n J.R.R. Tolkien's The Lord of the Rings, the dark lord Sauron lives for many thousands of years before the good guys finally off him, and never seems to become withered or frail. Similarly, the elves—fey creatures who are wiser and more graceful than human beings—are also immortal, echoing thousands of years of human mythology which insist that the infirmity and indignity of aging need not afflict everyone. And you know, 21st century medicine appears to agree.
In our world, there are ethical and religious arguments against life-extension technology, but attempts to suppress it through regulation are probably doomed to fail. There will always be holdout countries eager to help people while making a buck, and the supply of patients afraid of death or disability is all but inexhaustible. Put money and fear and greed together and there will be progress, you bet. In fact, pro-death regulations are arguably an elitist weapon aimed at the poor and middle class, while the wealthy travel overseas to increasingly sophisticated rejuvenation clinics. Politicians won't get away with that one for long, so the coming century will be a time when lifespan becomes, at least to some extent, a matter of personal choice.
Before we get into the specifics, let me note that I'm not a doctor, nurse, pharmacist, nutritionist, insurance actuary or counselor. I can't give medical advice or tell you how to live your life. I'm just reporting the facts as I've found them, and I encourage you to seek professional guidance before making any major changes in diet or lifestyle. Always remember: "Lab Notes" is sold (well, given away free) as a novelty only. Any misuse of this information is your own problem. OK?
Also, while the ultimate goal of life extension (or any other medicine) is the prolongation of health and vigor, in practical terms it may simply extend the suffering and infirmity of old age, keeping us from dying even when we ought to. Alternatively, it could become a form of indenture: either forcing us to work long and hard for expensive treatments, or else forcing the young to pay the bills for mushrooming numbers of idle elderly. So it behooves all of us to think through the social implications, preferably before they hit us in the face. A stitch in time, as they say, saves 90 million down the road.
OK, so how is life extension accomplished? Not simply, alas. Aging is not one isolated phenomenon, but a whole swarm of inter-related ones. There are accident and injury, wear and tear—what we might tactfully refer to as "mileage." There are environmentally triggered illnesses, such as heart and lung disease, stroke, diabetes and cancer. Between them, these causes account for 70 percent of all deaths in the developed world, which simply underscores the importance of keeping fit, wearing your seat belt, eating a healthy diet and avoiding unnecessary dangers.
But there is also the slow steady oxidation of our tissues by free radicals—corrosive molecules produced by our high-energy metabolism. There is the decline in hormone production, leading to spiraling declines in the repair and maintenance functions of our bodies. There is the buildup of waste products in our cells, and the slow accumulation of genetic damage from background radiation and other sources. Even when they don't lead to cancer, these mutations interfere with the normal functioning of the enzymes and structural proteins we rely on. And finally there is the human genome itself, which switches from ally to enemy once our children (or perhaps our grandchildren) are born and raised. Yes, Virginia, we really are programmed to die.
Marriages of true minds admit immortality
What can we do about all this? A lot, actually, and still more in the years to come.
The first and simplest thing is antioxidant therapy. Antioxidants are chemicals which neutralize free radicals. Our bodies produce a few, such as a protein called superoxide dismutase, whose overproduction has been implicated in the ~100 percent lifespan increase of genetically modified nematode worms. Unfortunately, SOD is not available in pill form, but other antioxidants include the water-soluble vitamin C, the fat-soluble vitamin E and a molecule called alpha-lipoic acid, which is both water- and fat-soluble and appears to be particularly effective. Antioxidants don't just slow down the symptoms of aging by a few percent—they also reduce the incidence and severity of age-related conditions such as heart disease.
Another simple dietary life-extender is the regular consumption of, believe it or not, alcohol. In moderation (one to two drinks per day), beer and whiskey and especially wine appear to keep our arteries clear, warding off heart disease, stroke, arteriosclerosis and even various forms of mental illness and senility. As children, many of us were taught that alcohol harms your brain and body even in small quantities, but in fact the opposite appears to be true: Regular moderate drinkers are healthier overall, living an average of two years longer than nondrinkers. Just be sure not to drive, or sink into alcoholism!
Another common aging remedy is hormone replacement therapy. Our hormone levels decline with age, and the replenishment of chemical messengers like estrogen and testosterone can provide an increased sense of well-being and reduce the risk of heart disease and certain cancers. It's a delicate balance, though, because it can increase the risk of other diseases. Also, there's no clear evidence that these hormones—or growth hormone, another popular replacement target—actually increase lifespan. They may even decrease it slightly, or trigger unwanted body and personality changes.
Still, other hormones like melatonin (often packaged as a sleep aid) and DHEA (an ingredient in many bodybuilding formulas) are available over the counter, and do appear to increase the lifespans of lab mammals (5 percent for melatonin and up to 40 percent for DHEA) with few serious side effects. These may turn out to be "master hormones" that regulate the production of other compounds in the body. Still, no one really knows how these things work, or what doses are most appropriate for human health.
Another factor often overlooked in aging is autoimmunity and inflammation. As reported here in "The Autoimmunity Blues," more and more illnesses turn out to be our bodies confusedly turning against themselves, and in many cases the treatment is as simple as a baby aspirin or other anti-inflammatory drug. These can cause stomach irritation and ulcers and keep your blood from clotting properly—again, see your doctor!—but they are cheap and plentiful, and their role in a long and healthy life may be dramatic.
Another treatment—arguably both the most popular and the most effective—is marriage. As you may have heard, married people live an average of 10 years longer than single people do, which is bigger than the five-to-10-year difference between smokers and nonsmokers. More surprisingly, the children of married people live four years longer than children of divorced or single people. Divorce appears to be hard on everyone, physically as well as emotionally, while unhappy couples who stick it out have a stunning 88 percent chance of reconciliation within five years. Think about that.
Taking moderation to the extreme
What about reproduction? There doesn't seem to be any strong life-span effect, good or bad, in having children, though one imagines old age is easier with a few kids and grandkids around. Interestingly, though, research has shown that the germline cells which produce eggs and sperm also produce "death hormones" that shorten our lives. These are balanced by life-extending signals from the somatic cells in the surrounding tissue, but animal studies have shown dramatic longevity increases if the germline cells are removed. This strikes me as a high price to pay—the very sexuality that makes us human!—but I suppose some people might choose it over marriage if the option were presented. More importantly, we may find a way to mimic or enhance the somatic hormones.
To counteract various types of organ failure, there is always the option of surgical transplant. The perpetual shortage of donors has led to "xenotransplantation" research, where humans receive specially treated organs from genetically modified animals (usually pigs), but this research has a long way to go before it's cheap, practical or safe. Meanwhile, there is talk of "therapeutic cloning," where an organ (not a fetus!) is grown from an egg cell implanted with the patient's own DNA. This practice faces serious ethical and religious challenges, though, and may, for better or worse, be among the first longevity treatments to be banned outright in Western countries.
Similarly, the implantation of embryonic stem cells—"blank" cells that can grow into any tissue type as needed—has been shown to reduce the symptoms of just about every degenerative disease there is. Unfortunately, the cells are harvested from aborted human embryos, which many people find morally inexcusable, regardless of the benefits. So there are widespread attempts now to collect stem cells instead from discarded umbilical cords and circumcised foreskins, with mixed success.
This may not be necessary, though, if the secrets of a molecule called telomerase can be unlocked. As reported here in 1999 ("Does Dolly Have Old Age on the Lamb?"), every cell in our bodies has a counter—a "telomere"—at the end of each chromosome, which is shortened every time the cell divides. After about 30 divisions, the cell becomes "senescent" and will no longer multiply or perform certain other tasks. Senescence has been implicated in a number of age-related illnesses, and is thought to place a hard ceiling on human and animal life spans—the so-called "Hayflick limit"—around 120 years.
But an enzyme called telomerase, which is produced by germline cells, lengthens telomeres. It resets the counter, pushing back this limit. In fact, certain mutations (including cancers) activate the telomerase gene in ordinary tissue cells, rendering them immortal. If this trick can be performed on demand, we may be able to pull stem cells out of our own bone marrow, immortalize them, culture them in large numbers, and then inject them back into our bodies to repair worn-out tissues and organs. There's really no telling what effect this would have on life span, but I'm guessing it'd be huge, like 20 to 30 good years.
And then there is calorie restriction. For some reason, a nutritionally balanced near-starvation diet seems to increase the body's efficiency and dramatically decrease the production of free radicals and other waste products. Nobody likes to starve, but the good news is that there are researchers studying the chemical fingerprints of calorie restriction, with an eye toward mimicking them in a pill. Other medications under investigation may help clear the junk out of older cells.
Looking even farther ahead, there is the promise of nanotechnology. Some people opt to freeze their bodies after death, in hopes of revival in a bright nanotech future. To others, this smacks of desperation or hubris—a viewpoint with a solid pedigree of its own. Centenarian studies have shown that a positive, casual, uncomplicated attitude toward death and aging adds almost eight years of life all by itself, and is possibly the single greatest factor in living to 100 or beyond. So relax, amigos—you'll not only live longer, but extend the lives of the people around you.
The real key—and I can't stress this enough—is moderation in all things, including moderation itself. You could be hit by a truck tomorrow, right? Regular exercise and social interaction are at least as important as any pill or injection, and more rewarding besides. If we choose the right path in life, and keep it interesting, and keep our minds and bodies and taste buds engaged, then the experience is worthwhile no matter how long it lasts. It is, after all, the quality of life, not the quantity, that truly matters.
Wil McCarthy is a rocket guidance engineer, robot designer, science-fiction author and occasional aquanaut. He has contributed to three interplanetary spacecraft, five communication and weather satellites, a line of landmine-clearing robots and some other "really cool stuff" he can't tell us about. His short fiction has graced the pages of Analog, Asimov's, Wired and other major publications, and his novel-length works include the New York Times notable Bloom and The Collapsium.
