When we are old: research on animals is suggesting ways to delay senescence in human beings by twenty years or more

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OVER THE PAST thirty years, research on aging has raised the serious possibility that life expectancy might someday be extended by as much as one fourth. Many different lines of research–on diet, metabolism, and the immune system, among other things–are being pursued. One of the most promising of these originated with Denham Harman, professor of medicine and biochemistry at the University of Nebraska, who proposed, in 1954, that the highly reactive molecular fragments known as “free radicals,” which are especially damaging to biological microstructures, might to some extent be counteracted by the increased consumption of antioxidants. These chemical compounds, of which vitamin E is the best known, occur naturally in some foods and are added as preservatives to others–in most countries in tiny and strictly regulated proportions.

Harman and many others are of the opinion that, just as small amounts of antioxidants preserve foods, in larger amounts the compounds might preserve human tissue. Many antioxidants have since been tested for such an effect on laboratory animals, and the increased longevity observed was equivalent, in Harman’s reckoning, to an extension of the average human life expectancy from seventy-three to ninety-five years.

If antioxidants can be ingested safely by human beings, the result is not expected to be an extra decade or two of zombie-like existence, in which people would be alive only in the purely technical sense (or alive enough, shall we say, to avoid becoming transplant donors). Not at all. What the researchers hope for is a prolonging of life such as would be achieved if the seven ages of man were marked off on a length of rubber and the rubber were stretched. A seventy-year-old would have the address to life of a sixty-year-old, and an eighty-year-old that of a seventy-year-old.

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How successful any treatment to prolong life might be is unclear. Growing old is a bad thing quite apart from the decline of bodily faculties and energies that it entails. Even if the process of senescence could be arrested temporarily, we would still suffer from the passage of years. Consider, for example, the likely consequences of extending a woman’s reproductive life to the age of sixty, or beyond. The older a woman is at the age of reproduction, the longer her finite endowment of egg cells will have been exposed to influences that are inimical to it. Thus, even though a woman of sixty might be as physically fit as a woman of thirty, the likelihood of a chromosomal aberration, such as that which causes Down’s syndrome, would have increased with her age. The etiology of cancer is a similar example. Researchers believe that a malignant tumor can start with the mutation of a chromosome following the body’s exposure to ionizing radiation, a toxic chemical, or some other mutagen. Thus, the longer one lives, the longer one has to cross the path of such hazards, and the greater one’s chances of contracting cancer.

Because it is not easy to see a remedy for these side effects of old age, I fear that the incorporation of antioxidants into our diet will have a more modest result than proponents of the theory expect. But there are people who say that such research ought not to proceed at all. Their opposition compels us to ask, Is the extension of the life-span a possibility that we should welcome or a temptation that we should resist?

THE CASE AGAINST efforts to increase longevity takes several forms. It is said, for example, that the prolonging of life runs counter to biblical teaching. Yet “threescore years and ten” (Psalms 90:10) has no authority other than the opinion of a psalmist. In fact, the phrase is something of a cliche in the Bible, standing for quite a number but less than a hundred. Thus we are told that there were threescore and ten palm trees in Elim (Numbers 33:9); that when the house of Jacob entered Egypt, it comprised threescore and ten persons (Deuteronomy 10:22); that Jerubbaal had threescore and ten sons (Judges 9:2). It might be more in accord with the spirit of the Bible if the human life-span were construed to be that which, for better or worse, human beings cause it to be.

People also say that extending life is a crime against nature. I consider this a despondent view, which rests on an implicit nostalgia for the supposedly healthy, happy, exuberant, and yea-saying savages that Jean-Jacques Rousseau spoke for–creatures whose life expectancy probably did not exceed twenty-five or thirty years. This attitude echoes the literary propaganda of the Romantic revival, and it is surely wider of the mark than Thomas Hobbes’s assertion that the life of man in a state of nature is “solitary, poor, nasty, brutish, and short.”

Human life has always been what human beings have made of it, and in many ways we have improved on nature. It cannot be too strongly emphasized that all advances in medicine increase life expectancy; their efficacy is measured by the degree to which they do so. I am referring not only to insulin, penicillin, and the other spectacular innovations of medical history but also to aspirin (which lowers fever and reduces inflammation, besides relieving pain), adhesive bandages, and washing one’s hands before eating. These, too, have contributed years to our life-span.

The whole philosophy of the prevention of disease–and where prevention fails, the cure–represents a deep and long-standing moral commitment to life, and the research in question here is its logical development. Thus, one could argue that, our commitment to the preservation of life having already been made, it is too late for us to cease to be ambitious.

Other objections to prolonging old age have to do with population control and age distribution. For example, it is asked, Dare we propose to add to a burden that is almost insupportable now? Shall the resources of underprivileged nations be consumed at an even faster rate by the technologically more advanced peoples of the Northern Hemisphere and of the West generally–those who will be the first to take advantage of new medical procedures?

In partial extenuation, it can be said that the increase in population would not be exponential, because it is unlikely that older people would choose to add to their families. Admittedly, though, they would have mouths, and they would use energy and other raw materials at the high rate characteristic of people in the developed parts of the world.

One hears that the likely increase in population size would provoke wars, as if the linkage were an established truth. But it does not stand up to scrutiny. No one will challenge Europe’s claim to the dunce’s cap for political aggression and warmaking, yet war has been no more frequent in Europe over the past hundred years than it was in medieval times or in the fifteenth century or in the seventeenth, even though the population has grown steadily.

The threat of gerontocracy–government by the aged and probably for the aged–is less easy to dismiss. Certainly old people require special attention, and their rising numbers would lay an extra burden on social-welfare services in a caring society. That burden would have to be shouldered mainly by the young. A vigorous elderly generation would also probably hold on to jobs that otherwise would pass to the young, thereby exacerbating unemployment. Who knows? A gerontocracy might have the nerve to impose a special tax on jobholders below some minimum age, and at the same time reward older jobholders with generous concessions.

Without minimizing these last worries, I must point out that the political and sociological effects of a population shift would not be felt overnight. We should have between fifty and 200 years to adapt.

The process might completely overturn our present ideas about work and retirement, but in reality such a revolution has been in progress for the past 150 years, as the proportion of older people in the population has grown with advances in medicine and sanitary engineering. It is reasonable to assume we can solve the problems of the future, since they are not qualitatively new.

JANE AUSTEN WROTE her novels around the turn of the nineteenth century, and they are a mine of information about the manners and attitudes of her day. Consider, in particular, Austen’s first published novel, Sense and Sensibility. The hero, Colonel Brandon, is rated at thirty-five an old man and quite past it–so much so that Marianne Dashwood, the eighteen-year-old girl whose hand he seeks, regards his suit as a kind of geriatric charade. In the book the question arises of laying down a sum to purchase a fifteen-year annuity for Marianne’s mother, who is described as a healthy woman of forty. The man who would have to provide for the annuity protests, “Her life cannot be worth half that purchase.” So Austen seems able to take for granted her readers’ doubt that a woman of forty could live to be as old as fifty-five.

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Suppose someone had told Austen’s contemporaries that their life expectancy could be doubled. If they were to react as some people do today, they would have held up their hands in horror at the impiety of interfering with nature–at the very idea that a man of thirty-five would not have one foot in the grave and that a woman of forty would live another fifteen years! Yet the average life-span of a century or more ago seems pathetically short from the perspective of today. How can we be certain that a generation as close to us as we are to Jane Austen would not look upon our fears with pained condescension?

Some lines by the poet Walter Savage Landor, which have the cadences of a requiem, seem to rebuke the wish to delay death:

Nature I loved; and next to Nature, Art.

I warmed both hands before the fire of life;

It sinks, and I am ready to depart.

Perhaps this declaration is a Christian acquiescence to an inevitable fate, but to me it sounds spiritless. A person who is loved and in good health has reason enough to want to live a few years longer than might seem to be his due: to learn, for example, how the grandchildren turn out, and whether the flux of history corroborates or refutes his expectations. A writer will want to complete his book, or even turn his thoughts to another, and no gardener will willingly surrender his hope of taking part in the wonder and joyous expectations of another spring. From the point of view of biology, the strength of our hold upon life has been the most important single factor in bringing us to our present ages and, indeed, in the fact that human beings have evolved at all.

Some of the evils that confront mankind–the havoc of war, for example–can be anticipated and guarded against. Others are more insidious. They are the outcomes of well-intentioned actions and could not have been predicted. I have in mind the deaths from cancer of the pioneers of x-radiography, who could not possibly have known that x-rays are among the most potent cancer-causing agents.

Likewise, overpopulation is the consequence of a reduction of mortality, especially in childhood, through medicine and sanitary engineering, which has not been matched by a corresponding reduction in the birthrate.

All else being equal, I think that the risk of unforeseeable catastrophe will probably be sufficient to turn us away from the research to extend life. But what I hope will happen is this: perhaps a dozen enthusiasts for the prolonging of life will go ahead and try to prolong their own lives. If they become wise and oracular nonagenarians or centenarians, they will be counted among the benefactors and pathfinders of mankind. If senlie dementia is their fate, they will have warned us off, and that would be an equally useful service.

My personal sympathies are with the daredevils who want to try out these new procedures. This kind of adventurousness has always been in the character of science, as Sir Francis Bacon, the Lord Chancellor of England, the first and greatest philosopher of science, and a pious and reverent man, believed. In one of his essays, he wrote:

   The true aim of science is the discovery
   of all operations and all possibilities
   of operations from immortality
   (if it were possible) to the
   meanest mechanical practice.

I count Bacon, therefore, as a man on my side.

Sir Peter Medawar won the Nobel Prize for Medicine and Physiology in 1960. He is currently a member of the scientific staff of the Medical Research Council, in Harrow, England.

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