct connection" between the effects on tiny species and humans, but research results can lead analysts in the direction of finding common genes we share with the organisms that could confer longevity, said Frank Bellino, acting associate director of the NIA's biology of aging program.
Despite the increasing attention given the subject of life span, Bellino and others say the more important focus is on people's "health span," or extending the amount of time older adults can enjoy life before being physically or mentally debilitated.
After all, a recent survey by the American Association of Retired Persons found only 27 percent of the adults interviewed hoped to live to 100. That figure would no doubt increase if there was some better guarantee of avoiding cancer, Alzheimer's and other late-life illnesses.
For the physicians who deal day to day with the problems of the elderly -- rather than their peers offering anti-aging remedies to anxious adults in their 40s or 50s -- the health span issue is the one they'd like to see addressed before anyone tries to tack on an extra few decades of Social Security benefits.
Recommending such simple steps as better exercise and nutrition represents the one common ground for anti-aging practitioners and a traditional geriatrician such as Dr. Cynthia Napier Rosenberg of The Western Pennsylvania Hospital.
"There's a camp that thinks there is a normal human life span of about 120 years maximum, and the other group who says, 'Who knows?' " Rosenberg notes. "Those are interesting questions, but the issue for you and me is, if we're 90 and enjoying our meal and taking a nice walk in the evening, that's pretty good."
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